getrf2#

Functions

void sgetrf2(
    const INT           m,
    const INT           n,
          f32* restrict A,
    const INT           lda,
          INT* restrict ipiv,
          INT*          info
);
void sgetrf2(const INT m, const INT n, f32 *restrict A, const INT lda, INT *restrict ipiv, INT *info)#

Computes an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges (recursive algorithm).

The factorization has the form: 

A = P * L * U
where P is a permutation matrix, L is lower triangular with unit diagonal elements, and U is upper triangular.

This is a recursive version that achieves better cache utilization than the iterative unblocked algorithm for medium-sized matrices. For small panels (n <= RECURSION_THRESHOLD), it falls back to the unblocked sgetf2.

Parameters

in
m

The number of rows of the matrix A (m >= 0).

in
n

The number of columns of the matrix A (n >= 0).

inout
A

On entry, the M-by-N matrix to be factored. On exit, the factors L and U from the factorization; the unit diagonal elements of L are not stored.

in
lda

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

out
ipiv

The pivot indices; row i was interchanged with row ipiv[i]. Array of dimension min(m,n), 0-based.

out
info

Exit status.

  • = 0: successful exit

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

  • > 0: if info = i, U(i-1,i-1) is exactly zero. The factorization has been completed, but U is exactly singular.

Functions

void dgetrf2(
    const INT           m,
    const INT           n,
          f64* restrict A,
    const INT           lda,
          INT* restrict ipiv,
          INT*          info
);
void dgetrf2(const INT m, const INT n, f64 *restrict A, const INT lda, INT *restrict ipiv, INT *info)#

Computes an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges (recursive algorithm).

The factorization has the form: 

A = P * L * U
where P is a permutation matrix, L is lower triangular with unit diagonal elements, and U is upper triangular.

This is a recursive version that achieves better cache utilization than the iterative unblocked algorithm for medium-sized matrices. For small panels (n <= RECURSION_THRESHOLD), it falls back to the unblocked dgetf2.

Parameters

in
m

The number of rows of the matrix A (m >= 0).

in
n

The number of columns of the matrix A (n >= 0).

inout
A

On entry, the M-by-N matrix to be factored. On exit, the factors L and U from the factorization; the unit diagonal elements of L are not stored.

in
lda

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

out
ipiv

The pivot indices; row i was interchanged with row ipiv[i]. Array of dimension min(m,n), 0-based.

out
info

Exit status.

  • = 0: successful exit

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

  • > 0: if info = i, U(i-1,i-1) is exactly zero. The factorization has been completed, but U is exactly singular.

Functions

void cgetrf2(
    const INT           m,
    const INT           n,
          c64* restrict A,
    const INT           lda,
          INT* restrict ipiv,
          INT*          info
);
void cgetrf2(const INT m, const INT n, c64 *restrict A, const INT lda, INT *restrict ipiv, INT *info)#

Computes an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges (recursive algorithm).

The factorization has the form: 

A = P * L * U
where P is a permutation matrix, L is lower triangular with unit diagonal elements, and U is upper triangular.

This is a recursive version that achieves better cache utilization than the iterative unblocked algorithm for medium-sized matrices. For small panels (n <= RECURSION_THRESHOLD), it falls back to the unblocked cgetf2.

Parameters

in
m

The number of rows of the matrix A (m >= 0).

in
n

The number of columns of the matrix A (n >= 0).

inout
A

On entry, the M-by-N matrix to be factored. On exit, the factors L and U from the factorization; the unit diagonal elements of L are not stored.

in
lda

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

out
ipiv

The pivot indices; row i was interchanged with row ipiv[i]. Array of dimension min(m,n), 0-based.

out
info

Exit status.

  • = 0: successful exit

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

  • > 0: if info = i, U(i-1,i-1) is exactly zero. The factorization has been completed, but U is exactly singular.

Functions

void zgetrf2(
    const INT            m,
    const INT            n,
          c128* restrict A,
    const INT            lda,
          INT*  restrict ipiv,
          INT*           info
);
void zgetrf2(const INT m, const INT n, c128 *restrict A, const INT lda, INT *restrict ipiv, INT *info)#

Computes an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges (recursive algorithm).

The factorization has the form: 

A = P * L * U
where P is a permutation matrix, L is lower triangular with unit diagonal elements, and U is upper triangular.

This is a recursive version that achieves better cache utilization than the iterative unblocked algorithm for medium-sized matrices. For small panels (n <= RECURSION_THRESHOLD), it falls back to the unblocked zgetf2.

Parameters

in
m

The number of rows of the matrix A (m >= 0).

in
n

The number of columns of the matrix A (n >= 0).

inout
A

On entry, the M-by-N matrix to be factored. On exit, the factors L and U from the factorization; the unit diagonal elements of L are not stored.

in
lda

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

out
ipiv

The pivot indices; row i was interchanged with row ipiv[i]. Array of dimension min(m,n), 0-based.

out
info

Exit status.

  • = 0: successful exit

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

  • > 0: if info = i, U(i-1,i-1) is exactly zero. The factorization has been completed, but U is exactly singular.