Simple array multiplication of incompatible sized arrays

I would like to multiply these two arrays of different size and I am recieving the error :

"Arrays have incompatible sizes for this operation"

which makes sense, researching this question on other forums I found you can "Pad with zeros" and I would like to do that but I don't know how.

NEDsv=NED*SV;

%SV is a 62x3 double
%NED is a 186x3 double

[Clay Swackhamer]

I think matrix multiplication requires that the first matrix must have the same number of columns as the number of rows in the second matrix. So can you just transpose SV like this:

NEDsv = NED * SV'

Answer 1

[dpb]

What KIND of "multiply"? "*" is matrix multiplication and

SV=rand(62,3);
NED=rand(186,3);
M=NED*SV.';
whos M

  Name        Size            Bytes  Class     Attributes

  M         186x62            92256  double              

so you can multiply them if you transpose the second...of course, that may not be what you had in mind; you didn't tell us what you expected the result to be, but if one takes the hint about augmenting with zeros, then

M=NED.*[SV;zeros(size(NED,1)-size(SV,1),size(NED,2))];
whos M

  Name        Size            Bytes  Class     Attributes

  M         186x3              4464  double              

Of course, this is <element-wise multiplication>, something much different than <matrix multiplication> and uses the "dot" operator ",*".

[Bruno Luong]

"dot" operator ",*"

@dpb You are eligible for french citizenship, we prefer comma to dot. ;-)

[dpb]

@Bruno Luong -- chuckle...blame "fat fingers" instead....

[olivia]

@dpb thank you very much. I am also not sure what to expect for the result... :D but this worked