[Octave-bug-tracker] [bug #59890] inf+1i*inf gives nan+1i*inf

[Rik]

Follow-up Comment #5, bug #59890 (project octave):

The core piece is this statement


1i*Inf


In Octave this results in NaN + Infi, while in Matlab it is 0 + Infi.  It
would seem that


(x + yi) * C = C*x + C*yi


except when x or y is zero in which case Matlab does not bother with the
multiplication.

Octave ordinarily just passes a multiplication like this down to BLAS.  Either
Matlab is checking for zeros and not performing multiplications on those
values as is done for sparse matrices.  Or maybe they have their own
customized version of BLAS to do this action, or maybe there is a flag to pass
to BLAS that determines how the non-finite values NaN, +Inf, -Inf are handled.




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