I have a real sparse matrix, say A, of size 21660x21660. Here are my observations: 1. Running 0==max(max(abs(A-A'))) returns 1, so I could say that A is symmetric. 2. When I run issymmetric(A), it fails returning 0. 3. Trying issymmetric(A+A') also fails returning 0. 4. Trying issymmetric(full(A)) also fails returning 0. 5. The previous did not fail with a random symmetric sparse matrix of the same size. I'm shocked by number 3. Any thoughts? I'm using version 2016a.

Problems with issymmetric and sparse matrix

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Ivan Gonzalez Bustos le 20 Sep 2017

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Commenté : Ivan Gonzalez Bustos le 20 Sep 2017

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I have a real sparse matrix, say A, of size 21660x21660. Here are my observations:

Running 0==max(max(abs(A-A'))) returns 1, so I could say that A is symmetric.
When I run issymmetric(A), it fails returning 0. 
Trying issymmetric(A+A') also fails returning 0.
Trying issymmetric(full(A)) also fails returning 0.
The previous did not fail with a random symmetric sparse matrix of the same size.