|
Table 1.1: Change history
|
||||
|
date/time |
summary of changes |
number problems |
not solved |
solved but not verified |
|
Friday Dec 27, 2024. 1PM |
Finished Solving problems from Elementary Differential Equations. By Thornton C. Fry. D Van Nostrand. NY. First Edition (1929). Finished solving problems from "A short course on differential equations. By Donald Francis Campbell. Maxmillan company. London. 1907" Solving problems from Introductory Course On Differential Equations by Daniel A Murray. Longmans Green and Co. NY. 1924
|
18,482 |
1050 |
NA |
|
Friday Dec 20, 2024. 10PM |
Solving problems from Elementary Differential Equations. By Thornton C. Fry. D Van Nostrand. NY. First Edition (1929)
|
18,227 |
1046 |
NA |
|
Thursday Dec 19, 2024. 11PM |
Added new solver for second order, which tries to reverse the role of the independent and dependent variables in case all other methods failed. This resulted in 7 ode’s being solved now which were not solved before. Added two tables to show reverse the role for first and second order. improved solving for explicit solution from implicit. Finished solving all problems from DIFFERENTIAL EQUATIONS WITH APPLICATIONS AND HISTORICAL NOTES by George F. Simmons. 3rd edition. 2017. CRC press, Boca Raton FL. Finished solving problems from Elementary Differential Equations. By R.L.E. Schwarzenberger. Chapman and Hall. London. First Edition (1969) FULL BUILD
|
18,206 |
1044 |
NA |
|
Monday Dec 16, 2024. 9PM |
Added new solver for first order, which tries to reverse the role of the independent and dependent variables in case all other methods failed. This resulted in 20 more odes solved now. Need to do the same for second and higher order. Solving problems from new book: DIFFERENTIAL EQUATIONS WITH APPLICATIONS AND HISTORICAL NOTES by George F. Simmons. 3rd edition. 2017. CRC press, Boca Raton FL.
|
17,884 |
1046 |
NA |
|
Wed Dec 11, 2024. 4AM |
Added time varying support for second order ode when solving using Laplace method. This resulted in 7 more problems now solved. Added new field in DB which is the book solution from the back of the textbook if it is available. This is now used to check my solution against first before using odetest. If validating against book solution works, then done, else use odetest to verify the solution. Most of the odes that do not correctly verify with odetest uses laplace method with dirac delta in the RHS.
|
17,731 |
1066 |
NA |
|
Tuesday Dec 10, 2024. 10PM |
Added 14 of my own problems solving Laplace with variable coefficients for first order ode in my own misc. odes book as there was none in the textbooks I am using to illustrate this method. Removed assumption of positive when taking the inverse laplace transform as this makes dirac(t) become zero and solution then will not validate. Do not convert to piecewise of solution to Laplace ode, if this results in invalid verification. This resulted in 2 problems now verifying ok. I need now to start adding time varying support for second order ode with Laplace method as it now only does constant coefficients.
|
17,731 |
1081 |
NA |
|
Sunday Dec 8, 2024. 11PM |
Added support to solving first order ode using Laplace transform for time varying ode. Only polynomial coefficients of the independent variable are supported. See my ode algorithms page for details. Still need to do the same for second order ode. Add check in the laplace transform solver for ode to verify the solution. This was missing for some reason. This resulted is few ode’s using Laplace not verified, but the solution looks correct. It is very hard to get verification on solution from Laplace method. Even Maple’s own solution using method Laplace, some of them do not validated using odetest even though solution looks correct. Added separate tables for Laplace for varying coefficients and constant coefficients to make it easier to lookup.
|
17,717 |
1083 |
NA |
|
Sunday Dec 1, 2024. 11PM |
For higher order ode’s, I still do not implement reduction of order. So all these are failed. Changed the code to solve without reduction of order in this case until I get to implement reduction of order for higher order ode’s. This resulted in few ode’s now counted as solved. There was not many. Only 6 ode’s. Rebuild.
|
17,717 |
1071 |
NA |
|
Sat Nov 30, 2024. 5PM |
Finally, added support to solving shifted Euler. These are second order ode of form \((x-a)^2 y'' + (x-a) y + y = f(x)\) which are first solved by change of variable \(X=x-a\) to convert to standard Euler. The shift \(a\) must be the same in both coefficients. See my ode algorithm page for examples. Completed solving all problems from book Differential equations for engineers by Wei-Chau XIE, Cambridge Press 2010. Completed more problems from Differential equations and their applications, 4th ed., M. Braun. FULL BUILD.
|
17,717 |
1077 |
NA |
|
Wed Nov 27, 2024. 1AM |
Finished solving Differential equations. An introduction to modern methods and applications. James Brannan, William E. Boyce. Third edition. Wiley 2015 The non-linear system of ode’s, I left out for now, since I do not know these well. May in the future will add them. Added new table for linear system of ode’s solved using Laplace method. Solved about 190 problems from book V.V. Stepanov, A course of differential equations (in Russian), GIFML. Moscow (1958) Fixed detection of Euler ode for higher order ode, by also normalizing the ode and checking again. Also, for second order ode’s, added check if particular solution using variation of parameters leads to very complicated and very large result, then keep the integral as inert (unevaluated). This resulted in number of odes now being verified OK when before they could not be validated. Also the answers are now more clear, even though the integrals are not resolved. Solved more problems from book Differential equations for engineers by Wei-Chau XIE, Cambridge Press 2010. Still have more to solve from this book. Added missing latex, which I had there but overlooked adding, to solving Euler ode for second order. Also improved handling of basis function for Euler solver. This did not affect result, but is more accurate.
|
17,556 |
1064 |
NA |
|
Tuesday Nov 19, 2024. 7PM |
Solved more problems from Differential equations. An introduction to modern methods and applications. James Brannan, William E. Boyce. Third edition. Wiley 2015 Fixed HTML link problem in lookup tables. Now link point to correct problems.
|
17,149 |
1078 |
NA |
|
Friday Nov 15, 2024. 5AM |
Added new solver for reduced riccati ode. Updated my ode algorithms page for description. This is much shorter way to solving the reduced riccati \(y'=a x^n + b y^2\) where \(a,b,n\) are constants. Solved more problems from Differential equations. An introduction to modern methods and applications. James Brannan, William E. Boyce. Third edition. Wiley 2015
|
16,815 |
1066 |
NA |
|
Tuesday Nov 12, 2024. 3AM |
Added phase line diagram to all problems of type first order autonomous ode \(y'=f(y)\). Made new ode type first_order_ode_autonomous and kept first_order_ode_quadrature for ode of form \(y'=f(x)\) only. i.e. split the quadrature to two types now. This is because \(y'=f(x)\) is not autonomous. Note that ode of type \(y'=f(x,y)\) are not quadrature, and fall into other types such as linear or separable and so forth. The phase line diagram detects stable (sink), unstable (source) and semi-stable (node) type of equilibrium points. Made it vertical line instead of horizontal line. I still need to make improvements to this diagram, will do that next build. Corrected entry for Kamke 110 ode where I was missing a term.
|
16,789 |
1066 |
NA |
|
Sat Nov 9, 2024. 2AM |
Solved more problems from Differential equations. An introduction to modern methods and applications. James Brannan, William E. Boyce. Third edition. Wiley 2015
|
16,789 |
1066 |
NA |
|
Thursday Nov 8, 2024. 1AM |
Corrected problem that made Maple trace output not show. Solved rest of problems from book Theory and solutions of Ordinary Differential equations, Donald Greenspan, 1960. Started solving problems from Differential equations. An introduction to modern methods and applications. James Brannan, William E. Boyce. Third edition. Wiley 2015
|
16,744 |
1066 |
NA |
|
Monday Nov 4, 2024. 1PM |
Added summary of solutions at end of each solver run. Added to each book, a lookup table as first section. Completed solving all problems in book Differential equations and linear algebra, Stephen W. Goode and Scott A Annin. Fourth edition, 2015. Completed all problems from book Differential equations, 3rd edition by Shepley Ross. Full build.
|
16,639 |
1062 |
NA |
|
Tuesday OCT 29, 2024. 11PM |
Finished solving all problems from Differential equations and their applications, 4th ed., M. Braun. Full build.
|
16,461 |
1045 |
NA |
|
Sunday OCT 26, 2024. 2PM |
Fixed problem in riccati solver. Removed few probems not meant to be in DB. Added handling for dAlembert when ode of form \(y=g(p)\) when \(g(p)\) is such it can not be solved for \(p\). i.e. form ode is not the normal \(y=x f(p)+ g(p)\). But for this to apply, \(g(p)\) must be not solvable for \(p\), otherwise other methods apply. Full build.
|
16,205 |
1042 |
NA |
|
Sunday OCT 20, 2024. 1PM |
Solved problems from book Elementary Differential Equations. By C. Henry Edwards, David E. Penney and David Calvis. 6th edition. 2008 number of small internal fixes. I still need to add these: add support for reduction of order for third order odes and add support for solving using Laplace method for variable coefficients odes. There are few problems like this in the above book which my solver could not now solve. Currently Laplace solver only can handle constant coefficient linear odes. Hopefully by next week will have these finished. Fixed few problems in database that I have typed incorrectly from the textbooks by hand. Full build.
|
16,207 |
1057 |
NA |
|
Sunday OCT 6, 2024. 11PM |
Spend last 4 months working full time to rewrite the whole internal workflow between solvers. This is to simplify the logic as it was just getting too complicated as it was. That is why I have not added more text book solutions. Now only solution which are verified are given. Hence no need to run verification phase afterwords as before, as verification is done by solver itself and solver will only return solutions that are verified. Hence the solved but not verified column in this table is no longer applicable. Fixed number of small bugs in the process. Now the number of unsolved odes is reduced. Kept the default to solve same ODE in as many different ways as detected. Improved Abel and Chini solvers. Much work still is needed to improve the Latex steps and show steps for solving for initial conditions as now I do not show these steps. Build now takes about a whole week to complete including compiling the Latex. Need to find me a faster PC as this is just too slow. Full build.
|
15,568 |
1032 |
NA |
|
Tuesday Sept 14, 2024. 10PM |
Full build to clean a bug in detecting Bessel ode which causes some solution to be solved as Bessel ode when it was not. |
15,568 |
1170 |
N/A |
|
Sunday June 30, 2024. 10PM |
Full build to set the colors on the plot as before I use command line and that does not support colors. Also fixed two ode which had typos. |
15,568 |
979 |
42 |
|
Monday June 23, 2024. 10PM |
Full build. |
15,568 |
980 |
45 |
|
Monday June 3, 2024. 11PM |
Improved integration using smart_int() and fixed checking for implicit solution in some places. This resulted on 6 more ode’s solved now and one more verified than last build.
|
15,569 |
981 |
40 |
|
Sat. June 1, 2024. 3AM |
Full build. Improved quadrature solver for first order to better handle IC.
|
15,569 |
987 |
41 |
|
Monday. May 20, 2024. 1PM |
Fixed bug in quadrature first order. There was case it was not veifying the solution satisfies the ode.
|
15,569 |
994 |
40 |
|
Thursday. May 16, 2024. 2PM |
Solved more problems.
|
15,569 |
990 |
40 |
|
Monday. May 13, 2024. 1PM |
Solved more problems.
|
15,564 |
990 |
40 |
|
Sat. May 11, 2024. 11PM |
Solved more problems.
|
15,532 |
987 |
40 |
|
Thursday. May 8, 2024. 3PM |
Added Maple step by step solution also for some problems. Fixed bug in verification of solution with IC. I had 8 solutions verified correct when they are actually not. Fixed bug where the check for dAlembert was giving true in some cases when it was not. Added check that for dAlembert and clairaut ode, the \(y'\) is not linear. I was missing this check even though it works without this check, but this leads to solving the ode using dAlembert or clairaut when other methods exists. Solved more problems. Full rebuild.
|
15,474 |
969 |
40 |
|
Wed. April 24, 2024. 6PM |
Solved more problems.
|
15,222 |
953 |
32 |
|
Tuesday. April 23, 2024. 7PM |
Solved more problems.
|
15,140 |
951 |
32 |
|
Tuesday. April 16, 2024. 9PM |
Solved more problems.
|
15,003 |
951 |
29 |
|
Friday. April 11, 2024. 11PM |
Solved more problems.
|
14,813 |
950 |
29 |
|
Monday April 8, 2024. 11PM |
Improved Latex. Solved more problems.
|
14,572 |
948 |
29 |
|
Thu. April 4, 2024. 3AM |
Rerun Maple again over all problems, added simplify(). Added latex showing steps to the new solvers :
|
14,408 |
948 |
31 |
|
Friday March 29, 2024. 4PM |
Solved more problems from INTRODUCTORY DIFFERENTIAL EQUATIONS. Martha L. Abell, James P. Braselton. Fourth edition 2014. ElScAe. 2014. Added two new solvers, but need to add steps (latex) yet.
See my ode algorithms report on main page for details. Full build. |
14,315 |
941 |
31 |
|
Sunday March 17, 2024. 3PM |
Solved more problems from INTRODUCTORY DIFFERENTIAL EQUATIONS. Martha L. Abell, James P. Braselton. Fourth edition 2014. ElScAe. 2014. Full build on Maple 2024 |
14,090 |
939 |
32 |
|
Sunday March 10, 2024. 3PM |
Solved more problems from INTRODUCTORY DIFFERENTIAL EQUATIONS. Martha L. Abell, James P. Braselton. Fourth edition 2014. ElScAe. 2014. Switched to Maple 2024. |
14,000 |
933 |
33 |
|
Thursday March 7, 2024. 11PM |
Full build. Fixed constants of integration so they are reset for each problem correctly. |
13,876 |
941 |
33 |
|
Sunday March 3, 2024. 10PM |
Solved more problems from INTRODUCTORY DIFFERENTIAL EQUATIONS. Martha L. Abell, James P. Braselton. Fourth edition 2014. ElScAe. 2014. |
13,876 |
940 |
34 |
|
Saturday March 2, 2024. 8PM |
Solving problems from new book INTRODUCTORY DIFFERENTIAL EQUATIONS. Martha L. Abell, James P. Braselton. Fourth edition 2014. ElScAe. 2014. Fixed few entries in database from last build. |
13745 |
940 |
32 |
|
Wed Feb 28, 2024. 9PM |
Solved all problems from Differential Equations by Alfred L. Nelson, Karl W. Folley, Max Coral. 3rd ed. DC heath. Boston. 1964 |
13724 |
942 |
38 |
|
Monday Feb 26, 2024. 11PM |
Solved more problems from Differential Equations by Alfred L. Nelson, Karl W. Folley, Max Coral. 3rd ed. DC heath. Boston. 1964 |
13416 |
939 |
36 |
|
Friday Feb 23, 2024. 10PM |
Finished solving all problems from Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020 |
13215 |
936 |
34 |
|
Tuesday Feb 20, 2024. 11PM |
Added support for solving higher order ode’s with missing \(y\). Also improved handling of constant of integrations by automatically generating them instead of hardcoding. |
13000 |
934 |
28 |
|
Monday Feb 19, 2024. 9PM |
Solved more problems from Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020 |
13000 |
960 |
28 |
|
Friday Feb 15, 2024. 8PM |
Solved more problems from Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020 |
12900 |
960 |
28 |
|
Thu Feb 15, 2024. 10PM |
Solved more problems from Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020 |
12611 |
954 |
28 |
|
Wed Feb 14, 2024. 9PM |
Finished solving all problems from Schaums Outline. Theory and problems of Differential Equations, 1st edition. Frank Ayres. McGraw Hill 1952. Solving problems from Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020 |
12495 |
954 |
28 |
|
Tue Feb 13, 2024. 9PM |
Full build. Fixed factoring of ode. |
12390 |
951 |
28 |
|
Tue Feb 6, 2024. 10PM |
Solved more problems from Schaums Outline. Theory and problems of Differential Equations, 1st edition. Frank Ayres. McGraw Hill 1952. |
12390 |
957 |
30 |
|
Sunday Jan 28, 2024. 11PM |
Full build. Solved problems from Schaums Outline. Theory and problems of Differential Equations, 1st edition. Frank Ayres. McGraw Hill 1952. |
12371 |
951 |
30 |
|
Sunday Jan 28, 2024. 11PM |
Full build, solved more problems. Imporved second order handling of transformation on \(y\) to make ODE constant coefficient (method 1) |
12166 |
952 |
31 |
|
Sunday Jan 7, 2024. 11PM |
Full build |
12081 |
927 |
30 |
|
Thu Jan 4, 2024. 2PM |
Fixed qudarture handling of tricky IC. Also improved homog. solver IC. Solving for IC is turning out to be the hardest of solvers actually. I need to rewrite all of this one day. |
12081 |
922 |
30 |
|
Monday Jan 1, 2024. 3PM |
Solved more problems. Full build for Mathematica to fix Latex |
12081 |
927 |
33 |
|
Thursday Dec 28, 2023. 9PM |
Rewrote laplace solver for first and second order to better handle mixed IC not all at same point or at zero. Full Build. |
11,946 |
872 |
32 |
|
Wed Dec 25, 2023. 10PM |
Solved more problems. Worked on IC handling for first order. Still need more work. |
11,946 |
875 |
31 |
|
Wed Dec 20, 2023. 1PM |
Full build. Started working on adding existence and uniqueness analysis for linear and non-linear second order ode. But not finished. |
11,897 |
842 |
30 |
|
Sunday Dec 17, 2023. 1PM |
Added existence and uniqueness analysis for linear and non-linear firt order ode. |
11,897 |
843 |
29 |
|
WED Dec 6, 2023. 2PM |
Finished solving problems from DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th edition. Brooks/Cole. Boston, USA. 2012 |
11,897 |
843 |
29 |
|
Sunday Dec 3, 2023. 3PM |
Solved more problems from DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th edition. Brooks/Cole. Boston, USA. 2012 |
11,878 |
843 |
29 |
|
Sunday Dec 3, 2023. 3PM |
If first order ode is quadrature, do not attempt to solve it using other types. I still do not handle IC well on some problems. need to fix those, this is why I had 4 problems now not verify. Full build. |
11,719 |
843 |
29 |
|
Friday Dec 1, 2023. 3PM |
Just bug fixes and table improvements. |
11,719 |
852 |
25 |
|
Wed Nov 26, 2023. 10PM |
Added new solver for second order to handle special case of \(A y''+B y'+Cy=0\) where it can reduce the order by one. Added support for special linear system and added 3 problems to test it. |
11,719 |
855 |
26 |
|
Sat Nov 25, 2023. 6PM |
Fixed bug in separable. There was one case where it could not separate it because I did not use normal(). |
11,716 |
858 |
26 |
|
Friday Nov 24, 2023. 2AM |
Fixed bug in Bessel ode solver. Worked more on linear system of equations. |
11,716 |
865 |
26 |
|
Sat Nov 18, 2023. 7PM |
Split solving system of linear ode’s summary table into two. One where matrix is defective and one when it is not. This makes it easier to locate problems with defective eigenvalues. Fixed table showing eigenvalues/eigenfunctions problems. |
11,716 |
890 |
26 |
|
wed Nov 15, 2023. 9PM |
Full build. Improved plots. Working on 3rd order ode, variation of parameters. |
11,716 |
893 |
26 |
|
Sat Nov 11, 2023. 10PM |
Added more plots for system of equations. (phase plots and solutions plots) and improved verification of solution to series. |
11,716 |
890 |
29 |
|
Thursday Nov 9, 2023. 7PM |
Added more problems from DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th edition. Brooks/Cole. Boston, USA. 2012 |
11,716 |
896 |
42 |
|
Tuesday Nov 7, 2023. 9PM |
New book added. DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th edition. Brooks/Cole. Boston, USA. 2012 |
11,552 |
896 |
42 |
|
Sunday Nov 5, 2023. 9PM |
More problems added. Full build. |
11,491 |
894 |
42 |
|
Sat Nov 4, 2023. 1PM |
More problems added. Full build. |
11,434 |
893 |
37 |
|
Sunday Oct 29, 2023. 9PM |
Full build. Modified separable solver to reject explicit result from integration if 6 times as large as the integrand. This caused speed up and reduced complixity of handling large expressions. It uses now implicit solution instead. I need to find out how many problems this affected. |
11,266 |
887 |
34 |
|
Thu Oct 19, 2023. 10PM |
Add book DIFFERENTIAL and INTEGRAL CALCULUS. VOL I. by N. PISKUNOV. MIR PUBLISHERS, Moscow 1969. Fixed some table display Added book Ordinary Differential Equations by Charles E. Roberts, Jr. CRC Press. 2010 and few problems from Nonlinear Ordinary Differential Equations by D.W.Jordna and P.Smith. 4th edition 1999. Oxford Univ. Press. N |
11,228 |
887 |
35 |
|
Wed Oct 16, 2023. 9PM |
Full rebuild. Added zoom to images. |
11,069 |
882 |
35 |
|
Wed Oct 12, 2023. 9PM |
Rebuild Lie symmetry problems. Improved final simplification. This resulted in one solution now verifying when before it did not. Also added more Latex. Improved exact solver for first order ode. This resulted in few ode’s now verifying. |
11,069 |
891 |
27 |
|
Sat Oct 7, 2023. 10PM |
Full build. Fixed some tables. |
11,069 |
891 |
33 |
|
Thursday Oct 5, 2023. 11PM |
Added new book Differential Equations, Linear, Nonlinear, Ordinary, Partial. A.C. King, J.Billingham, S.R.Otto. Cambridge Univ. Press 2003 |
11,069 |
894 |
30 |
|
Monday Oct 2, 2023. 9PM |
Added more problems from APPLIED DIFFERENTIAL EQUATIONS The Primary Course by Vladimir A. Dobrushkin. CRC Press 2015. |
11,027 |
893 |
30 |
|
Sunday Oct 1, 2023. 4PM |
Added more problems from APPLIED DIFFERENTIAL EQUATIONS The Primary Course by Vladimir A. Dobrushkin. CRC Press 2015. |
10,963 |
891 |
30 |
|
Thursday Sept 28, 2023. 10PM |
Improve finding Lie symmetry canonical ode for first order. Added more problems from APPLIED DIFFERENTIAL EQUATIONS The Primary Course by Vladimir A. Dobrushkin. CRC Press 2015. |
10,936 |
891 |
30 |
|
Sat Sept 23, 2023. 11PM |
Improved Latex for Lie symmetry. Added timelimit on few operations that would hang. Rebuild all first order ode’s. Improved table layout to make them more clear by removing column not needed. |
10,874 |
885 |
28 |
|
Wed Sept 19, 2023. 7PM |
Speed up Lie algorithm and some improvements in solving for \(\xi ,\eta \). Added latex showing more steps involved. Removed latex showing verification that \(\xi ,\eta \) keeps ode invariant, as this was long and not needed. I have the steps already given in my main Lie symmetry report at my main site. Added one more book APPLIED DIFFERENTIAL EQUATIONS The Primary Course by Vladimir A. Dobrushkin. CRC Press 2015. |
10,874 |
887 |
28 |
|
Sat Sept 16, 2023. 10PM |
Improved more the Lie symmetry algorithm, the part that finds \(S,R\). See updates flow chart on my Lie symmetry page. Rebuild |
10,796 |
924 |
28 |
|
Friday Sept 15, 2023. 11PM |
Full build. Improved Lie symmetry for first order. See updated algorithm in my study note for Lie on my main page. This resulted in 4 more Lie symmetry ode now to be solved. |
10,796 |
930 |
28 |
|
Tuesday Sept 12, 2023. 11PM |
Added new book AN INTRODUCTION TO ORDINARY DIFFERENTIAL EQUATIONS by JAMES C. ROBINSON. Cambridge University Press 2004 |
10,796 |
934 |
28 |
|
Monday Sept 11, 2023. 5PM |
Added more problems from AN INTRODUCTION TO ORDINARY DIFFERENTIAL EQUATIONS by JAMES C. ROBINSON. Cambridge University Press 2004 |
10,769 |
934 |
28 |
|
Sunday Sept 4, 2023. 7PM |
Added more problems from new book AN INTRODUCTION TO ORDINARY DIFFERENTIAL EQUATIONS by JAMES C. ROBINSON. Cambridge University Press 2004 |
10,711 |
934 |
27 |
|
Sunday Sept 3, 2023. 5PM |
Found a problem setting up the canonical ode for Lie symmetry. This is the tricky part where expressions in \(x,y\) need to be rewritten for that RHS of the \(S'(R)\) is in terms of \(R(x,y)\) only. So I fixed that. Hopefully no more problems. This resulted in solving few more problems now. Also fixed the table lookup for Lie’s for Bernulli ode. Had wrong sign! Added 50 problems from new book AN INTRODUCTION TO ORDINARY DIFFERENTIAL EQUATIONS by JAMES C. ROBINSON. Cambridge University Press 2004 |
10,669 |
935 |
27 |
|
Friday August 25, 2023. 9PM |
Fixed bug in first order homogeneousTypeMapleC solver. No wonder the table was empty. I did not check correctly for nops. Now the table showing these table are filled ok. Fixed and improved Lie symmetry solver for first order. Still more improvements are needed to speed it up.
|
10,619 |
946 |
26 |
|
Friday August 25, 2023. 9PM |
Fixed few more problems in Lie symmetry solver for first order. Added check for trivial \(\xi ,\eta \) found and in this case try again. It is still very slow as I try all possible permutations of polynomials in \(x,y\) up to degree 3. Need to improve this part. Finding \(\xi ,\eta \) is the main obstcle for this method. I also need to implement integrating factor method for Lie symmetry. I found there are short cuts to find there is the first order ode is know. So I am now making table of these, this will speed things alot. |
10,619 |
945 |
31 |
|
Friday August 11, 2023. 10PM |
Minor improvements to Lie symmetry solver for first order ode. |
10,619 |
936 |
33 |
|
Wed August 9, 2023. 2AM |
Have been working on Lie symmetry method. Currently I have it working for first order ode’s \(y'=f(x,y)\) using polynomial ansatz only. see my notes at https://12000.org/my_notes/symmetry_in_ode/report.htm. Full BUILD. |
10,619 |
946 |
33 |
|
Friday July 21, 2023. 1AM |
Added tables that show Lie symmetry found by Maple for those ode which has the symmetry. This will be useful when I add solving by Lie symmetry later on, which I am starting to workon. |
10,619 |
1034 |
28 |
|
Tuesday July 18, 2023. 9PM |
Added two new firts order solvers. One
called |
10,619 |
1034 |
28 |
|
Friday July 14, 2023. 7PM |
Fixed first order ode to handle better ode’s of form \(y^n=f(x,y)\). This resulted in one more ode solved. |
10,619 |
1056 |
28 |
|
Sunday July 9, 2023. 8PM |
Add new second order ode solver called bessel ode form A, which transforms \(a y''+b y'+ (c e^{r x} - m) y=0\) to Bessel and solves it. This resulted in few more ode’s solved. This uses transformation \(x=\ln t\),. |
10,619 |
1057 |
28 |
|
Wed June 28, 2023. 9PM |
Fixed exact solver to allow it to accept intergation factor that can’t be integrated. This result in few more problem now solved. |
10,619 |
1060 |
28 |
|
Friday June 23, 2023. 11PM |
Rewrote Clairaut and dAlembert ode solvers to improve the latex and flow and speed things up. Simplified things. FULL BUILD. (2 days). Fixed separable yet again to reject RootOf solution and keep implicit. |
10,619 |
1084 |
28 |
|
Thursday June 8, 2023. 7PM |
Full build again to fix plots. Abandon using cmaple.exe as it does not work. bad postscript driver. Also fixed some problems which did not record verify status correctly. |
10,590 |
1091 |
27 |
|
Wed May 31, 2023. 11PM |
Full build. improved latex, make build faster. |
10,590 |
1090 |
63 |
|
Wed May 31, 2023. 11PM |
Full build |
10,590 |
1090 |
43 |
|
Thursday May 25, 2023. 7PM |
Added option to solve same ode in all possible methods for second orde also. |
10,590 |
1089 |
54 |
|
Tuesday May 23, 2023. 6PM |
Added option to solve same ode in all possible methods. Now for first order ode only, next will add support for second order ode. This makes the book much larger but useful to see same ode solved in different ways. This reduces number of not verified as some methods do verify while other do not. |
10,590 |
1087 |
54 |
|
Friday May 19, 2023. 10AM |
Added problems from A First Course in Differential Equations by J. David Logan. Third Edition. Springer-Verlag, NY. 2015 and from Differential Equations by Shepley L. Ross. Third edition. John Willey. New Delhi. 2004 |
10,590 |
1086 |
84 |
|
Sat. May 13, 2023. 9PM |
Added solving by Taylor series method for first order and second order. I still need to add support for solving by power series for second order using Balance equation which will take 2-3 more days, then all work on series solver will be done. After that need to add support for solving higher order ode using Taylor series. Will not do power series for higher order ode’s. I need to go back working on adding support for finding integration function for nonlinear second order ode which I started looking at few months ago. That is much harder problem. |
10,330 |
1084 |
82 |
|
Sat. May 6, 2023. 10PM |
Started new rewrite of series solver to improve it. |
10,330 |
1084 |
82 |
|
Tuesday. Feb 21, 2023. 11PM |
Fixed one table to show type used for ode when it failed also. |
10,330 |
1086 |
82 |
|
Tuesday. Feb 21, 2023. 11PM |
Minor cleanup. |
10,330 |
1089 |
81 |
|
Friday. Feb 17, 2023. 9 AM |
More fixes to separable solver due to changes made in how it handles explicit vs. implicit choice. Added new table showing ODE’s solved by factoring. Now there are 34 such ode’s. Improved solution from Laplace to handle undefined in piecewise result. |
10,330 |
1087 |
85 |
|
Saturday. Feb 11, 2023. 9 AM |
Improved separable solver. Now selects the solution either explicit or implicit by veifying it first. This resulted in about 10 more problems being verified OK by Maple. |
10,334 |
1085 |
91 |
|
Friday. Feb 10, 2023. 11 PM |
Added few more problems from Cohen book. Added logic to factor the ode if possible when the original ode form produced no solutions. Needed to do this after trying the original form of the ode as is, else it can make some solvable ode’s not solvable any more (exact ode’s for example, Euler form for example). For an example, an exact ode if can be factored, the new factors no longer can be exact. Also improved separable to try isolate() as well as solve() to solve explicitly for \(y(x)\) before giving up and using implicit solution. This resulted in few more problems now being verified as isolate() can generate sometimes solution without RootOf compared to solve. |
10,334 |
1089 |
97 |
|
Wed. Jan 4, 2023. 4 PM |
Fixed some of Kamke problems, added book problem number also to make it easier to locate the problem in the book. Only for chapter 6. |
10,321 |
1098 |
95 |
|
Sunday. Jan 1, 2023. 2 PM |
FULL BUILD. add more problems from Cohen book. Added support for detecting and solving second order linear ode which is exact by reducing it to first order. |
10,320 |
1097 |
95 |
|
Wed. Dec 14, 2022. 8 PM |
FULL BUILD. Fixed labels on the phase diagram for second order. some regression need to find. |
10,247 |
1087 |
96 |
|
Sunday Dec 11, 2022. 8 PM |
Add few more problems from Cohen book |
10,247 |
1083 |
93 |
|
wed Dec 7, 2022. 11 PM |
Add few more problems from Cohen book |
10,220 |
1084 |
93 |
|
Tuesday Dec 6, 2022. 9 PM |
Add few more problems from Cohen book, and new table for exact odes solved by inspection. |
10,204 |
1082 |
93 |
|
Monday Dec 5, 2022. 1 PM |
Add function to exact solver to try few integration factors by inspection. see Cohen book, page 23. This results in 40 more odes’s now being solved. |
10,184 |
1080 |
93 |
|
Sat Dec 3, 2022. 11 PM |
Did full build. added more problems from elementary treatise on differential equations by Abraham Cohen. improved exact solver for 1st order ode. |
10,184 |
1120 |
92 |
|
Tuesday Nov 29, 2022. 11 AM |
Did full build after making minor changes. |
10,151 |
1120 |
99 |
|
Sunday Nov 28, 2022. 10 AM |
Added more problems from An elementary treatise on differential equations by Abraham Cohen. Did full build. |
10,151 |
1119 |
96 |
|
Thursday Nov 24, 2022. 2 AM |
Added new book An elementary treatise on differential equations by Abraham Cohen. DC heath publishers. 1906. Added new table that shows ode’s solved using implicit solution. |
10,137 |
1119 |
96 |
|
Monday Nov 21, 2022. 2 PM |
Added routine to convert implicit to explicit at the very end when possible. |
10,106 |
1118 |
99 |
|
Sat. Nov 19, 2022. 1 PM |
Fixed few things in separable solver. |
10,106 |
1120 |
103 |
|
Saturday. Nov 5, 2022. 9 PM |
Been busy writing paper for arxiv on the kovacic algorithm showing my implemenation which I had in my solver for more than one year now. But it was all new implemenation, cleaning up few things in the process and removed all the latex from it as not needed. It turned out to be 1600 lines only in total. I used better way to find coefficients of Laurent series than I was using before. Cleaned minor problem in solving for initial conditions and did full rebuild. My goal is to be able to verify all the ode’s left not verified. But some of these do not verify because Maple’s odetest itself fails to verify my solutions, even though the solutions are correct and many match Maple’s own solution (those in series solution). There are still class of problems this solver can’t solve. These are the ones which current methods implemented can’t solve. For these I really need to learn and implement Lie symmetry group for solving ODE’s which I have small note here about. This will be the ultimate goal. But this would take long time to do (1-2 years may be) as it is hard subject to learn. This is what Maple uses to solve these hard ode’s this solver can’t solve. |
10,107 |
1120 |
107 |
|
Tuesday. Oct 14, 2022. 10 PM |
No new problems. Added new
type for second order ode called
|
10,106 |
1112 |
109 |
|
Monday. Oct 10, 2022. 3 PM |
No new problems. Cleaned all the string latex concatentation by making each line separate string to avoid maple warnings. This took few days. Added new table which show program solution next to Maple solution for each problem for easier comparison. Did full rebuild. |
10,106 |
1128 |
104 |
|
Friday. Sept 30, 2022. 11 PM |
No new problems. Added internal option to solve each ode in all possible ways found. But this will generate a very large book, over 200,000 pages or more. so I kept this option just for testing. This is a good way to find any hidden bugs by solving the same ode in all possible types found. Did full rebuild. |
10,106 |
1128 |
105 |
|
Tuesday. Sept 13, 2022. 10 PM |
4 new problems added. fixed minor bug. Full build |
10,106 |
1127 |
162 |
|
Monday. August 29, 2022. 10 PM |
No new problems added. Starting major redesign at top level, will take few more days. Updated design document/diagram. Made rebuild to make sure did not break anything so far. OK. |
10,102 |
1132 |
163 |
|
Thursday. August 18, 2022. 6 PM |
Added support for solving what Maple calls homogeneous, class C first order ode’s. This managed to reduce the number of unsolved odes by 9. Added more problems from Earl D. Rainville, Phillip E. Bedient. Macmilliam Publishing Co. NY. 8th edition. |
10,102 |
1135 |
171 |
|
Sat. August 13, 2022. 9 PM |
Added more problems from differential equations. By Earl D. Rainville, Phillip E. Bedient. Macmilliam Publishing Co. NY. 8th edition. 1997. Improved tables formatting for HTML using fixed width tables. |
10,068 |
1144 |
171 |
|
Tuesday August 9, 2022. 8 PM |
Added phase plot for all problem where possible. Added new book differential equations. By Earl D. Rainville, Phillip E. Bedient. Macmilliam Publishing Co. NY. 8th edition. 1997. Added new type for first order ode to solve \(y'=f(x) e^{a(x)+b y} + g(x)\) ode’s. Did full rebuild. |
10,000 |
1144 |
171 |
|
Sunday July 31, 2022. 11 PM |
bug fixes in new code added for type 22, 23. Added support for Laplace transform method when no initial conditions are given. |
9,933 |
1136 |
161 |
|
Friday July 28, 2022. 9 PM |
Added more problems from Elementary differential equations. By Earl D. Rainville, Phillip E. Bedient. Macmilliam Publishing Co. NY. 6th edition. 1981. Added new method to solve first order ode by detecting complete differentials. This simplifies many solutions that before would have taken much longer to solve. But it is not easy to detect complete differentials when solving this by hand. Also added better method to solve nonlinear second order ode’s with missing independent variable. Called it type 22. Add better method to solve missing dependent variable for second order. Called it type 23. |
9933 |
1175 |
159 |
|
Tuesday July 26, 2022. 10 PM |
Added more problems from Elementary differential equations. By Earl D. Rainville, Phillip E. Bedient. Macmilliam Publishing Co. NY. 6th edition. 1981. |
9867 |
1168 |
158 |
|
Monday July 25, 2022. 11 PM |
Added new book. Elementary differential equations. By Earl D. Rainville, Phillip E. Bedient. Macmilliam Publishing Co. NY. 6th edition. 1981. Fixed bug in Bessel ode solver where it was not correctly checking for the form of Bessel in some cases. Need to do Airy ode solver also. Will do that later. |
9850 |
1168 |
158 |
|
Saturday July 23, 2022. 8 PM |
Changes to how to verify the solution. Rebuild all Mathematica solutions to improve the latex. ALso added Bessel ODE solver to solve second order odes’. This also converts if possible a second order ode to Bessel ODE form. It uses Bowman 1958 transformation. This is based on this |
9836 |
1151 |
177 |
|
Friday July 14, 2022. 9 PM |
Added new first order ode type homogeneous type c to handle ode of form \(y'=f(a + b x + c y)^{\frac {1}{n}}\) which produces now better solution than when using d’Alembert since this avoids having to square or raise both sides of the ode to some power. This based on this . Added few more odes. |
9836 |
1226 |
199 |
|
Friday July 8, 2022. 10 AM |
Lots of code changes in ODE.mpl, the new object that now represents single ode of all types. Removed dsolver.mpl. Rebuild all Mathematica’s result also as new version 13.1 was out. FULL build. |
9831 |
1226 |
199 |
|
Friday July 1, 2022. 11 PM |
Wrote new module change_of_variable_manager just to handle second order ode transformation and dsolving using these when applicable. Four cases. See this for examples. FULL build. |
9831 |
1233 |
187 |
|
Monday June 20, 2022. 4 PM |
changed ode_type to be Object with constructor. Some bug fixes. Add more problems. |
9831 |
1231 |
219 |
|
Friday June 17, 2022. 1 PM |
Added more problems from Handbook of exact solutions for ordinary differential equations |
9766 |
1216 |
216 |
|
Wed June 8, 2022. 3 PM |
Added more problems from Handbook of exact solutions for ordinary differential equations |
9755 |
1213 |
216 |
|
Tuesday June 7, 2022. 10 AM |
Added more problems from Handbook of exact solutions for ordinary differential equations |
9740 |
1205 |
216 |
|
Thursday June 2, 2022. 2 PM |
Improve latex |
9703 |
1195 |
216 |
|
Sunday May 29, 2022. 3 PM |
No problems added. Improved the Latex display for Mathematica by listing each solution in the list on separate line. Full rebuild for Mathematica now takes 2 days to do. Found bug in Mathematica when using FullSimplify. Posted at stackexchange. |
9703 |
1198 |
217 |
|
Monday May 23, 2022. 6 PM |
Added more problems from book Handbook of exact solutions for ordinary differential equations, second edition by Polyanin and Zaitsev. |
9703 |
1198 |
217 |
|
Tuesday May 17, 2022. 10 AM |
Added more problems from book Handbook of exact solutions for ordinary differential equations, second edition by Polyanin and Zaitsev. |
9395 |
1126 |
195 |
|
wed May 11, 2022. 11 AM |
Added book Handbook of exact solutions for ordinary differential equations, second edition by Polyanin and Zaitsev. |
9292 |
1125 |
177 |
|
Saturday May 7, 2022. 10 AM |
More problems from DIFFERENTIAL EQUATIONS with Boundary-Value Problems. by ZILL etall. |
9181 |
1118 |
173 |
|
Thursday May 5, 2022. 4 PM |
Added 2 books A course in Ordinary Dierential Equations. by Stephen A. Wirkus, Randall J. Swift. CRC Press NY. 2015. 2nd Edition. and DIFFERENTIAL EQUATIONS with Boundary-Value Problems. DENNIS G. ZILL, WARREN S. WRIGHT, MICHAEL R. CULLEN. Brooks/Cole. Boston, MA. 2013. 8th edition. |
9157 |
1117 |
173 |
|
monday May 2, 2022. 1 PM |
Added more problems from Differential Equations: Theory, Technique, and Practice by George Simmons, Steven Krantz. McGraw-Hill NY. 2007. 1st Edition. Fixed a bug in linear system of equations solver. Was not correctly checking for non-linearity. Did not check for x(t)*y(t) case and it was trying to solve this as linear. So I fixed this now and rerun all problems again since my solver now can’t handle system of first order ode’s which is not linear. These are very hard to solve analytically and few are even possible. So will not support non-linear system of odes. These can be solved numerically. |
9044 |
1102 |
168 |
|
monday April 25, 2022. 1 PM |
Added more problems from Differential Equations: Theory, Technique, and Practice by George Simmons, Steven Krantz. McGraw-Hill NY. 2007. 1st Edition. Too many build problem due to large size of latex. |
8903 |
1086 |
165 |
|
monday April 18, 2022. 4 PM |
Full build. Removed solving second order ode using series method if all other methods fail, unless explicit hint to use series is given. This reduce the size of the solutions. Made new report from the database just for Mathematica and Maple to better compare their results. |
8836 |
1086 |
161 |
|
Wed April 13, 2022. 3 PM |
Added yet more problems from Differential Equations: Theory, Technique, and Practice by George Simmons, Steven Krantz. McGraw-Hill NY. 2007. 1st Edition |
8836 |
944 |
174 |
|
Tuesday April 12, 2022. 11 PM |
Have not been working on this for few days. Been busy with CAS integration tests. Added yet more problems from Differential Equations: Theory, Technique, and Practice by George Simmons, Steven Krantz. McGraw-Hill NY. 2007. 1st Edition |
8789 |
944 |
174 |
|
Tuesday April 6, 2022. 6 PM |
Added more problems from Differential Equations: Theory, Technique, and Practice by George Simmons, Steven Krantz. McGraw-Hill NY. 2007. 1st Edition |
8769 |
944 |
174 |
|
Tuesday April 5, 2022. 4 PM |
Added more problems from Differential Equations: Theory, Technique, and Practice by George Simmons, Steven Krantz. McGraw-Hill NY. 2007. 1st Edition |
8736 |
943 |
173 |
|
Wed March 30, 2022. 6 PM |
Added more problems from Differential Equations: Theory, Technique, and Practice by George Simmons, Steven Krantz. McGraw-Hill NY. 2007. 1st Edition |
8687 |
943 |
173 |
|
Thursday March 24, 2022. 7 PM |
Improved Latex for trace. Rebuild some ode’s. No functionality added. |
8648 |
942 |
173 |
|
Monday March 21, 2022. 10 PM |
Completed adding all Kamke book. Lots of Latex build problem due to large size of book. |
8648 |
947 |
172 |
|
Thursday March 10, 2022. 10 AM |
Add most of Kamke book ode’s. (1850). Only about 200 left. Added leafcount and CPU time for Maple’s and Mathematica solutions and did full build. lots of ode’s I can’t solve from this book as many I still do not have solvers for yet. |
8564 |
857 |
229 |
|
Thursday March 3, 2022. 6 PM |
Fixed bug in second order ode Laplace method. Added check in linear system of first order ode solver for non autonomous system. Currently I do not have solver for this. Need to add this in the future. I was not checking for this before. This was a problem from Coddington textbook chapter 6. Add more problems from Coddington. Fixed bug in solving for IC when solution was implicit. |
6694 |
185 |
124 |
|
Wed March 2, 2022. 7 PM |
Added more problems from Coddington textbook. Change first order solver so that if solving an ode using a hint does not yield a solution, is to try again with no hint. |
6680 |
184 |
123 |
|
Tuesday March. 1, 2022. 9 PM |
Improved verification of series solution. This made number of unverified solutions less than before. Added more problems from Coddington textbook. |
6652 |
184 |
123 |
|
Sunday Feb. 27, 2022. 7 AM |
Finished refactoring of the application. Added new large diagram of the design which is now more complete, done using VISIO. Added UNIT TEST main call to run all UNIT TESTS for each solver. Changed second order ode solver to try series solution if all other methods fail to find closed form solution. |
6621 |
184 |
297 |
|
Sat Feb. 26, 2022. 11 AM |
No added problems, but large refactoring of the application. to improve the overall layout and design. This is taking more time than expected. Still more to do. |
6617 |
218 |
290 |
|
Wed Feb. 23, 2022. 2 AM |
Added more odes from An introduction to Ordinary Differential equations. Earl A. Coddington. Dover. NY 1961. I do not support series solution for 3rd or higher order ode’s. Maybe add it in the future. |
6617 |
217 |
291 |
|
Tuesday Feb. 22, 2022. 3 AM |
Added book An introduction to Ordinary Differential equations. Earl A. Coddington. Dover. NY 1961. Fixed bug in higher order ode solver where I did not check for complex conjugate coming in pairs correctly. This only applies to higher order ode’s not second order. So remove this for now and just kept the solution as is in terms of complex expoenential. Need to fix this better in the future since using sin/cos is more clear than complex exponentials but need to figure a good way to do it for higher order ode’s. |
6595 |
215 |
291 |
|
Monday Feb. 21, 2022. 3 PM |
Added more problems from 11th edition of Elementary Differential Equations and Boundary Value Problems. Boyce and DiPrima. Higher order ode’s chapter added. I still do not support solving higher order ode’s with reduction of order. I need to add this functionality sometime. so 5 such problems could not be solved now. But all the rest were solved OK. |
6501 |
215 |
291 |
|
Sunday Feb. 20, 2022. 5 PM |
Added new book. 11th edition of Elementary Differential Equations and Boundary Value Problems. Boyce and DiPrima. I have the 10th edition in there already. Laplace chapter Added. Improved some latex for Kovacic algorithm and fixed couple of small bugs. |
6457 |
210 |
291 |
|
Sunday Feb. 20, 2022. 10 AM |
Added short description of Kovacic algorithm section. Added diagrams for each case. Added new section for problems from the three papers releated to this algorithm so easy to find. |
6444 |
210 |
291 |
|
Tuesday Feb. 15, 2022. 11 AM |
Imprved Latex, simplified. |
6434 |
210 |
292 |
|
Sunday Feb. 13, 2022. midnight |
Finished case 3 of original Kovacic algorithm. Now Latex shows all the steps. Added section 2 in the chapter for Kovacic which solves same ode using all cases \(n=1,2,4,6,12\) in order to compare the different algorithms on the same ode. Now there is only 9 problems in section 2. Still need to clean the Latex more and do more clean up of the Latex. Removed few duplicate ode entries I found. |
6434 |
210 |
292 |
|
Thursday Feb. 10, 2022. 3 PM |
Added steps for case 2 of Kovacic algorithm. Most of the main steps Latex is now there. This is based on original algorithm. Not the modified one. Split the kovacic package to 3 separates ones. One for each case. |
6441 |
210 |
291 |
|
Tuesday Feb. 8, 2022. 4 PM |
For second order ode’s, added new function to convert solutions where the basis functions are complex exponentials to convert the solution to use sin/cos with possible damping term to make the solution easier to read and match textbook more. This only applies to linear second order ode’s. It also improves how the final solution from kovacis algorithm looks using trig functions rather than complex exponentials. |
6441 |
210 |
291 |
|
Monday Feb. 7, 2022. 4 AM |
For case 1, for poles of order >=4 use partial fractions decomposition to find \(b\) instead of undetermined coefficients. For order \(<0\) changed to use long division method. Tested and this seems to work OK. Need to do more testing. |
6441 |
210 |
291 |
|
Sunday Feb. 6, 2022. 2 PM |
Fixed formating in Latex, and tables. Added more latex. Still working on case 1 of kovacic algorithm. main steps are now there but need to add little more details. Then will go to implement case 2 next week. This implemenation is based on original Kovacic paper and not Saunders/Smith modified algorithm. |
6441 |
210 |
291 |
|
Sat. Feb. 5, 2022. 4 PM |
Fixed labeles in tables. Added a check for ode \(z''=r z\) in Kovacic algorithm on \(r\) if do not depend on \(x\), then no need to run Kovacic algorithm as solution is obvious. So this way it shortened the solution. Only do the algorithm if \(r\) is rational function of \(x\). |
6441 |
210 |
291 |
|
Friday Feb. 4, 2022. 5 PM |
Full build. Added more information in tables for kovacic that shows pole orders and order at infinity in addition to case used and all cases found. This will help in testing also. |
6441 |
210 |
291 |
|
Wed Feb. 2, 2022. 3 PM |
Improved Latex, simplified some steps that were generating large output. Still in case 1 of kovacic algorithm. Made diagram. |
6441 |
211 |
292 |
|
Tuesday Feb. 1, 2022. 4 PM |
Finished adding all main steps to case one algorithm of kovacic solver. I need to add diagram also. But now all main steps are displayed. Will start on case 2 later this week. Case 2 is actually easier than case 1. My kovacis package now is now at about 2,600 lines of code due to Latex added. It will probably double in size before all three cases are finished. |
6441 |
211 |
292 |
|
Monday. Jan. 31, 2022. 3 PM |
Started to add Latex showing steps of Kovacis algorithm. Currently working on case one only. May be by end of the week will start on case 2. |
6441 |
211 |
292 |
|
Wed. Jan. 26, 2022. 3 PM |
Wrote new version of Kovacic algorithm based on original paper for case 1. Still need to do case 2 and 3. |
6441 |
211 |
292 |
|
Friday Jan. 21, 2022. 11 PM |
More testing of kovacic algorithm. Improved simplification of intermediate results. Not able to find ode which fail case 1 and case 2 but works with case 3, either \(n=4,6,12\). Problems from paper seem to have typo. They do not work as claimed. |
6441 |
211 |
292 |
|
Thu Jan. 20, 2022. 5 PM |
update kovacic table to indicate whichcase number was used to solve the ode. rebuild all. |
6440 |
213 |
292 |
|
Wed Jan. 19, 2022. 1 PM |
Changed step 3 in kovacic algorithm so that for \(n=1\) and \(n=2\) it now follows original paper by Kovacic and not Smith paper. Case 3 remains the same. I still need to add the step by step but waiting to make sure first the implementation is correct. |
6440 |
212 |
292 |
|
Tuesday Jan. 18, 2022. 8 PM |
Changed few ode for Kovacic which did not have rational coefficients. Need to improve my detection on this and reject such odes. Will do that next. |
6440 |
212 |
292 |
|
Monday Jan. 17, 2022. 10 PM |
rebuild all kovacis problems. Changed two problems in the kovacic collection odes not to use parameters. The problem is that in kovacic algorithm it needs to decide if \(d>0\) and having unknown parameter makes it not possible to decide without assumption. And example is Bessel ode. Where it gives Liovillian solution only for \(n\) being half odd integers. So for now, will only support kovacic ode’s that contain no unknown parameters. |
6440 |
212 |
292 |
|
Sunday Jan. 16, 2022. 10 PM |
Improved handling of poles for second order in kovacic algorithm. |
6434 |
214 |
292 |
|
Sat Jan. 15, 2022. 11 PM |
Just a rebuild. overlooked running over
some ode’s again last time after the fix.
do not know how this happened. Also, for
the second kovacis solution, if integration
results in special function, kept the
integral Inert. This also prevents problems
Maple has with verification of these
solutions, it also now agrees with Mapel’s
|
6434 |
234 |
292 |
|
Sat Jan. 15, 2022. 6 AM |
Fixed bug in step 3 of kovacic algorithm. There are still few ode’s that do not get solved using kovacic algorithm even though they should. I still need to find out why. It is possible I’ve made some mistake in the implementation from papers I am looking at. |
6434 |
240 |
315 |
|
Friday Jan. 14, 2022. 10 AM |
Added verification on \(\omega \) solution in step 3 of kovacic algorithm that is satisfies \(w'+w^2=r\). There are cases where solution \(w\) was obtained but it does not satisfy this riccati ode. Hence reject if this happens. This explains why I was getting some solved solutions that did not verify in the last build. Added about 840 problems in new chapter called kovacic collection of problem to solve these are ode’s solved using only the kovacic algorithm (using ’hint’="kovacic" option). This is for testing purposes. These problems are collected from the rest of the database which are all solved already using other methods (series, etc...) but can also be solvable using kovacic algorithm if requested. The use of ’hint’="kovacic" forces the solver to only try kovacic algorithm solver and no other. This will now make the full build to take more time. |
6434 |
266 |
315 |
|
Wed Jan. 12, 2022. 5 AM |
Fixed another bug in kovacic algorithm. Generating the s sequences was not correct. But need to find why some are not verified now. |
5598 |
206 |
298 |
|
Tuesday Jan. 11, 2022. 5 PM |
Fixed bug in kovacic algorithm. Also changed it to use solve(identity) to find the coefficients of the polynomial in step 3. This is much better. |
5598 |
215 |
292 |
|
Tuesday Jan. 11, 2022. 11 AM |
Full build. regression. 3 integrals fail now compared to last build. Need to find why |
5598 |
213 |
296 |
|
Sunday Jan. 9, 2022. 9 PM |
Minor bug fix. Refactor code in kovacic module. |
5598 |
210 |
296 |
|
Sunday Jan. 9, 2022. 6 AM |
Fixed bug in my kovacic alogrithm implementation. Need to add more tests. |
5598 |
211 |
296 |
|
Friday Jan. 7 2022. 6 AM |
Finally completed Kovacic algorithm but still need to add the latex showing the steps and need to test it more. 23 more ode’s now can be solved. But 4 seem to not have been validated. So need to find why. |
5598 |
223 |
296 |
|
Thursday Dec. 29 2021. 11 PM |
full build. Added more problems from Makarets and Reshenyak book. |
5598 |
246 |
292 |
|
Tuesday Dec. 28 2021. 5 AM |
full build. changes to dAlembert solver. Removed 2 problems not useful and were slow to verify by Maple. |
5584 |
246 |
292 |
|
sunday Dec. 26 2021. 9 PM |
Fixed linear fractional ode solver (called polynomial type), so it can handle missing \(x\) or \(y(x)\) in the numerator or denomator. Added more problems from Makarets and Reshenyak book. Need to handle what is called "Homogeneous ODEs of Class D" in Maple. Currently do not have solver for this. see problem 34, page 16 in Makarets and Reshenyak book as an example. book claims this is linear fractional ode, but do not see how this is the case so it was not detected. Improved polynomial type first order ode detection part. |
5586 |
250 |
291 |
|
sunday Dec. 26 2021. 2 AM |
Added more problem from Makarets and Reshenyak book. Fixed bug in first order initial condition which determines the constant of integration. Changed to limit instead of eval to avoid 1/0 problem. |
5574 |
249 |
290 |
|
sat Dec. 25 2021. 1 PM |
Fixed a bug in Liouville ode (type 18) solver. When it can’t integrate, do not call separable solver. This fixed two solutions. Adjusted type 17 solver to reject ode with rhs that depends on the independent variable. Can’t solve when this is the case. |
5547 |
248 |
290 |
|
Friday Dec. 24 2021. 12noon |
some bug fixed |
5547 |
248 |
292 |
|
Thursday Dec. 23 2021. 9AM |
added few more problems from Makarets and Reshenyak book. |
5547 |
249 |
297 |
|
Wed Dec. 22 2021. 10 PM |
added few more problems from Theory of differential equations in engineering and mechanics by K.T. Chau. to test Liouville transformation. Book has some typos in the problem section, so two new problems could not be solved using this transformation as expected. Did full build. |
5490 |
243 |
297 |
|
Tuesday Dec. 21 2021. 10 PM |
Completed Liouville ode solver. Added Liouville transformation. This is for ode of form \(y''+B(x) y' + C(x)y=0\) where transformation \(y(x) = u(x) e^{\frac {-1}{2}\int B(x) \,dx}\) makes a new ode \(u''+Q(x) u=0\) that could possibly be solvable now. Did full build. |
5483 |
240 |
298 |
|
Monday Dec. 20 2021. 10 PM |
Added solver for new second order type. Liouville ode of form \(y''+f(x) y'(x)+g(y) (y')^2=0\). But need to add more Latex still. Added few problems. Improved isobaric and homogeneous first order detection. Added more unit test to isobatic and homogeneous first order odes. |
5481 |
242 |
296 |
|
Thursday Dec. 16 2021. 3 PM |
Rewrote how homogeneous first order type is detected. Also improved the isobaric ode detection. Made the code into a Object and added unit tests. This made it easier to use. Rerun all the ode’s of these types. Also did full build for Mathematica version 13 results since it was released now. Maple is now at version 2021.2. Found a bug in Maple using solve. |
5475 |
242 |
294 |
|
Sunday dec 12, 2021. 11 AM |
improved more than handling of first order ode factoring. Added few more test problem. Did full build. This resulted in 2 more problems now solved. |
5475 |
243 |
294 |
|
Friday dec 10, 2021. 10 AM |
Fixed regression in last build rolled back the handling of first order ode. Now do only factor and look for \(y(x)\) in the left side if the result is of type *. Do not accept result if result is rational expression. This fixed 5 results which were not versified in last build. |
5472 |
245 |
294 |
|
Friday dec 10, 2021. 1 AM |
Full build. In first order, added 2 checks
to see if the ode can be broken into
product equal to zero. If so, solve each part
separatly. simplifies things. use |
5472 |
245 |
299 |
|
Wed dec 8, 2021. 3 PM |
Full build. Added check for first ode to handle solution \(y=0\). For example when input is \( y y' + y=0\), before it was just giving solution to \(y'+1=0\) and over looking \(y=0\). Fixed type 17 handling. Do not use particular and homogeneous solution on it. Does not work. Instead, just solve it as is when converting to first order ode. Now it gives same solutins as Maple. This took 2 days to find and fix and it is much easier method also. Maple keeps hanging on problem 2412 in the script. But when I stop the script, and start it again from 2412, it works. I have no idea why. |
5472 |
246 |
294 |
|
Sunday dec 5, 2021. 7 AM |
Added more problems. Working on adding Liouville ode pattern (not to be confused with eigenvalue boundary value problems with the name Sturm-Liouville which this program does not handle now). These are odes of the form \(y''+f(x) y'+F(y) (y')^2=0\). Currently the program does not detect these and can not solve them. I hope to add this new type soon. |
5472 |
249 |
292 |
|
Sat dec 4, 2021. 8 AM |
Add new transformation (called it type 17) for reduction of order by tranforming the dependent variable. This is for second order ode of the form \(f_1(y) (y'')^n + f_2(y) (y')^m = F(x)\). |
5453 |
240 |
292 |
|
Friday Dec 2 2021. 3 PM |
Added more problems from new book. THEORY OF DIFFERENTIAL EQUATIONS IN ENGINEERING AND MECHANICS. K.T. CHAU, CRC Press. Boca Raton, FL. 2018. Cleaned the statistic section. Imporved Mathematica’s build script. Fixed a bug in second order where kovciac method was being called twice. How did I not see this before? |
5436 |
240 |
292 |
|
Wed Dec 1 2021. 5 AM |
Improved how to check for type of expansion point using series method. Used Maple to check if the series expansion of coefficient is of type taylor instead of how I did it before, which was to check if limit exist. Added new Table which shows all problems not solved by this program and Maple. These are now counted as solved, as these problem can’t be solved using series method. |
5394 |
236 |
292 |
|
Tuesday Nov 30 2021. 7 PM |
Fixed series solver for first order and second order. When the RHS is not analytic at expansion point, do not solve as it needs asymptotic analysis which I did not implement yet. Before the program did not check the RHS correctly. Changed accounting so that if a problem was not solved but also not solved by Maple, it is now counted as solved as it means problem has no known solution. |
5394 |
245 |
285 |
|
Monday Nov 29 2021. 1 AM |
Added Mathematica solutions to compare against in addition to Maple. Added few problems for series solution when RHS is not analytic at the expansion point. I need to fix a bug I found in this yet. May be this week will be done. When the RHS is not analytic at expansion point, do not solve. |
5390 |
326 |
291 |
|
Tuesday Nov 23 2021. 11 PM |
Fixed yet another bug for supporting higher degree second order odes. Did not normal the ode in one place before the call. Still Need to add more test cases. Moved the build from worksheet to command line. It is much faster now. Takes only 5 hrs instead of 2 days. |
5386 |
326 |
288 |
|
Monday Nov 22 2021. 4 AM |
Fixed another bug for supporting higher degree second order odes. Was not handling symbolic exponents right. I think it is all now working OK. Need to add more test cases. |
5386 |
326 |
288 |
|
Sunday Nov 21 2021. 8 PM |
Fixes for supporting higher degree second order odes |
5386 |
328 |
288 |
|
Sat Nov 20 2021. 3 AM |
Added support to solve second order odes with degree not 1. Before only degree 1 could be solved |
5386 |
333 |
288 |
|
Sat Nov 20 2021. 11 AM |
Add more problems in my own section for enumeration of first order odes. Full build now takes 2 days to complete. |
5386 |
338 |
288 |
|
Thur nov 18 2021. 6 AM |
Add more problems in my own section for mainly testing by starting to enumerate all possible forms of odes. Will take much more time to complete. Cleaned the tables generated for better Latex formating. |
5333 |
329 |
287 |
|
Tuesday nov 16 2021. 1 AM |
Replaced signum that shows up in few placed by 1 by adding assumptions. Cleaned the verification code. Change solution that has heaviside to use piecewise. Changed lots of Latex to use breqn package |
5292 |
325 |
286 |
|
Sat nov 13 2021. 4 AM |
Add support for Lagrange adjoint equation method. Added few more problems |
5292 |
326 |
289 |
|
Thu nov 11 2021. 5 AM |
Added new book Ordinary differential equations and calculus of variations. Makarets and Reshetnyak and few probems from it |
5277 |
320 |
287 |
|
Thu nov 11 2021. 3 AM |
Added new transformation on independent variable to solve second order ode (type 15). see here for examples |
5265 |
315 |
225 |
|
Tue nov 8 2021. 9 PM |
added support for using integrating factor to solve second order ode of the form \(y^{\prime \prime }+p \left (x \right ) y^{\prime }+\left (p \left (x \right )^{2}+p^{\prime }\left (x \right )\right ) y = f \left (x \right )\) |
5265 |
318 |
223 |
|
Monday nov 8 2021. 2 AM |
Added more problems from (KREYSZIG, ADVANCED ENGINEERING MATHEMATICS) mostly Laplace |
5260 |
318 |
223 |
|
Sunday nov 7 2021. 7 PM |
Added more Laplace problems from KREYSZIG book. Added support for solving ode with shifted data using Laplace method. This is where initial conditions are not at \(t=0\). |
5240 |
318 |
223 |
|
Sunday nov 7 2021. 1 AM |
Added more problems from (KREYSZIG, ADVANCED ENGINEERING MATHEMATICS), series and Laplace. Added Table showing ODE’s solved using Laplace. Fixed a bug in linear systems Latex display |
5229 |
318 |
223 |
|
Friday Nov 5,2021 1 AM |
Added new book (KREYSZIG, ADVANCED ENGINEERING MATHEMATICS) and some problems from it (series). Also Added count of problems for tables also. Fixed small bug in first order series. |
5207 |
318 |
217 |
|
Thursday Nov 4,2021 10 PM |
simplify integrals with |
5167 |
318 |
210 |
|
Thursday Nov 4,2021 4 AM |
changed reduction of order solver to use formula \(y_2(x)=y_1(x) \int \frac {e^{-\int p \, dx}}{y_1^2} \,dx\) instead of how I did it before, which is by full derivation each time. This is much simpler. |
5167 |
318 |
210 |
|
Thu nov 4 2021. 3 AM |
cleaned riccati solver. |
5166 |
307 |
223 |
|
Monday nov 1 2021. 11 PM |
added more problems |
5166 |
307 |
223 |
|
Monday nov 1 2021. 1 AM |
added more problems |
5098 |
289 |
207 |
|
Sunday oct 31 2021. 9 AM |
added complex roots for indicial. This is the final act in series solution for second order. |
5082 |
286 |
203 |
|
Sat. oct 30 2021. 4 PM |
added more problems |
5082 |
300 |
189 |
|
Friday oct 29 2021. 1 AM |
Fixed another bug in coefficient to series conversion |
5039 |
298 |
183 |
|
Thu oct 29 2021. 1 AM |
added more problems, Fixed bug is coefficient to series conversion |
5039 |
300 |
182 |
|
Thu. oct 28 2021. 3 AM |
added more problems, change layout of document, fixed labels of ode’s |
5005 |
293 |
174 |
|
Tuesday oct 28 2021. 1 AM |
added more problems |
4921 |
285 |
149 |
|
Wed oct 27 2021. 11 PM |
Change all the latex to use breqn with tex4ht as well. |
4918 |
284 |
147 |
|
Tuesday oct 26 2021. 7 AM |
added more problems |
4917 |
283 |
148 |
|
Tuesday oct 26 2021. 6 AM |
added more problems |
4909 |
280 |
145 |
|
Tuesday oct 26 2021. 1 AM |
added more problems and fixed bug in generating series |
4883 |
280 |
142 |
|
Monday oct 25 2021. 5 PM |
added more problems |
4857 |
281 |
125 |
|
Monday oct 25 2021. 1 PM |
added more problems |
4812 |
281 |
88 |
|
Monday oct 25 2021. 9 AM |
Clean latex |
4774 |
281 |
82 |
|
Sunday oct 24 2021. 11 PM |
fixed bug. One off in series order |
4774 |
281 |
82 |
|
Sunday oct 24 2021. 7 AM |
fixed latex bugs |
4774 |
288 |
88 |
|
Sat oct 23 2021. 9 PM |
fixed bug in finding particular solution for series solver |
4774 |
287 |
89 |
|
Sat oct 23 2021. 10 AM |
Fixed few bugs in series solver |
4774 |
281 |
83 |
|
Friday oct 22 2021. 11 PM |
Finished all 3 cases for series. Complex root for indicial equation is left to do. |
4774 |
288 |
78 |
|
Friday oct 22 2021. 3 PM |
small fix. I was making the log term case of the above as solved by mistake. |
4774 |
298 |
71 |
|
Friday oct 22 2021. 8 AM |
fixed bug in series solver |
4774 |
283 |
71 |
|
Friday oct 22 2021. 4 AM |
add code for roots of indicial eq. differ by integer, case where log term is not needed. Series solver. |
4774 |
294 |
74 |
|
Tuesday oct 19 2021. 5 PM |
lots of Latex changes. Switched to breqn for PDF |
4760 |
314 |
70 |
|
Monday oct 18 2021. 5 AM |
working on series solver. |
4760 |
314 |
70 |
|
Sunday oct 17 2021. 11 PM |
working on series solver and adding problems |
4724 |
312 |
66 |
|
Friday oct 15 2021. 4 AM |
working on series solver and adding problems |
4724 |
312 |
68 |
|
Thu oct 14 2021. |
fixed latex/polynomial formating, series solver. |
4724 |
312 |
68 |
|
Thu oct 14 2021. 7 AM |
fixed bug. but now few do not verify more, due to polynomial issue. series solver. |
4724 |
312 |
64 |
|
Wed oct 13 2021. 7 PM |
regression. need to fix. Series solver |
4724 |
326 |
54 |
|
Monday oct 12 2021. 10 AM |
added repeated roots for frobenius series. Regression |
4722 |
309 |
82 |
|
Monday oct 11 2021. 4 AM |
fixed bugs in frobenius series for first order ode solver |
4716 |
325 |
48 |
|
Monday oct 11 2021. 1 AM |
added frobenius series for first order ode |
4716 |
325 |
50 |
|
Thu oct 7 2021. 5 AM |
added particular solution for frobenius series. regression |
4692 |
315 |
91 |
|
Wed oct 6 2021. 5 AM |
add more inhomogenous regular points. series solver. Still need to add the inhomogemous case. |
4673 |
309 |
49 |
|
Monday oct 4 2021. 9 PM |
Fixed bug in roots for indicial equation. |
4673 |
308 |
50 |
|
Monday oct 4 2021. 3 PM |
. added frobenius, but one case only. But have regression |
4673 |
308 |
81 |
|
Fri oct 1 2021. 6 PM |
No new code added. Added more problems only |
4673 |
320 |
48 |
|
Fri oct 1 2021. 5 AM |
. Fixed series bug, which affected new ode added. |
4649 |
320 |
48 |
|
Fri oct 1 2021. 1 AM. |
just code cleaning. Latex clean up. no new functionality |
4673 |
320 |
48 |
|
Tuesday sept 28 2021. 8 AM |
more fixed in series solver. REGRESSION happened. Need to fix later |
4673 |
320 |
68 |
|
Monday sept 27 2021. 4 PM |
regression. Changed MAX TERMS. |
4637 |
322 |
111 |
|
Thu sept 23 2021. 11PM |
Fixed below. still something is broke. I found why. I used to try series method on those ODEs that I can’t solve exactly. I removed this from the code. That is why the not solved increased. |
4495 |
276 |
47 |
|
Thu sept 23 2021. 7PM |
made FULL BUILD |
4495 |
258 |
40 |
|
Sunday sept 19 2021. 11 AM |
started on series solver |
4409 |
253 |
39 |
|
Monday sept 13 2021 2 pm |
Added series method for ordinary point, when all other methods for second order do not work |
4371 |
245 |
48 |
|
Sunday august 24 2021. 9 pm |
Added laplace method to solve linear odes |
4270 |
257 |
38 |
|
Thu march 11 2021. 10 PM |
Full build |
3944 |
257 |
14 |
|
Tue jan 19, 2021 4 PM |
odetest ON, improved simplification |
3769 |
215 |
9 |
|
Sunday jan 18, 2021 2 PM |
odetest ON, Fixed solve bugs, ALso changes all to simplify(size). need to rerun all |
3769 |
220 |
13 |
|
Sunday jan 17, 2021 10 AM |
odetest ON, Fixed some bugs in check solution |
3769 |
215 |
15 |
|
Sunday jan 17, 2021 6 AM |
odetest ON, added more options to check solution |
3769 |
215 |
20 |
|
Sat jan 16, 2021 10 AM |
(turned off odetest and moved product check ABOVE) |
3769 |
395 |
87 |
|
Wed jan 14, 2021 5 pm |
switched back to using ONE ode type to solve instead of all, was taking too long to build. |
3769 |
228 |
25 |
|
Mon jan 11, 2021 9 AM |
changed assuming to same line as odetest |
3769 |
219 |
19 |
|
Wed Dec 16, 2020 5 AM |
removed 2 problem which keep long time and Maple does not timeout |
3621 |
246 |
22 |
|
Monday Dec 14, 2020 7 PM |
after full rebuild for better latex |
3604 |
246 |
22 |
|
Sat Dec 6, 2020 NOON |
Major rewrite. Removed OOP and used just types instead |
3514 |
245 |
23 |
|
Wed Nov 25, 2020 6 AM |
added kovacic for inhomogeneous ode |
3478 |
247 |
22 |
|
Tuesday Nov 24, 2020 11 PM |
fixed riccati. removed abs. |
3469 |
247 |
22 |
|
Sat Nov 21, 2020 2 PM |
improved dAlemebert solver |
3466 |
247 |
25 |
|
Nov 11, 2020 5 AM |
added kovacic tranformation only which helped solve few odes that were not solved before |
3367 |
245 |
28 |
|
Oct 27, 2020 6 PM |
started adding eigenvalues/eigenvectors |
3267 |
266 |
31 |
|
Oct 27, 2020 7 AM |
changed constants of integration, lots of bugs fixed |
3266 |
266 |
30 |
|
Oct 18, 2020 5 AM |
spend all day fixing bug which caused this difference |
3126 |
266 |
32 |
|
August 7, 2020 10 PM |
add second order ODE with varying coeff, special case |
2517 |
204 |
29 |
|
August 5, 2020 1 PM |
changes to dAlembert solver |
2515 |
205 |
29 |
|
july 25, 2020 1 AM |
moved all input to use sqlite DB instead of plain text file |
2385 |
200 |
27 |
|
July 17, 2020 11 AM |
after fixing bug in exact solver |
2316 |
194 |
4 |
|
july 13, 2020 11 PM |
fixed detection of homogeneous ode |
2280 |
226 |
5 |
|
July 13, 2020 9 AM |
rewrote dAlembert solver |
2280 |
233 |
5 |
|
July 10, 2020 12:30 PM |
improvement in verify due to use _C1
instead of |
2266 |
235 |
5 |
|
July 6, 2020 1 PM |
Fixed |
2197 |
234 |
10 |
|
July 5, 2020 4 AM |
stil broke something in dAlembert. Need to fix |
2196 |
273 |
9 |
|
July 5, 2020 3 AM |
Broke something in dAlembert |
2196 |
276 |
9 |
|
July 2, 2020 11 AM |
this regression due to the homogeneous solver. Took out the simplify symbolic. put it back. |
2200 |
325 |
9 |
|
July 2, 2020 3 AM |
build |
2201 |
305 |
9 |
|
June 29, 2020 11 AM |
changes to handle |
2200 |
328 |
13 |
|
June 23, 2020 8 AM |
build |
2201 |
285 |
47 |
|
July 2018 |
started |
1 |
0 |
0 |