extern "C" magma_int_t
magma_sposv ( char uplo, magma_int_t n, magma_int_t nrhs,
float *A, magma_int_t lda,
float *B, magma_int_t ldb, magma_int_t *info )
{
/* -- MAGMA (version 1.4.0) --
Univ. of Tennessee, Knoxville
Univ. of California, Berkeley
Univ. of Colorado, Denver
August 2013
Purpose
=======
SPOSV computes the solution to a real system of linear equations
A * X = B,
where A is an N-by-N symmetric positive definite matrix and X and B
are N-by-NRHS matrices.
The Cholesky decomposition is used to factor A as
A = U**T * U, if UPLO = 'U', or
A = L * L**T, if UPLO = 'L',
where U is an upper triangular matrix and L is a lower triangular
matrix. The factored form of A is then used to solve the system of
equations A * X = B.
Arguments
=========
UPLO (input) CHARACTER*1
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
N (input) INTEGER
The order of the matrix A. N >= 0.
NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.
A (input/output) REAL array, dimension (LDA,N)
On entry, the symmetric matrix A. If UPLO = 'U', the leading
N-by-N upper triangular part of A contains the upper
triangular part of the matrix A, and the strictly lower
triangular part of A is not referenced. If UPLO = 'L', the
leading N-by-N lower triangular part of A contains the lower
triangular part of the matrix A, and the strictly upper
triangular part of A is not referenced.
On exit, if INFO = 0, the factor U or L from the Cholesky
factorization A = U**T*U or A = L*L**T.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
B (input/output) REAL array, dimension (LDB,NRHS)
On entry, the right hand side matrix B.
On exit, the solution matrix X.
LDB (input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
===================================================================== */
magma_int_t num_gpus, ldda, lddb;
*info = 0 ;
if( (uplo != 'U') && (uplo != 'u') && (uplo != 'L') && (uplo != 'l') )
*info = -1;
if( n < 0 )
*info = -2;
if( nrhs < 0)
*info = -3;
if ( lda < max(1, n) )
*info = -5;
if ( ldb < max(1, n) )
*info = -7;
if (*info != 0) {
magma_xerbla( __func__, -(*info) );
return *info;
}
/* Quick return if possible */
if ( (n==0) || (nrhs == 0) ) {
return *info;
}
/* If single-GPU and allocation suceeds, use GPU interface. */
num_gpus = magma_num_gpus();
float *dA, *dB;
if ( num_gpus > 1 ) {
goto CPU_INTERFACE;
}
ldda = ((n+31)/32)*32;
lddb = ldda;
if ( MAGMA_SUCCESS != magma_smalloc( &dA, ldda*n )) {
goto CPU_INTERFACE;
}
if ( MAGMA_SUCCESS != magma_smalloc( &dB, lddb*nrhs )) {
magma_free( dA );
goto CPU_INTERFACE;
}
magma_ssetmatrix( n, n, A, lda, dA, ldda );
magma_spotrf_gpu( uplo, n, dA, ldda, info );
if ( *info == MAGMA_ERR_DEVICE_ALLOC ) {
magma_free( dA );
magma_free( dB );
goto CPU_INTERFACE;
}
magma_sgetmatrix( n, n, dA, ldda, A, lda );
if ( *info == 0 ) {
magma_ssetmatrix( n, nrhs, B, ldb, dB, lddb );
magma_spotrs_gpu( uplo, n, nrhs, dA, ldda, dB, lddb, info );
magma_sgetmatrix( n, nrhs, dB, lddb, B, ldb );
}
magma_free( dA );
magma_free( dB );
return *info;
CPU_INTERFACE:
/* If multi-GPU or allocation failed, use CPU interface and LAPACK.
* Faster to use LAPACK for potrs than to copy A to GPU. */
magma_spotrf( uplo, n, A, lda, info );
if ( *info == 0 ) {
lapackf77_spotrs( &uplo, &n, &nrhs, A, &lda, B, &ldb, info );
}
return *info;
}
/**
Purpose
-------
SPOSV computes the solution to a real system of linear equations
A * X = B,
where A is an N-by-N symmetric positive definite matrix and X and B
are N-by-NRHS matrices.
The Cholesky decomposition is used to factor A as
A = U**H * U, if UPLO = MagmaUpper, or
A = L * L**H, if UPLO = MagmaLower,
where U is an upper triangular matrix and L is a lower triangular
matrix. The factored form of A is then used to solve the system of
equations A * X = B.
Arguments
---------
@param[in]
uplo magma_uplo_t
- = MagmaUpper: Upper triangle of A is stored;
- = MagmaLower: Lower triangle of A is stored.
@param[in]
n INTEGER
The order of the matrix A. N >= 0.
@param[in]
nrhs INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.
@param[in,out]
A REAL array, dimension (LDA,N)
On entry, the symmetric matrix A. If UPLO = MagmaUpper, the leading
N-by-N upper triangular part of A contains the upper
triangular part of the matrix A, and the strictly lower
triangular part of A is not referenced. If UPLO = MagmaLower, the
leading N-by-N lower triangular part of A contains the lower
triangular part of the matrix A, and the strictly upper
triangular part of A is not referenced.
\n
On exit, if INFO = 0, the factor U or L from the Cholesky
factorization A = U**H*U or A = L*L**H.
@param[in]
lda INTEGER
The leading dimension of the array A. LDA >= max(1,N).
@param[in,out]
B REAL array, dimension (LDB,NRHS)
On entry, the right hand side matrix B.
On exit, the solution matrix X.
@param[in]
ldb INTEGER
The leading dimension of the array B. LDB >= max(1,N).
@param[out]
info INTEGER
- = 0: successful exit
- < 0: if INFO = -i, the i-th argument had an illegal value
@ingroup magma_sposv_driver
********************************************************************/
extern "C" magma_int_t
magma_sposv(
magma_uplo_t uplo, magma_int_t n, magma_int_t nrhs,
float *A, magma_int_t lda,
float *B, magma_int_t ldb,
magma_int_t *info )
{
magma_int_t ngpu, ldda, lddb;
*info = 0;
if ( uplo != MagmaUpper && uplo != MagmaLower )
*info = -1;
if ( n < 0 )
*info = -2;
if ( nrhs < 0)
*info = -3;
if ( lda < max(1, n) )
*info = -5;
if ( ldb < max(1, n) )
*info = -7;
if (*info != 0) {
magma_xerbla( __func__, -(*info) );
return *info;
}
/* Quick return if possible */
if ( (n == 0) || (nrhs == 0) ) {
return *info;
}
/* If single-GPU and allocation suceeds, use GPU interface. */
ngpu = magma_num_gpus();
float *dA, *dB;
if ( ngpu > 1 ) {
goto CPU_INTERFACE;
}
ldda = ((n+31)/32)*32;
lddb = ldda;
if ( MAGMA_SUCCESS != magma_smalloc( &dA, ldda*n )) {
goto CPU_INTERFACE;
}
if ( MAGMA_SUCCESS != magma_smalloc( &dB, lddb*nrhs )) {
magma_free( dA );
goto CPU_INTERFACE;
}
magma_ssetmatrix( n, n, A, lda, dA, ldda );
magma_spotrf_gpu( uplo, n, dA, ldda, info );
if ( *info == MAGMA_ERR_DEVICE_ALLOC ) {
magma_free( dA );
magma_free( dB );
goto CPU_INTERFACE;
}
magma_sgetmatrix( n, n, dA, ldda, A, lda );
if ( *info == 0 ) {
magma_ssetmatrix( n, nrhs, B, ldb, dB, lddb );
magma_spotrs_gpu( uplo, n, nrhs, dA, ldda, dB, lddb, info );
magma_sgetmatrix( n, nrhs, dB, lddb, B, ldb );
}
magma_free( dA );
magma_free( dB );
return *info;
CPU_INTERFACE:
/* If multi-GPU or allocation failed, use CPU interface and LAPACK.
* Faster to use LAPACK for potrs than to copy A to GPU. */
magma_spotrf( uplo, n, A, lda, info );
if ( *info == 0 ) {
lapackf77_spotrs( lapack_uplo_const(uplo), &n, &nrhs, A, &lda, B, &ldb, info );
}
return *info;
}
