Re: Matrix multiplication problem fixed via dot operation.
- To: mathgroup at smc.vnet.net
- Subject: [mg64600] Re: Matrix multiplication problem fixed via dot operation.
- From: Bill Rowe <readnewsciv at earthlink.net>
- Date: Thu, 23 Feb 2006 00:35:37 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
On 2/22/06 at 5:58 AM, c1572young at earthlink.net (Chris Young) wrote:
>To answer my own posting, it looks like the "dot" operator is
>needed when the matrices aren't both square.
>E.g.: a row vector with components a and b times a column vector
>with components c and d will yield the correct result, the
>dot-product.
>I'm still puzzled why Mathematica doesn't do the same thing without
>the dot.
Because it is very useful to do things like:
In[3]:={a,b} {c,d}
Out[3]={a c,b d}
And since for me (and I suspect most others) the need to multiply lists of things in the manner above arises much more frequently than the need for matrix multiplication, I am glad Mathematica reserves the implied multiplication syntax for this rather than matrix multiplication when matrices are involved.
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