ungr2#

Functions

void cungr2(
    const INT           m,
    const INT           n,
    const INT           k,
          c64* restrict A,
    const INT           lda,
    const c64* restrict tau,
          c64* restrict work,
          INT*          info
);
void cungr2(const INT m, const INT n, const INT k, c64 *restrict A, const INT lda, const c64 *restrict tau, c64 *restrict work, INT *info)#

CUNGR2 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.

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 = 0,1,…,k-1, as returned by CGERQF in the last k rows of its array argument A. 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) must contain the scalar factor of the elementary reflector H(i), as returned by CGERQF.

out
work

Workspace, dimension (m).

out
info

  • = 0: successful exit

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

Functions

void zungr2(
    const INT            m,
    const INT            n,
    const INT            k,
          c128* restrict A,
    const INT            lda,
    const c128* restrict tau,
          c128* restrict work,
          INT*           info
);
void zungr2(const INT m, const INT n, const INT k, c128 *restrict A, const INT lda, const c128 *restrict tau, c128 *restrict work, INT *info)#

ZUNGR2 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.

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 = 0,1,…,k-1, as returned by ZGERQF in the last k rows of its array argument A. 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) must contain the scalar factor of the elementary reflector H(i), as returned by ZGERQF.

out
work

Workspace, dimension (m).

out
info

  • = 0: successful exit

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

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