MatrixForm
- To: mathgroup at smc.vnet.net
- Subject: [mg62567] MatrixForm
- From: "David Park" <djmp at earthlink.net>
- Date: Mon, 28 Nov 2005 00:57:59 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Sometimes MatrixForm seems annoying because it is not transparent to other operations as some of the other Forms are. Actually, I think its design is very good because it allows one to write matrix equations with the Dot product in a nice form, and then easily evaluate them.
A = Array[a, {2, 2}];
B = Array[b, {2, 2}];
3 MatrixForm[A].MatrixForm[B]
% /. MatrixForm -> Identity // MatrixForm
The Dot product won't evaluate when the matrices are wrapped in MatrixForm and so we get the regular textbook form of a product. Notice also that the factor 3 was not sucked into the matrices. Using the rule MatrixForm -> Identity then evaluates the matrix multiplication.
I don't know how many users are aware of this usage. I have just begun to appreciate it and thought I would post a note on it.
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
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