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Re: problem inverting matrix [message #33430 is a reply to message #33429]

Mon, 06 January 2003 07:08

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Lars Schmidt (lars@itandesign.com) writes:

> I desperately hope someone of you has got an idea.
> I try to invert a matrix using "invert" of course with floating-point
> values.
> I get like explosion of values although the status variable I used with
> "invert" did not return any error and I also used the "/double" keyword.
> Has anybody an idea or experience with that. Are these numerical problems of
> the gaussian ellemination??

When these numbers "exploded", did anyone get hurt? There
is too much of this going on in the world right now. :-(

Did the numbers explode in the direction of 0?
That is, do these numbers look like some deranged
person's attempt to represent a very small number?
If so, it may just be your computer playing tricks on
you. Computers have a very difficult time representing
something as small as zero.

You might be interested in this article:

http://www.dfanning.com/math_tips/sky_is_falling.html

Cheers,

David

--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155

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[Message index]

		Re: problem inverting matrix By: Ralf Flicker on Mon, 06 January 2003 12:10
		Re: problem inverting matrix By: Lars Schmidt on Mon, 06 January 2003 10:18
		Re: problem inverting matrix By: Paul Van Delst[1] on Mon, 06 January 2003 09:20
		Re: problem inverting matrix By: Lars Schmidt on Mon, 06 January 2003 07:49
		Re: problem inverting matrix By: David Fanning on Mon, 06 January 2003 07:08

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