dense Q extraction and solve is sometimes erroneous for complex matrices
Submitted by Jeff Trull
Assigned to Nobody
Link to original bugzilla bug (#1493)
Version: 3.4 (development)
Description
Created attachment 809
Demonstrating that Q is applied incorrectly in some cases by using an identity RHS
HouseholderQR and ColPivHouseholderQR apply Q incorrectly on the right side, and Q' incorrectly on the left side, for the case of complex numbers. The latter case impacts solving as well, because Eigen needs to calculate Q'*RHS.
A simple test is to calculate the decomposition of a small matrix, and then apply it to the left and right of an identity matrix of the appropriate size. Both answers should be the same, but they are not. I've attached an example.
Attachment 809, "Demonstrating that Q is applied incorrectly in some cases by using an identity RHS":
repro2.cpp