MATLAB primme_svds/record_history error

[jeremy-myers]

An error occurs in MATLAB prime_svds() with the following minimum working example:

>> A = randn(1000,1000);
>> opts = struct();
>> opts.tol = 1e-10;
>> [U,S,V,R,STAT,HIST]=primme_svds(A,10,'L',opts);
Operands to the || and && operators must be convertible to logical scalar values.
Error in primme_svds/record_history (line 635)
      if stage == 0 && methodStage2 ~= 0
Error in primme_svds>@(a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13)record_history(a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13) (line 528)
               @(a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13)record_history(a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13));
Error in primme_svds (line 560)
      [ierr, svals, norms, svecsl, svecsr] = primme_mex(xprimme_svds, init{1}, ... 

It appears methodStage2 returns a vector and the if statement cannot parse this (MATLAB 2020a). A workaround is to change methodStage2 ~= 0 to any(methodStage2 ~= 0).

[eromero-vlc]

Thanks, Jeremy, for reporting the issue. I was able to replicated it on MATLAB 2021.

methodStage2 should be one number, which indicates the method used for the second stage. I'll dig in and figure out why primme_mex is returning a vector of numbers instead.

[eromero-vlc]

I pushed the fix on the master branch. Give it a try when you have a sec.