1.2 Change history

Table 1.1: Change history

date/time

summary of changes

number problems

not solved

solved but not verified

Tuesday OCT 29, 2024. 11PM

Finished solving all problems from Differential equations and their applications, 4th ed., M. Braun.

Full build.

16,461

1045
6.348%

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
6.436%

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
6.522%

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 Hence the solved but not verified column in this table is no longer applicable.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
6.628%

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
7.52%

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
6.28%

42
0.269%

Monday June 23, 2024. 10PM

Full build.

15,568

980
6.30%

45
0.289%

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
6.301%

40
0.257%

Sat. June 1, 2024. 3AM

Full build. Improved quadrature solver for first order to better handle IC.

15,569

987
6.339%

41
0.263%

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
6.361%

40
0.256%

Thursday. May 16, 2024. 2PM

Solved more problems.

15,569

990
6.360%

40
0.256%

Monday. May 13, 2024. 1PM

Solved more problems.

15,564

990
6.361%

40
0.257%

Sat. May 11, 2024. 11PM

Solved more problems.

15,532

987
6.354%

40
0.257%

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
6.262%

40
0.257%

Wed. April 24, 2024. 6PM

Solved more problems.

15,222

953
6.261%

32
0.210%

Tuesday. April 23, 2024. 7PM

Solved more problems.

15,140

951
6.28%

32
0.211%

Tuesday. April 16, 2024. 9PM

Solved more problems.

15,003

951
6.338%

29
0.193%

Friday. April 11, 2024. 11PM

Solved more problems.

14,813

950
6.413%

29
0.195%

Monday April 8, 2024. 11PM

Improved Latex. Solved more problems.

14,572

948
6.506%

29
0.199%

Thu. April 4, 2024. 3AM

Rerun Maple again over all problems, added simplify().

Added latex showing steps to the new solvers :

first_order_nonlinear_p_but_separable and first_order_nonlinear_p_but_linear_in_x_y

14,408

948
6.579%

31
0.215%

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.

first_order_nonlinear_p_but_separable and first_order_nonlinear_p_but_linear_in_x_y

See my ode algorithms report on main page for details.

Full build.

14,315

941
6.574%

31
0.216%

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
6.664%

32
0.227%

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
6.664%

33
0.236%

Thursday March 7, 2024. 11PM

Full build. Fixed constants of integration so they are reset for each problem correctly.

13,876

941
6.775%

33
0.244%

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
6.774%

34
0.245%

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
6.839%

32
0.233%

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
6.864%

38
0.277%

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
6.999%

36
0.268%

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
7.083%

34
0.257%

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
7.192%

28
0.215%

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
7.385%

28
0.215%

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
7.442%

28
0.217%

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
7.565%

28
0.222%

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
7.635%

28
0.224%

Tue Feb 13, 2024. 9PM

Full build. Fixed factoring of ode.

12390

951
7.675%

28
0.226%

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
7.724%

30
0.242%

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
7.687%

30
0.245%

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
7.825%

31
0.254%

Sunday Jan 7, 2024. 11PM

Full build

12081

927
7.673%

30
0.248%

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
7.673%

30
0.248%

Monday Jan 1, 2024. 3PM

Solved more problems. Full build for Mathematica to fix Latex

12081

927
7.673%

33
0.273%

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
7.299%

32
0.268%

Wed Dec 25, 2023. 10PM

Solved more problems. Worked on IC handling for first order. Still need more work.

11,946

875
7.325%

31
0.2595%

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
7.089%

30
0.252%

Sunday Dec 17, 2023. 1PM

Added existence and uniqueness analysis for linear and non-linear firt order ode.

11,897

843
7.089%

29
0.2437%

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
7.089%

29
0.237%

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
7.09%

29
0.244%

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
7.18%

29
0.247%

Friday Dec 1, 2023. 3PM

Just bug fixes and table improvements.

11,719

852
7.27%

25
0.213%

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
7.32%

26
0.222%

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
7.323%

26
0.222%

Friday Nov 24, 2023. 2AM

Fixed bug in Bessel ode solver. Worked more on linear system of equations.

11,716

865
7.383%

26
0.222%

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
7.596%

26
0.222%

wed Nov 15, 2023. 9PM

Full build. Improved plots. Working on 3rd order ode, variation of parameters.

11,716

893
7.622%

26
0.222%

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
7.596%

29
0.247%

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
7.647%

42
0.358%

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
7.756%

42
0.363%

Sunday Nov 5, 2023. 9PM

More problems added. Full build.

11,491

894
7.78%

42
0.365%

Sat Nov 4, 2023. 1PM

More problems added. Full build.

11,434

893
7.81%

37
0.323%

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
7.899%

34
0.301%

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
7.899%

35
0.311%

Wed Oct 16, 2023. 9PM

Full rebuild. Added zoom to images.

11,069

882
7.959%

35
0.316%

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
8.04%

27
0.243%

Sat Oct 7, 2023. 10PM

Full build. Fixed some tables.

11,069

891
8.04%

33
0.298%

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
8.07%

30
0.271%

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
8.09%

30
0.272%

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
8.127%

30
0.273%

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
8.14%

30
0.274%

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
8.138%

28
0.257%

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
8.157%

28
0.257%

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
8.55%

28
0.259%

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
8.61%

28
0.259%

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
8.65%

28
0.259%

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
8.67%

28
0.26%

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
8.72%

27
0.25%

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
8.76%

27
0.253%

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
8.91%

26
0.241%

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
8.9%

31
0.29%

Friday August 11, 2023. 10PM

Minor improvements to Lie symmetry solver for first order ode.

10,619

936
8.81%

33
0.311%

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
8.91%

33
0.311%

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
9.737%

28
0.264%

Tuesday July 18, 2023. 9PM

Added two new firts order solvers. One called homogeneousTypeD and the second homogeneousTypeD2. The first implements solver for ode that has form \(y'=\frac {y}{x} +g(x) f( \frac {y}{x} )\). This is what Maple calls homogeneous Type D. The second solver is more generic. It tries change of variables \(y(x)=u(x)x\) and if this results in ode in \(u(x)\) which is either quadrature or separable, then it is used. The above solvers resulted in more than 2 dozen ode’s now being solved ! I still need to make these solvers more robust, but the basic setup and latex is now all in.

10,619

1034
9.737%

28
0.264%

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
9.97%

28
0.264%

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
9.97%

28
0.264%

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
9.98%

28
0.264%

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
10.216%

28
0.264%

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
10.23%

27
0.2549%

Wed May 31, 2023. 11PM

Full build. improved latex, make build faster.

10,590

1090
10.23%

63
0.589%

Wed May 31, 2023. 11PM

Full build

10,590

1090
10.23%

43
0.406%

Thursday May 25, 2023. 7PM

Added option to solve same ode in all possible methods for second orde also.

10,590

1089
10.27%

54
0.5099%

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
10.26%

54
0.5099%

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
10.27%

84
0.787%

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
10.50%

82
0.794%

Sat. May 6, 2023. 10PM

Started new rewrite of series solver to improve it.

10,330

1084
10.50%

82
0.794%

Tuesday. Feb 21, 2023. 11PM

Fixed one table to show type used for ode when it failed also.

10,330

1086
10.51%

82
0.794%

Tuesday. Feb 21, 2023. 11PM

Minor cleanup.

10,330

1089
10.54%

81
0.784%

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
10.523%

85
0.823%

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
10.499%

91
0.881%

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
10.538%

97
0.939%

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
10.638%

95
0.9204%

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
10.6298%

95
0.9205%

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
10.608%

96
0.937%

Sunday Dec 11, 2022. 8 PM

Add few more problems from Cohen book

10,247

1083
10.569%

93
0.9076%

wed Dec 7, 2022. 11 PM

Add few more problems from Cohen book

10,220

1084
10.6067%

93
0.91%

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
10.6037%

93
0.9114%

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
10.6049%

93
0.9131%

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
10.9976%

92
0.9034%

Tuesday Nov 29, 2022. 11 AM

Did full build after making minor changes.

10,151

1120
11.0339%

99
0.9753%

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
11.0235%

96
0.9457%

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
11.0387%

96
0.947%

Monday Nov 21, 2022. 2 PM

Added routine to convert implicit to explicit at the very end when possible.

10,106

1118
11.06273%

99
0.9796%

Sat. Nov 19, 2022. 1 PM

Fixed few things in separable solver.

10,106

1120
11.0825%

103
1.0192%

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 second_order_ode_can_be_made_integrable which checks if an ode can becomes integrable as is when multiplied by \(y'\).

10,106

1112
11.0034%

109
1.0786%

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
11.1617%

104
1.0291%

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
11.16169%

105
1.03899%

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

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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

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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

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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

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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

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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

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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

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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

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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 DEtools:-kovacicsols. This now made the number of unverified solutions back to where it was before adding all the 840 ode. I still need to resolve the issue when few are not solved. All of these are in case 3, which takes very long time to complete.

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 factor and collect(ode,y(x)) and check if result is *. Need to go over the result more as I see 5 problems now do not verify. seems like regression.

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

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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

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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 exp/ln in reduction of order solver

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 C[1]

2266

235

5

July 6, 2020 1 PM

Fixed isobaric =>separable symblify(symbolic)

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 A*B case

2200

328

13

June 23, 2020 8 AM

build

2201

285

47

July 2018

started

1

0

0