Simple array multiplication of incompatible sized arrays

Question

olivia 2023-9-5

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2017116-simple-array-multiplication-of-incompatible-sized-arrays

评论： olivia 2023-9-6

采纳的回答： dpb

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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

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Clay Swackhamer 2023-9-5

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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'

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Answer 1

dpb 2023-9-5

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https://ww2.mathworks.cn/matlabcentral/answers/2017116-simple-array-multiplication-of-incompatible-sized-arrays#answer_1302336

移动：dpb 2023-9-5

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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              