Mathematica 9 is now available
Student Support Forum
-----
Student Support Forum: 'mathematica ndsolve - no output' topicStudent Support Forum > General > Archives > "mathematica ndsolve - no output"

< Previous Comment | Next Comment >Help | Reply To Comment | Reply To Topic
Author Comment/Response
Bill Simpson
02/24/13 7:13pm

In Response To 'Re: Re: mathematica ndsolve - no output'
---------
When I

"scrape-n-paste" your code into my notebook, a process that sometimes discard end-of-lines and thus can change the results,

and carefully put a semicolon between every pair of of expressions, which not doing has been a long standing source of very strange and hard to find and understand errors,

and turn my warning levels up high

then I get repeated warnings

Less::nord: Invalid comparison with -15.`+0.`I attempted.

that are from your

barrierV[x_] := Which[x<0, 0, x>a, 0, True, barrierHeight];

Those worry me. That makes me think it might always be returning the default value every time.

Changing that to

barrierV[x_] := (Print[x]; Which[x<0, 0, x>a, 0, True, barrierHeight]);

just prints a single x, not a value for x, and again repeats the multiple warnings. So I am guessing that it may be being called with a symbolic x rather than a numeric value.

If it were my code I would want to track down and make absolutely certain I had that critical function correct.

In spite of all that, the code finishes with

{0.13 Second, {{Ψ[x, t] -> InterpolatingFunction[{{-15., 15.}, {0., 200.}}, <>][x, t]}}}

and

Plot3D[Ψ[x, t] /. Out[24][[2, 1]], {x, -15, 15}, {t, 0, 200}]

displays a function==0 uniformly over the x,t range. Probably not what you were looking for.

If you have one machine it works on and another it doesn't then this is a wonderful opportunity for an experiment, assuming your prof will let you TOUCH his computer. Think what kinds of experiments you can do to test smaller parts of the code to try to sneak up on and catch the exact thing causing the problem.

URL: ,

Subject (listing for 'mathematica ndsolve - no output')
Author Date Posted
mathematica ndsolve - no output D. 02/20/13 9:31pm
Re: mathematica ndsolve - no output Forum Modera... 02/21/13 11:02am
Re: mathematica ndsolve - no output D 02/21/13 11:52am
Re: mathematica ndsolve - no output yehuda 02/21/13 7:02pm
Re: Re: mathematica ndsolve - no output D 02/23/13 9:58pm
Re: Re: Re: mathematica ndsolve - no output yehuda 02/24/13 6:31pm
Re: Re: Re: Re: mathematica ndsolve - no output Forum Modera... 02/24/13 7:33pm
Re: Re: Re: mathematica ndsolve - no output Bill Simpson 02/24/13 7:13pm
Re: Re: Re: Re: mathematica ndsolve - no output yehuda 02/25/13 01:48am
Re: Re: Re: Re: Re: mathematica ndsolve - no ou... D 02/27/13 9:54pm
Re: Re: Re: Re: Re: Re: mathematica ndsolve - n... jf 02/28/13 10:53am
Re: mathematica ndsolve - no output yehuda 02/28/13 5:07pm
< Previous Comment | Next Comment >Help | Reply To Comment | Reply To Topic