Matrix multiplication with logical values error

Question

Camilo A. 2016-10-31

编辑： Massimo Zanetti 2016-10-31

I have this matrix:

 M =
   3     0     0
   2     0     0
   0     3     4
   4     0     2

And I call these vectors:

 I=~(any(3==M'))', J=~any(3==M)
 I =
      0
      1
      0
      1
 J =
      1     0     0     1

Why I cant multiplicate "I*J"? And how can I fix it?

 I*J
 Error using  * 
 Both logical inputs must be scalar.
 To compute elementwise TIMES, use TIMES (.*) instead.

I want this result:

 ans =
   0     0     0
   0     0     1
   0     0     0
   0     0     1

Thanks

Answer 1

Massimo Zanetti 2016-10-31

编辑：Massimo Zanetti 2016-10-31

For logical matrices matrix multiplication doesn't apply (because it is not logical operation). To get your Dyadic product, cast to double:

dyd = double(I)*double(J)

NOTE: matrix product is not fully supported for integer classes in MATLAB, so casting to integer types (to save memory) won't work too..