MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi
Learn moreOpportunities for recent engineering grads.
Apply TodayMATLAB Central > MATLAB Newsreader > determinant calculation of integer matrices 

Subject: determinant calculation of integer matrices From: Matt J Date: 1 Apr, 2013 16:32:18 Message: 1 of 8 
P=magic(9)41 is a matrix of integers. You would therefore expect its determinant, whose calculation involves just products and sums of the P(i,j), to result in an integer as well. However, I get a noninteger result 
Subject: determinant calculation of integer matrices From: Bruno Luong Date: 1 Apr, 2013 16:48:10 Message: 2 of 8 
"Matt J" wrote in message <kjccqi$aje$1@newscl01ah.mathworks.com>... 
Subject: determinant calculation of integer matrices From: Matt J Date: 1 Apr, 2013 16:59:14 Message: 3 of 8 
"Bruno Luong" <b.luong@fogale.findmycountry> wrote in message <kjcdoa$dh8$1@newscl01ah.mathworks.com>... 
Subject: determinant calculation of integer matrices From: Bruno Luong Date: 1 Apr, 2013 17:22:06 Message: 4 of 8 
> Is there a reason that's supposed to be better than cofactor expansion? In the case of P=magic(9)41 one can see that a significant absolute error is obtained through LU, whereas with cofactor expansion, you would have none. 
Subject: determinant calculation of integer matrices From: Bruno Luong Date: 4 Apr, 2013 19:49:06 Message: 5 of 8 
Someone asks me off line why det (magic(9)  41) = 0. Here is how I see it: 
Subject: determinant calculation of integer matrices From: Bruno Luong Date: 4 Apr, 2013 19:51:06 Message: 6 of 8 
In the same way 
Subject: determinant calculation of integer matrices From: Bruno Luong Date: 4 Apr, 2013 20:16:19 Message: 7 of 8 
"Bruno Luong" <b.luong@fogale.findmycountry> wrote in message <kjklja$j3n$1@newscl01ah.mathworks.com>... 
Subject: determinant calculation of integer matrices From: Steven_Lord Date: 5 Apr, 2013 14:50:19 Message: 8 of 8 

No tags are associated with this thread.
A tag is like a keyword or category label associated with each thread. Tags make it easier for you to find threads of interest.
Anyone can tag a thread. Tags are public and visible to everyone.