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5h
revised Why can't I import a file in the init.m file?
added 4 characters in body
5h
answered Why can't I import a file in the init.m file?
Oct
24
revised How to find out the current memory on the JVM?
added 4 characters in body
Oct
23
answered How to find out the current memory on the JVM?
Sep
30
awarded  Explainer
Sep
27
comment Mathematica integration failure - new or old?
@IgorRivin: there is WRI personal participating on this site, but I don't think they officially speak/act for WRI here and there most probably is not a well defined automatic process to create a bug report from errors reported to this site. So it does always make sense to report the bug to their support. It might even help to increase priority if it is sent more than once from different sources :-)
Sep
27
comment Smoothing a single rectangular pulse in NDSolve
how about the sum of two Tanh? I think the proper parametrization (how steep you make them) needs some information about your problem...
Sep
27
comment Save associations to a file and reload
thanks, that's very useful, wouldn't hav had "ExpressionList" on my mind. You might want to add that that problem hasn't anything to do with the fact that the OP is saving associations, he'd have had the very same problem with PutAppend lists or even just numbers...
Sep
27
comment A femme is a wife is a Frau
@eldo: you probably have noticed it by now, but the point is that you don't have to "find" that form for a given WA call but just click on the small + icon in the "pod cell" of your choice and select the "computable data" entry. That will insert a new input cell with exatly that arcane code. That's explained also in one of the ansers (currently that is the last one) to the questions kguler refered to...
Sep
17
comment Second order differential equation
... so you probably are best off to try what your professor suggested (another wellknown method to approach such problems). I would also think that it might be worth to rethink what problem that equation originated from and probably understand whether that singularity has a meaning in that context. Maybe you then can reformulate the problem in a way that is less problematic for numeric solvers...
Sep
17
comment Second order differential equation
@Marco: when you change eps you solve a different problem: if eps is > 0.75567 the solution to your problem will have w'[x]<0 for 0.75567 < x < 1 and there is no problem with the singularity. If eps gets about 0.75567, then the solution (at least the one Mathematica finds/tries with the shooting methods) will have w'[1]==0 and hits the singularity. It could be that there are other solutions which the shooting method as implemented in Mathematica just doesn't find (or you have to give it an initial guess). I don't think this will work here...
Sep
16
revised Second order differential equation
improved code and added output plot
Sep
16
comment Second order differential equation
@xzczd: I absolutely aggree that one shouldn't trust results of numeric algorithms in such situations (known potential singularities) blindly, and I have admittedly not made any tests about the quality of what NDSolve returns (and yes, only v10 will return a result at all). In this case I have also seen what you have seen, but I think that is because the current formulation is suboptimal in how it handles the eps parameter. I will update to show a more reliable way...
Sep
16
revised Second order differential equation
added note about this code only working in v0 and to be used with care
Sep
15
answered Second order differential equation
Sep
14
comment Why I can not get the plot when I use NDSolve`ProcessSolutions?
I have added some more variants to extract the solutions and some explanations. For these I'm making use of some slightly "advanced" features of Mathematicas pattern matching functionality, but as pattern matching is the very core of Mathematica it might be a good idea to learn at least some of it if you want to make good use of Mathematica...
Sep
14
revised Why I can not get the plot when I use NDSolve`ProcessSolutions?
addes some additional ways to extract solutions and some explanations of them
Sep
13
awarded  Excavator
Sep
13
answered Why I can not get the plot when I use NDSolve`ProcessSolutions?
Sep
13
revised How do I plot x[t] vs. x'[t] (where x[t] and x'[t] are solutions to NDSolve)?
just improved formatting a bit