sedumi：function handle problem in minpsdeig.m

[crucis0]

in minpsdeig.m （line 70）

sedumi/minpsdeig.m

Lines 66 to 74 in 2996306

	XX = reshape(XX,ki,ki);
	XX = XX + XX';
	if ki > 500
	if nnz(XX) < 0.1 * numel(XX), XX = sparse(XX); end
	[v,eigv(i),flag] = eigs(XX,1,'SA',struct('issym',true)); %#ok
	if flag, eigv(i) = min(eig(XX)); end
	else
	eigv(i) = min(eig(XX));
	end

there may be an issue in function eigs（XX，1，，‘SA'......）
matlab warn that XX is not a function handle.

[siko1056]

This change was done in 58d78d0, according to the Matlab documentation

• opts — Options structure

  Option Field	Description	Name-Value Pair
  issym	Symmetry of Afun matrix.	'IsFunctionSymmetric'

and

'IsFunctionSymmetric' — Symmetry of Afun matrix

and

Afun — Matrix function
function handle
Matrix function, specified as a function handle.

Matlabs warning seems justified here, as XX is a symmetric matrix .

The function is only used in this calling-order:

sedumi
  wregion
    maxstep
      minpsdeig

Maybe this is why this issue has not been hit often in the past. Can you provide a minimal example producing this warning message?

[siko1056]

The most simple fix is to just remove the struct from the call. Again according to the Matlab documentation:

If A is symmetric, then eigs uses a specialized algorithm for that case. If A is nearly symmetric, then consider using A = (A+A')/2 to make A symmetric before calling eigs. This ensures that eigs calculates real eigenvalues instead of complex ones.

Thus no special care for A is necessary to flag it symmetric. If there are no other opinions about it (or problems with older versions I am not aware of) I'll fix this in a few days.

[siko1056]

No further comments, merged #65 . Thanks again for your report 👍