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Re: call external speed [message #12776 is a reply to message #12686]

Thu, 03 September 1998 00:00

Karl Krieger
Messages: 8
Registered: April 1995

Junior Member

On Wed, 2 Sep 1998, curtis volin wrote:

> I use the IDL SVD command very frequently, so I was wondering if it would
> be any faster to create a DLL and call it with call external. I suppose
> that the fundamental question is, are IDL routines optimized for speed?

I guess it depends on the algorithm. A function designed for a specific
purpose will often be significantly faster if you code it with a compiling
language and link it to IDL by call_external. Just run a test case and
compare IDL's SVD to an implementation of SVD in C or Fortran.

BTW: I would recommend to use LINKIMAGE instead of CALL_EXTERNAL except
perhaps for some quick and dirty hacks. With LINKIMAGE your procedures and
functions have exactly the same syntax than the rest of IDL; you get
argument checking, proper IDL error handling and it is possible to pass
keyword parameters and structures to your routine. The downside is that it
requires some more programming effort but it's really worth it IMHO.

Karl
--
Max-Planck-Institute for Plasma Physics
Boltzmannstr.2, 85740 Garching, Germany Email: krieger@ipp.mpg.de

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[Message index]

		call external speed By: curtis volin on Wed, 02 September 1998 00:00
		Re: call external speed By: steinhh on Fri, 04 September 1998 00:00
		Re: call external speed By: rmlongfield on Fri, 04 September 1998 00:00
		Re: call external speed By: Karl Krieger on Thu, 03 September 1998 00:00
		Re: call external speed By: David Foster on Tue, 08 September 1998 00:00
		Re: call external speed By: Karl Krieger on Mon, 14 September 1998 00:00

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