MATLAB: Matlab says the matrix is not symmetric

MATLABsymmetric

Hi!

I compute the following matrix: D = b'Ab, where A is a symmetric covariance matrix. D is high-dimensional and must be symmetric by definition.

But when I apply a functiion "issymmetric" to D, Matlab returns 0 meaning that it is not symmetric.

I guess the problem is the way Matlab handles calculations. But how to fix it and make sure that Matlab sees the symmetry of the matrix D?

Thank you in advance!

D = rand(100);
D = (D + D.')/2;
issymmetric(D)
ans =
  logical
   1

The sparse multiplication will skip multiplying the elements that are known to be 0 in the sparse matrix.

On a PC

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