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Path: utzoo!watmath!wateng!ksbszabo
From: ksbszabo@wateng.UUCP (Kevin Szabo)
Newsgroups: net.lang.c
Subject: Re: help converting multi-dim arrays
Message-ID: <2250@wateng.UUCP>
Date: Sat, 6-Apr-85 04:05:53 EST
Article-I.D.: wateng.2250
Posted: Sat Apr  6 04:05:53 1985
Date-Received: Sat, 6-Apr-85 05:57:30 EST
References: <569@utcs.UUCP>
Reply-To: ksbszabo@wateng.UUCP (Kevin Szabo)
Organization: VLSI Group, U of Waterloo
Lines: 25
Summary: 

In article <569@utcs.UUCP> you write:
>But, we still want to access the 
>matrices as:
>           ...data[row][col] ...
>Any ideas?
>Dave Harrison, Dept. of Physics, Univ. of Toronto: ..utzoo!utcs!physics

If you only have one matrix that you want to access, how
about:

static double *data;
#define	DATA(row,col)	(*(data + row*numcols + col))

Or if you only have a few, how about a couple of macro's?
You can even adopt the matrix format where the matrix is an array of
pointers.  It's all hidden in the macro.

The nice thing about this is that you could easily implement a sparse
matrix by redefining DATA to be a function or inline code.

#define	DATA(row,col) (*Find_address_of_sparse_array_element(row,col))

			Kevin
-- 
Kevin Szabo  watmath!wateng!ksbszabo (U of Waterloo VLSI Group, Waterloo Ont.)