Golub/Klema/Stewart

The Golub/Klema/Stewart matrix is upper-triangular with \(1/\sqrt{j+1}\) in the \(j\)’th entry of its main diagonal and \(-1/\sqrt{j+1}\) in the \(j\)’th column of the upper triangle. It was originally introduced as an example of where greedy Rank-Revealing QR factorizations fail.

C++ API

void GKS(Matrix<F> &A, Int n)
void GKS(AbstractDistMatrix<F> &A, Int n)

C API

ElError ElGKS_s(ElMatrix_s A, ElInt n)
ElError ElGKS_d(ElMatrix_d A, ElInt n)
ElError ElGKS_c(ElMatrix_c A, ElInt n)
ElError ElGKS_z(ElMatrix_z A, ElInt n)
ElError ElGKSDist_s(ElDistMatrix_s A, ElInt n)
ElError ElGKSDist_d(ElDistMatrix_d A, ElInt n)
ElError ElGKSDist_c(ElDistMatrix_c A, ElInt n)
ElError ElGKSDist_z(ElDistMatrix_z A, ElInt n)

Python API

GKS(A, n)