7.46 January 28, 2014
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Top new questions this week:
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[Why are numeric division and subtraction not handled better in
Mathematica?]\url{http://mathematica.stackexchange.com/questions/40927/why-
are-numeric-division-and-subtraction-not-handled-better-in-mathematica}
There is something that has been troubling me for a while. At least in
version 7, the performance of a / b and a - b is not equivalent to, and
significantly inferior to, Divide[a, b] and Subtract[a, ...
- asked by Mr.Wizard (37 votes)
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[Cancellation of common
terms]\url{http://mathematica.stackexchange.com/questions/41070/cancellatio
n-of-common-terms}
Can someone explain why the term A in case 2 does not get canceled out
when case 1 does?
I use "9.0 for Microsoft Windows (64-bit) (January 25, 2013)"
case1 = A*(E^(-\[Lambda]) + \[Alpha]) == A;
Simplify[case1, A ...
- asked by user11946 (10 votes), answered by user11946 (2 votes)
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[Plotting time data with axes labels and point
labels]\url{http://mathematica.stackexchange.com/questions/41113/plotting-t
ime-data-with-axes-labels-and-point-labels}
I am trying to create a set of commands to automatically create clinical
lab value plots. Using time is my major issue here. It is hard to
dynamically reference the different point positions to ...
- asked by James Wine (10 votes), answered by ubpdqn (6 votes)
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[Is there a guideline about when to end expressions with
semicolons?]\url{http://mathematica.stackexchange.com/questions/41086/is-th
ere-a-guideline-about-when-to-end-expressions-with-semicolons}
Whether for nested Ifs or within scoping constructs like Module and
Block, I never know whether to end the final expression with a
semicolon. I know the semicolon suppresses output, but, for example,
...
- asked by acheong87 (10 votes), answered by Mr.Wizard (13 votes)
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[How to efficiently mask an
image?]\url{http://mathematica.stackexchange.com/questions/41125/how-to-eff
iciently-mask-an-image}
I want to extract/cut out a part of an image. Since my mask is not
rectangular I want to set pixels that are not masked to zero (black). My
current approach is something like this:
img = ...
- asked by chromate (9 votes), answered by Pickett (11 votes)
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[Why is this code slow and how could I speed it
up?]\url{http://mathematica.stackexchange.com/questions/41185/why-is-this-c
ode-slow-and-how-could-i-speed-it-up}
My goal is given an integer number to deduce if its digits increase (or
remain the same) from left to right or not.
Example: $1236, 123336$ are both considered numbers with increasing
digits, but ...
- asked by Zet (8 votes), answered by Kuba (13 votes)
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[How is the mysterious Raw function
used?]\url{http://mathematica.stackexchange.com/questions/40982/how-is-the-
mysterious-raw-function-used}
I have never seen an example use for the mysterious Raw function:
Raw[h, "hexstring"]
constructs a raw data object with head h, and
with contents corresponding to the binary bit pattern ...
- asked by Mr.Wizard (8 votes)
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Greatest hits from previous weeks:
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[How to play with Facebook data inside
Mathematica?]\url{http://mathematica.stackexchange.com/questions/11673/how-
to-play-with-facebook-data-inside-mathematica}
I saw this post from Wolfram here and I would like to know how to import
facebook data into Mathematica.
- asked by Murta (20 votes), answered by Murta (24 votes)
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[Is there an open source implementation of
Mathematica-the-language?]\url{http://mathematica.stackexchange.com/questio
ns/4454/is-there-an-open-source-implementation-of-mathematica-the-langua
ge}
I've seen questions before such as "What is the best open-source
equivalent for Mathematica?", but that specific question (and that line
of inquiry in general) cares more about the computer algebra ...
- asked by sblom (46 votes), answered by Simon (39 votes)
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Can you answer these?
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[Poor CUDALink performance, when calling a kernel multiple
times]\url{http://mathematica.stackexchange.com/questions/41102/poor-cudali
nk-performance-when-calling-a-kernel-multiple-times}
When working on a project of mine I noticed that CUDALink shows very
poor performance when calling CUDA kernels multiple times in a
loop-construct.
To demonstrate this I put together this little ...
- asked by definitely.uncertain (6 votes)
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[Does Mathematica compute free-form-input on Wolfram
servers?]\url{http://mathematica.stackexchange.com/questions/41238/does-mat
hematica-compute-free-form-input-on-wolfram-servers}
I've just started to use mathematica and I'm using the free-form input
alot. The computation time for simple problems seems to take alot of
time and my CPU isn't really used at all. I first thought ...
- asked by qwertz (4 votes)
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[Non linear model fit
mathematica]\url{http://mathematica.stackexchange.com/questions/41017/non-l
inear-model-fit-mathematica}
I want to fit experimental data (temp,alpha) to the following equation
for calculating k and Ea
-Log[alpha]^n = function(k,Ea,temp)
However i do not know exact value of "n". By this time i am ...
- asked by Farrukh Shehzad (1 vote)