/**
Purpose
-------
ZPOTRI computes the inverse of a real symmetric positive definite
matrix A using the Cholesky factorization A = U**T*U or A = L*L**T
computed by ZPOTRF.
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,out]
dA COMPLEX_16 array on the GPU, dimension (LDA,N)
On entry, the triangular factor U or L from the Cholesky
factorization A = U**T*U or A = L*L**T, as computed by
ZPOTRF.
On exit, the upper or lower triangle of the (symmetric)
inverse of A, overwriting the input factor U or L.
@param[in]
ldda INTEGER
The leading dimension of the array dA. LDDA >= max(1,N).
@param[out]
info INTEGER
- = 0: successful exit
- < 0: if INFO = -i, the i-th argument had an illegal value
- > 0: if INFO = i, the (i,i) element of the factor U or L is
zero, and the inverse could not be computed.
@ingroup magma_zposv_comp
********************************************************************/
extern "C" magma_int_t
magma_zpotri_gpu(magma_uplo_t uplo, magma_int_t n,
magmaDoubleComplex *dA, magma_int_t ldda, magma_int_t *info)
{
/* Local variables */
*info = 0;
if ((uplo != MagmaUpper) && (uplo != MagmaLower))
*info = -1;
else if (n < 0)
*info = -2;
else if (ldda < max(1,n))
*info = -4;
if (*info != 0) {
magma_xerbla( __func__, -(*info) );
return *info;
}
/* Quick return if possible */
if ( n == 0 )
return *info;
/* Invert the triangular Cholesky factor U or L */
magma_ztrtri_gpu( uplo, MagmaNonUnit, n, dA, ldda, info );
if ( *info == 0 ) {
/* Form inv(U) * inv(U)**T or inv(L)**T * inv(L) */
magma_zlauum_gpu( uplo, n, dA, ldda, info );
}
return *info;
} /* magma_zpotri */
/**
Purpose
-------
ZGETRI computes the inverse of a matrix using the LU factorization
computed by ZGETRF. This method inverts U and then computes inv(A) by
solving the system inv(A)*L = inv(U) for inv(A).
Note that it is generally both faster and more accurate to use ZGESV,
or ZGETRF and ZGETRS, to solve the system AX = B, rather than inverting
the matrix and multiplying to form X = inv(A)*B. Only in special
instances should an explicit inverse be computed with this routine.
Arguments
---------
@param[in]
n INTEGER
The order of the matrix A. N >= 0.
@param[in,out]
dA COMPLEX_16 array on the GPU, dimension (LDDA,N)
On entry, the factors L and U from the factorization
A = P*L*U as computed by ZGETRF_GPU.
On exit, if INFO = 0, the inverse of the original matrix A.
@param[in]
ldda INTEGER
The leading dimension of the array A. LDDA >= max(1,N).
@param[in]
ipiv INTEGER array, dimension (N)
The pivot indices from ZGETRF; for 1 <= i <= N, row i of the
matrix was interchanged with row IPIV(i).
@param[out]
dwork (workspace) COMPLEX_16 array on the GPU, dimension (MAX(1,LWORK))
@param[in]
lwork INTEGER
The dimension of the array DWORK. LWORK >= N*NB, where NB is
the optimal blocksize returned by magma_get_zgetri_nb(n).
\n
Unlike LAPACK, this version does not currently support a
workspace query, because the workspace is on the GPU.
@param[out]
info INTEGER
- = 0: successful exit
- < 0: if INFO = -i, the i-th argument had an illegal value
- > 0: if INFO = i, U(i,i) is exactly zero; the matrix is
singular and its cannot be computed.
@ingroup magma_zgesv_comp
********************************************************************/
extern "C" magma_int_t
magma_zgetri_gpu( magma_int_t n, magmaDoubleComplex *dA, magma_int_t ldda,
magma_int_t *ipiv, magmaDoubleComplex *dwork, magma_int_t lwork,
magma_int_t *info )
{
#define dA(i, j) (dA + (i) + (j)*ldda)
#define dL(i, j) (dL + (i) + (j)*lddl)
/* Local variables */
magmaDoubleComplex c_zero = MAGMA_Z_ZERO;
magmaDoubleComplex c_one = MAGMA_Z_ONE;
magmaDoubleComplex c_neg_one = MAGMA_Z_NEG_ONE;
magmaDoubleComplex *dL = dwork;
magma_int_t lddl = n;
magma_int_t nb = magma_get_zgetri_nb(n);
magma_int_t j, jmax, jb, jp;
*info = 0;
if (n < 0)
*info = -1;
else if (ldda < max(1,n))
*info = -3;
else if ( lwork < n*nb )
*info = -6;
if (*info != 0) {
magma_xerbla( __func__, -(*info) );
return *info;
}
/* Quick return if possible */
if ( n == 0 )
return *info;
/* Invert the triangular factor U */
magma_ztrtri_gpu( MagmaUpper, MagmaNonUnit, n, dA, ldda, info );
if ( *info != 0 )
return *info;
jmax = ((n-1) / nb)*nb;
for( j = jmax; j >= 0; j -= nb ) {
jb = min( nb, n-j );
// copy current block column of A to work space dL
// (only needs lower trapezoid, but we also copy upper triangle),
// then zero the strictly lower trapezoid block column of A.
magmablas_zlacpy( MagmaFull, n-j, jb,
dA(j,j), ldda,
dL(j,0), lddl );
magmablas_zlaset( MagmaLower, n-j-1, jb, c_zero, c_zero, dA(j+1,j), ldda );
// compute current block column of Ainv
// Ainv(:, j:j+jb-1)
// = ( U(:, j:j+jb-1) - Ainv(:, j+jb:n) L(j+jb:n, j:j+jb-1) )
// * L(j:j+jb-1, j:j+jb-1)^{-1}
// where L(:, j:j+jb-1) is stored in dL.
if ( j+jb < n ) {
magma_zgemm( MagmaNoTrans, MagmaNoTrans, n, jb, n-j-jb,
c_neg_one, dA(0,j+jb), ldda,
dL(j+jb,0), lddl,
c_one, dA(0,j), ldda );
}
// TODO use magmablas work interface
magma_ztrsm( MagmaRight, MagmaLower, MagmaNoTrans, MagmaUnit,
n, jb, c_one,
dL(j,0), lddl,
dA(0,j), ldda );
}
// Apply column interchanges
for( j = n-2; j >= 0; --j ) {
jp = ipiv[j] - 1;
if ( jp != j ) {
magmablas_zswap( n, dA(0,j), 1, dA(0,jp), 1 );
}
}
return *info;
}
extern "C" magma_int_t
magma_zpotri_gpu(magma_uplo_t uplo, magma_int_t n,
magmaDoubleComplex_ptr a, size_t offset_a, magma_int_t lda, magma_int_t *info, magma_queue_t queue)
{
/* -- MAGMA (version 1.0.0) --
Univ. of Tennessee, Knoxville
Univ. of California, Berkeley
Univ. of Colorado, Denver
August 2012
Purpose
=======
ZPOTRI computes the inverse of a real symmetric positive definite
matrix A using the Cholesky factorization A = U**T*U or A = L*L**T
computed by ZPOTRF.
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.
A (input/output) COMPLEX_16 array, dimension (LDA,N)
On entry, the triangular factor U or L from the Cholesky
factorization A = U**T*U or A = L*L**T, as computed by
ZPOTRF.
On exit, the upper or lower triangle of the (symmetric)
inverse of A, overwriting the input factor U or L.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, the (i,i) element of the factor U or L is
zero, and the inverse could not be computed.
===================================================================== */
/* Local variables */
magma_uplo_t uplo_ = uplo;
*info = 0;
if ((! lapackf77_lsame(lapack_const(uplo_), lapack_const(MagmaUpper))) && (! lapackf77_lsame(lapack_const(uplo_), lapack_const(MagmaLower))))
*info = -1;
else if (n < 0)
*info = -2;
else if (lda < max(1,n))
*info = -4;
if (*info != 0) {
magma_xerbla( __func__, -(*info) );
return *info;
}
/* Quick return if possible */
if ( n == 0 )
return *info;
/* Invert the triangular Cholesky factor U or L */
magma_ztrtri_gpu( uplo, MagmaNonUnit, n, a, offset_a, lda, info );
if ( *info == 0 ) {
/* Form inv(U) * inv(U)**T or inv(L)**T * inv(L) */
magma_zlauum_gpu( uplo, n, a, offset_a, lda, info, queue );
}
return *info;
} /* magma_zpotri */