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Topic: subtract vector from matrix rows without for loop
Replies: 7   Last Post: Sep 13, 2015 3:04 AM

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Matt J

Posts: 4,996
Registered: 11/28/09
Re: subtract vector from matrix rows without for loop
Posted: Nov 29, 2009 12:10 AM
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"Matt J " <mattjacREMOVE@THISieee.spam> wrote in message <hesupb$i07$1@fred.mathworks.com>...

> For loops may be optimal (looping along the smallest dimension of the matrix), when the smallest dimension is small enough.

In fact, for loops _are_ optimal, in terms of memory consumption, if you want to the new matrix to overwrite the old matrix. For example


will cause bsxfun() to generate an intermediate matrix the same size as M and then overwrite M with this intermediate matrix . Conversely, the following for-loop will allocate no new memory:

for ii=1:n

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