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dpb
Posts:
8,982
Registered:
6/7/07


Re: matrix mean
Posted:
Sep 9, 2013 4:41 PM


On 9/9/2013 6:40 AM, Puneet wrote: > Hi  this is begginers question. > I have a data set  16 rows and 16 columns  I would like to average > every 2 points to get an 8 rows 8 columns matrix. > > This is a learning phase so I can run something similar later for larger > data sets. > Thanks.
One way...(not necessarily the best :) ) presuming that the "every 2 points" means in both directions given the resulting size of output for the described input. Similar works w/ filter() for the vector case.
m4=filter2(ones(2)/4,z); m4=m4(1:2:end,1:2:end);
Hint: look up 2D convolution... :)
accumarray() could be you friend amongst other ways to attack it...




