ajfriedlan

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2 years, 228 days

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These are questions asked by ajfriedlan

 I'm confused as to why Maple can't perform a certain integral for me. Please see my attached code - it get's stuck on the last step.

 

070919_ThetaIntegral.mw

Hey there, I have a pretty general question.

I'm trying to fill out the entries of a matrix. Each matrix element is the result of a very complicated calculation. Currently, I am using nested do loops (two loops total) to scan through each row and column respectively. I find that this process racks up a ton of memory, and that I in fact run out of memory before the matrix has been completely specified.

First, why is this happening? And second, what is a smarter way to perform the calculation?

 

Cheers.

Hey there.

I've been using the threads package to parallelize some code. It's going well for the most part - my code runs way faster and I can observe with my System Monitor (ubuntu) that multiple cores are indeed being used. However, ~ 4 of every 5 times I try to run the exact same code, Maple will get stuck on a threaded calculation. If I follow the CPU usage in these instances, I see that one of the CPUs is maxed out at 100%. I am forced to quit Maple and kill the kernel process. Has anyone seen something like this before?

 

Thanks in advance.

Hello there,

I'm trying to write something like: dsolve=(myOde,numeric,method=rkf45,abserr=1e-7,relerr=1e( -(7+x) ) ),

where x is a variable that updates every loop of my for loop (say for example x = 2). I'm basically trying to improve my accuracy each iteration of the loop.

Anyways, Maple doesn't like how there is a variable in the expression for relerr - it returns the command just as I typed it, not, for example, as

dsolve=(myOde,numeric,method=rkf45,abserr=1e-7,relerr=1e( -(9) ) ).

How can I achieve my goal?

Thanks!

Hey there,

I've been struggling for a few days to integrate a function using rkf45.

For some context, I wish to numerically intergrate a function K * s_R (K,a,w) dK using runge kutta over a 2D grid of (a,w) values. Essentialy, performing the same sort of K-integral many different times for slightly different combinations of a and w. For one such (a,w) combination, the function looks something like this:

and rkf45 works just fine, and returns a numeric result. On the other hand, for a different combination of (a,w), the function looks like this:

and an attempt to perform rkf45 returns the following error: "cannot evaluate the solution past the initial point, problem may be complex, initially singular or improperly set up."

Here is a simplified version of my maple document for reference MaplePrimePleaseHelp.mw.

I'm happy to clarify anything that may be confusing and any thoughts or suggestions would be greatly appreciated.

Thank you!

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