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Article #795Actor: bad numerical precision?
From: Peter C. Bahrs
Date: Wed, 05 Dec 1990 05:22
Date: Wed, 05 Dec 1990 05:22
28 lines
1613 bytes
1613 bytes
Was: arghh!
I just wrote an inverse method for a matrix class using simple row
reduction.
a:=inverse(c);
b:=a*c;
Most of the time b is 1. 0. 0.
0. 1. 0.
0. 0. 1.
for a 3x3 matrix.
But sometimes, using different values for c, b is
1. 3.343434343-e20 1.2323-316
0. 1. 0.
0. 0. 1.
???What gives, I am confident the algorithm is correct. It works most
of the time. But this is a terrible error factor here that will build
up in time. Is Actor weak in numerical precison?
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!rex!rouge!cacs.usl.edu From: pcb@cacs.usl.edu (Peter C. Bahrs) Newsgroups: comp.windows.ms.programmer Subject: Actor: bad numerical precision? Message-ID: <20060@rouge.usl.edu> Date: 5 Dec 90 05:22:54 GMT Sender: anon@rouge.usl.edu Organization: The Center for Advanced Computer Studies, USL Lines: 28