GEQRT2 - 5.2 English - 68552

AOCL API Guide (68552)

Document ID
68552
Release Date
2025-12-29
Version
5.2 English
template<typename T>
void geqrt2(integer *m, integer *n, T *a, integer *lda, T *t, integer *ldt, integer *info)#

GEQRT2 computes a blocked QR factorization of a M-by-N matrix A

using the compact WY representation.

Purpose:

  GEQRT2 computes a QR factorization of a real M-by-N matrix A,
  using the compact WY representation of Q.
Parameters:
  • M[in]

    M is INTEGER

    The number of rows of the matrix A. M >= N.

  • N[in]

    N is INTEGER

    The number of columns of the matrix A. N >= 0.

  • A[inout]

    A is REAL array, dimension (LDA,N)

    On entry, the real M-by-N matrix A. On exit, the elements on and above the diagonal contain the N-by-N upper triangular matrix R; the elements below the diagonal are the columns of V. See below for further details.

  • LDA[in]

    LDA is INTEGER

    The leading dimension of the array A. LDA >= fla_max(1,M).

  • T[out]

    T is REAL array, dimension (LDT,N)

    The N-by-N upper triangular factor of the block reflector. The elements on and above the diagonal contain the block reflector T; the elements below the diagonal are not used. See below for further details.

  • LDT[in]

    LDT is INTEGER

    The leading dimension of the array T. LDT >= fla_max(1,N).

  • INFO[out]

    INFO is INTEGER

    = 0: successful exit

    < 0: if INFO = -i, the i-th argument had an illegal value