ungrq#

Functions

void cungrq(
    const INT           m,
    const INT           n,
    const INT           k,
          c64* restrict A,
    const INT           lda,
    const c64* restrict tau,
          c64* restrict work,
    const INT           lwork,
          INT*          info
);
void cungrq(const INT m, const INT n, const INT k, c64 *restrict A, const INT lda, const c64 *restrict tau, c64 *restrict work, const INT lwork, INT *info)#

CUNGRQ generates an M-by-N complex matrix Q with orthonormal rows, which is defined as the last M rows of a product of K elementary reflectors of order N.

Q = H(0)**H H(1)**H … H(k-1)**H

as returned by CGERQF.

This is the blocked Level 3 BLAS version of the algorithm.

Parameters

in
m

The number of rows of Q. m >= 0.

in
n

The number of columns of Q. n >= m.

in
k

The number of elementary reflectors whose product defines Q. m >= k >= 0.

inout
A

On entry, the (m-k+i)-th row must contain the vector which defines the elementary reflector H(i), for i = 0,…,k-1, as returned by CGERQF. On exit, the m-by-n matrix Q.

in
lda

The leading dimension of A. lda >= max(1, m).

in
tau

Array of dimension (k). TAU(i) is the scalar factor of H(i), as returned by CGERQF.

out
work

Workspace, dimension (max(1, lwork)). On exit, work[0] contains the optimal lwork.

in
lwork

Dimension of work. lwork >= max(1, m). For optimal performance, lwork >= m*nb. If lwork == -1, workspace query only.

out
info

  • = 0: successful exit

  • < 0: if info = -i, the i-th argument had an illegal value.

Functions

void zungrq(
    const INT            m,
    const INT            n,
    const INT            k,
          c128* restrict A,
    const INT            lda,
    const c128* restrict tau,
          c128* restrict work,
    const INT            lwork,
          INT*           info
);
void zungrq(const INT m, const INT n, const INT k, c128 *restrict A, const INT lda, const c128 *restrict tau, c128 *restrict work, const INT lwork, INT *info)#

ZUNGRQ generates an M-by-N complex matrix Q with orthonormal rows, which is defined as the last M rows of a product of K elementary reflectors of order N.

Q = H(0)**H H(1)**H … H(k-1)**H

as returned by ZGERQF.

This is the blocked Level 3 BLAS version of the algorithm.

Parameters

in
m

The number of rows of Q. m >= 0.

in
n

The number of columns of Q. n >= m.

in
k

The number of elementary reflectors whose product defines Q. m >= k >= 0.

inout
A

On entry, the (m-k+i)-th row must contain the vector which defines the elementary reflector H(i), for i = 0,…,k-1, as returned by ZGERQF. On exit, the m-by-n matrix Q.

in
lda

The leading dimension of A. lda >= max(1, m).

in
tau

Array of dimension (k). TAU(i) is the scalar factor of H(i), as returned by ZGERQF.

out
work

Workspace, dimension (max(1, lwork)). On exit, work[0] contains the optimal lwork.

in
lwork

Dimension of work. lwork >= max(1, m). For optimal performance, lwork >= m*nb. If lwork == -1, workspace query only.

out
info

  • = 0: successful exit

  • < 0: if info = -i, the i-th argument had an illegal value.

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