Comments on: Hooray For Arrays.Part(1) http://peoplesoftsqr.com/index.php/2009/07/hooray-for-arrayspart1/ When Peoplebooks Is Not Enough Mon, 16 Aug 2010 16:52:22 -0700 http://wordpress.org/?v=2.8.4 hourly 1 By: administrator http://peoplesoftsqr.com/index.php/2009/07/hooray-for-arrayspart1/comment-page-1/#comment-1441 administrator Mon, 27 Jul 2009 17:16:28 +0000 http://peoplesoftsqr.com/?p=414#comment-1441 I was comparing the external (user) view of spreadsheets to the external view of arrays. I don't <em>know</em> how every spreadsheet program manages its data, but I'd be surprised if a modern spreadsheet program didn't "allocate memory dynamically using a sparse matrix." For anyone working on a biography of me, you may note that I once wrote a spreadsheet program in interpreted BASIC that used a pre-allocated contiguous array. I extrapolated from very little evidence to comment on SQR arrays' memory model. Each field in an SQR array has a pre-allocated block of memory, but I cannot tell whether all those blocks are contiguous. Also, a string field has a contiguous block of string pointers, but I doubt the string space is allocated until used. That would make it potentially quite different from a COBOL array of strings of predetermined length. I was comparing the external (user) view of spreadsheets to the external view of arrays. I don’t know how every spreadsheet program manages its data, but I’d be surprised if a modern spreadsheet program didn’t “allocate memory dynamically using a sparse matrix.” For anyone working on a biography of me, you may note that I once wrote a spreadsheet program in interpreted BASIC that used a pre-allocated contiguous array.

I extrapolated from very little evidence to comment on SQR arrays’ memory model. Each field in an SQR array has a pre-allocated block of memory, but I cannot tell whether all those blocks are contiguous. Also, a string field has a contiguous block of string pointers, but I doubt the string space is allocated until used. That would make it potentially quite different from a COBOL array of strings of predetermined length.

]]> By: Bob Josephson http://peoplesoftsqr.com/index.php/2009/07/hooray-for-arrayspart1/comment-page-1/#comment-1437 Bob Josephson Mon, 27 Jul 2009 16:15:44 +0000 http://peoplesoftsqr.com/?p=414#comment-1437 Well, this is definitely not the topic I expected to see this week. Good article anyway. I assume another big difference between arrays and spreadsheets would be that spreadsheets allocate memory dynamically using a sparse matrix technique, whereas arrays are completely pre-allocated in a contiguous block. Well, this is definitely not the topic I expected to see this week.

Good article anyway. I assume another big difference between arrays and spreadsheets would be that spreadsheets allocate memory dynamically using a sparse matrix technique, whereas arrays are completely pre-allocated in a contiguous block.

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