MAGMA Forum

I am trying to perform the QR Decomposition of a square, complex matrix with pivoting. Can I use cqeqp3_gpu to get R and the pivoting vector, followed by cungqr_gpu to output Q? The cungqr_gpu description mentions that it uses the outputs of cgeqrf_gpu, but does not mention cgeqp3_gpu.

Yes, it appears that cungqr works with the output of cgeqp3. You can check by computing || A*P - Q*R || / (m * ||A||), where P is the permutation defined by jpvt. [See LAPACK working note 41 for error checks.]

-mark