Re: deepening into fortran 90,95, 2003
- From: Gary Scott <garylscott@xxxxxxxxxxxxx>
- Date: Sat, 03 May 2008 01:39:28 GMT
glen herrmannsfeldt wrote:
Richard Maine wrote:
glen herrmannsfeldt <gah@xxxxxxxxxxxxxxxx> wrote:
[discussion of code optimization]
I disagree that it is useful at all for most people to look at generated
code. I haven't done so myself for ages. I particularly think it not
useful for relative novices such as the OP.
I agree for 'most' people. It is, though, fairly easy to
write Fortran that is much slower than it could be. Factors
of two easily, and even much larger factors.
I've been bitten many times by the slowness of concatenation of strings. In order to populate RTF fields, you sometimes need to build up an extremely long string from smaller chunks. Concatenation seemed the most obvious (naive) solution to me. But it was excrutiatingly, noticeably slow. Changing it to direct indexing was a huge speedup.
<snip> (see I snipped this time!!)
--
Gary Scott
mailto:garylscott@sbcglobal dot net
Fortran Library: http://www.fortranlib.com
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If you want to do the impossible, don't hire an expert because he knows it can't be done.
-- Henry Ford
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- deepening into fortran 90,95, 2003
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- Re: deepening into fortran 90,95, 2003
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- Re: deepening into fortran 90,95, 2003
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