Developer Reference for Intel® oneAPI Math Kernel Library for C
?symm
Computes a matrix-matrix product where one input matrix is symmetric.
Syntax
void cblas_ssymm(const CBLAS_LAYOUT Layout, const CBLAS_SIDE side, const CBLAS_UPLO uplo,
const MKL_INT m, const MKL_INT n, const float alpha, const float *a,
const MKL_INT lda, const float *b, const MKL_INT ldb, const float beta,
float *c, const MKL_INT ldc);
void cblas_dsymm(const CBLAS_LAYOUT Layout, const CBLAS_SIDE side, const CBLAS_UPLO uplo,
const MKL_INT m, const MKL_INT n, const double alpha, const double *a,
const MKL_INT lda, const double *b, const MKL_INT ldb, const double beta,
double *c, const MKL_INT ldc);
void cblas_csymm(const CBLAS_LAYOUT Layout, const CBLAS_SIDE side, const CBLAS_UPLO uplo,
const MKL_INT m, const MKL_INT n, const void *alpha, const void *a,
const MKL_INT lda, const void *b, const MKL_INT ldb, const void *beta,
void *c, const MKL_INT ldc);
void cblas_zsymm(const CBLAS_LAYOUT Layout, const CBLAS_SIDE side, const CBLAS_UPLO uplo,
const MKL_INT m, const MKL_INT n, const void *alpha, const void *a,
const MKL_INT lda, const void *b, const MKL_INT ldb, const void *beta,
void *c, const MKL_INT ldc);Include Files
mkl.h
Description
The ?symm routines compute a scalar-matrix-matrix product with one symmetric matrix and add the result to a scalar-matrix product . The operation is defined as C:=alpha * A * B+ beta * C ,
or C:=alpha * B * A+ beta * C ,
where:
alpha and beta are scalars,
A is a symmetric matrix,
B and C are m -by- n matrices.
Input Parameters
- Layout
-
Specifies whether two-dimensional array storage is row-major ( CblasRowMajor ) or column-major ( CblasColMajor ).
side
Specifies whether the symmetric matrix A appears on the left or right in the operation:
if side = CblasLeft , then C := alpha*A*B + beta*C ;
if side = CblasRight , then C := alpha*B*A + beta*C .
uplo
Specifies whether the upper or lower triangular part of the symmetric matrix A is used:
if uplo = CblasUpper , then the upper triangular part is used;
if uplo = CblasLower , then the lower triangular part is used.
- m
-
Specifies the number of rows of the matrix C .
The value of m must be at least zero.
- n
-
Specifies the number of columns of the matrix C .
The value of n must be at least zero.
- alpha
-
REAL for ssymm DOUBLE PRECISION for dsymm COMPLEX for csymm DOUBLE COMPLEX for zsymm Specifies the scalar alpha .
- a
-
REAL for ssymm DOUBLE PRECISION for dsymm COMPLEX for csymm DOUBLE COMPLEX for zsymm
Array, size (lda, ka)lda* ka , where ka is m when side = CblasLeft and is n otherwise.
Before entry with side = CblasLeft , the m -by- m part of the array a must contain the symmetric matrix, such that when uplo = CblasUpper , the leading m -by- m upper triangular part of the array a must contain the upper triangular part of the symmetric matrix and the strictly lower triangular part of a is not referenced, and when uplo = CblasLeft , the leading m -by- m lower triangular part of the array a must contain the lower triangular part of the symmetric matrix and the strictly upper triangular part of a is not referenced.
Before entry with side = CblasRight , the n -by- n part of the array a must contain the symmetric matrix, such that when uplo = CblasUpper e array a must contain the upper triangular part of the symmetric matrix and the strictly lower triangular part of a is not referenced, and when uplo = CblasLeft , the leading n -by- n lower triangular part of the array a must contain the lower triangular part of the symmetric matrix and the strictly upper triangular part of a is not referenced.
lda
Specifies the leading dimension of a as declared in the calling (sub)program. When side = CblasLeft then lda must be at least max(1, m) , otherwise lda must be at least max(1, n) .
- b
-
REAL for ssymm DOUBLE PRECISION for dsymm COMPLEX for csymm DOUBLE COMPLEX for zsymm Array, size ldb by n .
For Layout = CblasColMajor : array, size ldb * n . The leading m -by- n part of the array b must contain the matrix B .
For Layout = CblasRowMajor : array, size ldb * m . The leading n -by- m part of the array b must contain the matrix B
ldb
Specifies the leading dimension of b as declared in the calling (sub)program. When Layout = CblasColMajor , ldb must be at least max(1, m) ; otherwise, ldb must be at least max(1, n) .
- beta
-
REAL for ssymm DOUBLE PRECISION for dsymm COMPLEX for csymm DOUBLE COMPLEX for zsymm Specifies the scalar beta . When beta is set to zero, then c need not be set on input.
- c
-
REAL for ssymm DOUBLE PRECISION for dsymm COMPLEX for csymm DOUBLE COMPLEX for zsymm Array, size (c, n) . Before entry, the leading m -by- n part of the array c must contain the matrix C , except when beta is zero, in which case c need not be set on entry. For Layout = CblasColMajor : array, size ldc*n . Before entry, the leading m -by- n part of the array c must contain the matrix C , except when beta is zero, in which case c need not be set on entry. For Layout = CblasRowMajor : array, size ldc*m . Before entry, the leading n -by- m part of the array c must contain the matrix C , except when beta is zero, in which case c need not be set on entry.
ldc
Specifies the leading dimension of c as declared in the calling (sub)program. When Layout = CblasColMajor , ldc must be at least max(1, m) ; otherwise, ldc must be at least max(1, n) .
Output Parameters
- c
-
Overwritten by the m -by- n updated matrix.
BLAS 95 Interface Notes
There exist FORTRAN 77 and FORTRAN 95 interfaces for this routine. See the Intel® oneMKL Fortran Developer Reference for details.