Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!ucsd!ucsdhub!esosun!seismo!uunet!mcvax!dik
From: dik@cwi.nl (Dik T. Winter)
Newsgroups: comp.lang.fortran
Subject: Re: Should I convert FORTRAN code to C?
Message-ID: <7577@boring.cwi.nl>
Date: 5 Jul 88 00:34:00 GMT
References: <2742@utastro.UUCP> <20008@beta.UUCP> <224@raunvis.UUCP> <20531@beta.lanl.gov> <12302@mimsy.UUCP>
Organization: CWI, Amsterdam
Lines: 20

In article <12302@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes:
 > Again, this is convenient.  Unfortunately, it is also not standard, so
 > it cannot be used in general.  If one wants a flat array (because the
 > compiler is unable to vectorise the row-vector version, perhaps), one
 > must use the inconvenient access version, a[j*m + i] (with either the
 > flat allocation or the combined flat-plus-row-vector allocation).

Se essentially there are two ways to do the thing in C.  Now what if I
am writing a portable library, should I make two versions (one for
vector machines and the other for smart compilers)?  This is a bit
ridiculous, so we will get libraries (like IMSL, NAG and packages as
LINPACK etc.) in only one version.  And if the programmer started with
the other version, but found he needed a library routine, he is in trouble.
The big point is: you are not going to write a complete numerical system
from scratch, so you have no options; it is the library that dictates
the option (which is most likeley a flat array).
-- 
dik t. winter, cwi, amsterdam, nederland
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