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Re: Debugging Mathematica

  • To: mathgroup at smc.vnet.net
  • Subject: [mg94736] Re: Debugging Mathematica
  • From: m.r at inbox.ru
  • Date: Mon, 22 Dec 2008 05:16:28 -0500 (EST)
  • References: <gig3ms$2fg$1@smc.vnet.net>

Nikolaus Rath wrote:
> Hello,
>
> I have trouble debugging a function that I wrote. The function is of the =
> form
>
> f[x_,y_] := Module[{a,b}, ...]
>
> I am able to set a breakpoint in the function and Mathematica
> correctly stops execution.
>
> However, now I want to inspect the state of some local variables.
> Unfortunately some of them have very large contents (~500 000 reals),
> so when I open the stack and try to expand the "Local Variables" cell,
> the frontend just hangs.
>
> Is there a way to *selectively* display some of the local variables?
> What I would like most is to be able to execute code in the current
> stack frame, e.g. if I could simply evaluate a[[1]] in some notebook
> to get the first element of the local variable a. Is that possible?
>
> I am using Mathematica 7.
>
> Best,
>
>    -Nikolaus
>
> --
>  =C2=BBIt is not worth an intelligent man's time to be in the majority.
>   By definition, there are already enough people to do that.=C2=AB
>                                                          -J.H. Hardy
>
>   PGP fingerprint: 5B93 61F8 4EA2 E279 ABF6  02CF A9AD B7F8 AE4E 425C

Module renames the local variables, so you need to know their actual
names. Suppose you have Module[{a, b}, ...]; when a breakpoint is hit
type in a$ and then press Control-K (Complete Selection) to see the
symbols whose names start with a$ (or evaluate Names["a$*"]). Chances
are that the one with the largest number is the current one. If you
evaluate a$n, it will be stored in In[], so you may want to Clear or
Remove a$n later, otherwise it will not be freed because there is a
link to it.

Maxim Rytin
m.r at inbox.ru


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