Carl Love

Carl Love

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13 years, 123 days
Himself
Wayland, Massachusetts, United States
My name was formerly Carl Devore.

MaplePrimes Activity


These are replies submitted by Carl Love

Trying to set a limit on the number of cores used by Maple by using the command kernelopts(numcpus= ...) only works if the limit is set immediately after a restart. The documentation implies (by omission) that the limit can be set at any time. See this MaplePrimes thread: http://www.mapleprimes.com/questions/215191-How-To-Limit-The-Number-Of-Processors

The safer alternative to subs is eval, which won't do substitutions that don't make sense mathematically:

eval(t, sol[3]);

@idol050279 The ImportMatrix command will convert a .csv file into a Maple Matrix. See ?ImportMatrix. You may need to use decimal points instead of commas (i.e., 0.05 instead of 0,05).

@Aaeru Michi You ask good questions that I don't know how to answer. Hopefully someone with more expertise in ODEs will join this thread. You may gain some insight by varying the method used by dsolve, for example method= rosenbrock, method= gear.

@Aaeru Michi I wouldn't exactly say that it "works" using mu(0) = 50, because here is the plot of R:

Rather, I'd say that it fails to give an error message.

You have a good point about the singularity (possibly) being removable. We need to figure out how to remove it. I don't have much expertise in this, but I suppose that it would help to have a guess for the value of limit(cot(x)*D(mu)(x), x= 0, right), which I think is the same as limit(D(mu)(x)/x, x= 0, right). Another way of looking at it is that we need the first nonzero term in the series expansion (which is not necessarily a power series) of D(mu)(x). Looking at the plot of D(mu)(x), I'd guess that that term is -x^p, with 0 < p < 1. That wouldn't be good enough to remove the singularity.

@Kitonum Thanks for spotting that. I've corrected the Answer.

@tomleslie The following example shows that vv's argument-switching workaround only works sometimes:

G1:= GraphTheory:-Digraph(4, {[1,3],[1,4],[2,1],[2,4],[3,1],[3,2],[4,2],[4,3]}):
G2:= GraphTheory:-Digraph(4, {[1,3],[1,4],[2,3],[2,4],[3,1],[3,2],[4,1],[4,2]}):

GraphTheory:-IsIsomorphic(G1,G2);
GraphTheory:-IsIsomorphic(G2,G1);

I'm sure that the procedure's author knows that isomorphism is a symmetric relation. It's just a bug.

@james1482 The following example shows that this bug is not about loops, nor about graph entry via adjacency matrix:

restart:
G1:= GraphTheory:-Digraph(4, {[1,3],[1,4],[2,1],[3,2],[4,1],[4,2]}):
G2:= GraphTheory:-Digraph(4, {[1,4],[2,3],[2,4],[3,1],[4,2],[4,3]}):
GraphTheory:-IsIsomorphic(G1,G2);

Error, (in GraphTheory:-DiIsomorphic) invalid subscript selector

However, as you say, the package is not designed to handle "graphs" with loops (which are not really graphs but rather multigraphs), so I don't see any point in the other respondents' attempts to test code on graphs with loops.

Do you mean a .mw file, a Maple worksheet? And by "source code" do you mean the startup code associated with the worksheet or the XML code that controls how the worksheet is displayed?

@hpc What do you want as the row indices of your table? For ChiSquare and StudentT, the row indices are degrees of freedom. There's not such a parameter for Normal.

@dc539 To be clear, Maple's read command doesn't care what the file extension is. All that matters is that the file being read is a plaintext file (i.e, no formatting other than line breaks) of Maple commands. You can create such a file from scratch with any text editor, or you can create it from a worksheet with File -> Export as -> Maple Input. Most people who write long Maple programs prefer to skip the worksheet and rather enter their code with a text editor.

@oscmh3 When you're editing a Question, there's a pull-down menu where you can select your Maple version. This information is very useful to the people who answer these Questions. I've already updated this Question's header, but please select your Maple version in the future.

@tayyab107 If you simply omit the discont option from the plot command, then the vertical line segment will appear.

@Preben Alsholm Thank you. Your information helped me to make a new diagnosis. See my next Answer.

The Elliptic and Jacobi functions are not handled by evalhf.

Does the existence in Maple of the function InverseJacobiSN help your situation (see ?InverseJacobiSN)?

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