# rocsolver_slasyf Interface Reference#

HIPFORT API Reference: hipfort_rocsolver::rocsolver_slasyf Interface Reference
hipfort_rocsolver::rocsolver_slasyf Interface Reference

LASYF computes a partial factorization of a symmetric matrix $$A$$ using Bunch-Kaufman diagonal pivoting. More...

## Public Member Functions

integer(kind(rocblas_status_success)) function rocsolver_slasyf_ (handle, uplo, n, nb, kb, A, lda, ipiv, myInfo)

integer(kind(rocblas_status_success)) function rocsolver_slasyf_full_rank (handle, uplo, n, nb, kb, A, lda, ipiv, myInfo)

integer(kind(rocblas_status_success)) function rocsolver_slasyf_rank_0 (handle, uplo, n, nb, kb, A, lda, ipiv, myInfo)

integer(kind(rocblas_status_success)) function rocsolver_slasyf_rank_1 (handle, uplo, n, nb, kb, A, lda, ipiv, myInfo)

## Detailed Description

LASYF computes a partial factorization of a symmetric matrix $$A$$ using Bunch-Kaufman diagonal pivoting.

The partial factorization has the form

$A = \left[ \begin{array}{cc} I & U_{12} \newline 0 & U_{22} \end{array} \right] \left[ \begin{array}{cc} A_{11} & 0 \newline 0 & D \end{array} \right] \left[ \begin{array}{cc} I & 0 \newline U_{12}^T & U_{22}^T \end{array} \right]$

or

$A = \left[ \begin{array}{cc} L_{11} & 0 \newline L_{21} & I \end{array} \right] \left[ \begin{array}{cc} D & 0 \newline 0 & A_{22} \end{array} \right] \left[ \begin{array}{cc} L_{11}^T & L_{21}^T \newline 0 & I \end{array} \right]$

depending on the value of uplo. The order of the block diagonal matrix $$D$$ is either $$nb$$ or $$nb-1$$, and is returned in the argument $$kb$$.

Parameters
 [in] handle rocblas_handle. [in] uplo rocblas_fill. Specifies whether the upper or lower part of the matrix A is stored. If uplo indicates lower (or upper), then the upper (or lower) part of A is not used. [in] n rocblas_int. n >= 0. The number of rows and columns of the matrix A. [in] nb rocblas_int. 2 <= nb <= n. The number of columns of A to be factored. [out] kb pointer to a rocblas_int on the GPU. The number of columns of A that were actually factored (either nb or nb-1). [in,out] A pointer to type. Array on the GPU of dimension lda*n. On entry, the symmetric matrix A to be factored. On exit, the partially factored matrix. [in] lda rocblas_int. lda >= n. Specifies the leading dimension of A. [out] ipiv pointer to rocblas_int. Array on the GPU of dimension n. The vector of pivot indices. Elements of ipiv are 1-based indices. If uplo is upper, then only the last kb elements of ipiv will be set. For n - kb < k <= n, if ipiv[k] > 0 then rows and columns k and ipiv[k] were interchanged and D[k,k] is a 1-by-1 diagonal block. If, instead, ipiv[k] = ipiv[k-1] < 0, then rows and columns k-1 and -ipiv[k] were interchanged and D[k-1,k-1] to D[k,k] is a 2-by-2 diagonal block. If uplo is lower, then only the first kb elements of ipiv will be set. For 1 <= k <= kb, if ipiv[k] > 0 then rows and columns k and ipiv[k] were interchanged and D[k,k] is a 1-by-1 diagonal block. If, instead, ipiv[k] = ipiv[k+1] < 0, then rows and columns k+1 and -ipiv[k] were interchanged and D[k,k] to D[k+1,k+1] is a 2-by-2 diagonal block. [out] info pointer to a rocblas_int on the GPU. If info = 0, successful exit. If info[i] = j > 0, D is singular. D[j,j] is the first diagonal zero.

## ◆ rocsolver_slasyf_()

 integer(kind(rocblas_status_success)) function hipfort_rocsolver::rocsolver_slasyf::rocsolver_slasyf_ ( type(c_ptr), value handle, integer(kind(rocblas_fill_upper)), value uplo, integer(c_int), value n, integer(c_int), value nb, type(c_ptr), value kb, type(c_ptr), value A, integer(c_int), value lda, type(c_ptr), value ipiv, integer(c_int) myInfo )

## ◆ rocsolver_slasyf_full_rank()

 integer(kind(rocblas_status_success)) function hipfort_rocsolver::rocsolver_slasyf::rocsolver_slasyf_full_rank ( type(c_ptr) handle, integer(kind(rocblas_fill_upper)) uplo, integer(c_int) n, integer(c_int) nb, type(c_ptr) kb, real(c_float), dimension(:,:), target A, integer(c_int) lda, integer(c_int), dimension(:), target ipiv, integer(c_int) myInfo )

## ◆ rocsolver_slasyf_rank_0()

 integer(kind(rocblas_status_success)) function hipfort_rocsolver::rocsolver_slasyf::rocsolver_slasyf_rank_0 ( type(c_ptr) handle, integer(kind(rocblas_fill_upper)) uplo, integer(c_int) n, integer(c_int) nb, type(c_ptr) kb, real(c_float), target A, integer(c_int) lda, integer(c_int), target ipiv, integer(c_int) myInfo )

## ◆ rocsolver_slasyf_rank_1()

 integer(kind(rocblas_status_success)) function hipfort_rocsolver::rocsolver_slasyf::rocsolver_slasyf_rank_1 ( type(c_ptr) handle, integer(kind(rocblas_fill_upper)) uplo, integer(c_int) n, integer(c_int) nb, type(c_ptr) kb, real(c_float), dimension(:), target A, integer(c_int) lda, integer(c_int), dimension(:), target ipiv, integer(c_int) myInfo )

The documentation for this interface was generated from the following file: