Developer Reference for Intel® oneAPI Math Kernel Library for C
?hemm
Computes a matrix-matrix product where one input matrix is Hermitian.
Syntax
void cblas_chemm(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_zhemm(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 ?hemm routines compute a scalar-matrix-matrix product using a Hermitian matrix A and a general matrix B and add the result to a scalar-matrix product using a general matrix C . 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 Hermitian 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 Hermitian matrix A appears on the left or right in the operation as follows:
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 Hermitian matrix A is used:
If uplo = CblasUpper , then the upper triangular part of the Hermitian matrix A is used.
If uplo = CblasLower , then the low triangular part of the Hermitian matrix A 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
-
COMPLEX for chemm DOUBLE COMPLEX for zhemm Specifies the scalar alpha .
- a
-
COMPLEX for chemm DOUBLE COMPLEX for zhemm
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 Hermitian 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 Hermitian matrix and the strictly lower triangular part of a is not referenced, and when uplo = CblasLower , the leading m -by- m lower triangular part of the array a must contain the lower triangular part of the Hermitian 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 Hermitian matrix, such that when uplo = CblasUpper , the leading n -by- n upper triangular part of the array a must contain the upper triangular part of the Hermitian matrix and the strictly lower triangular part of a is not referenced, and when uplo = CblasLower , the leading n -by- n lower triangular part of the array a must contain the lower triangular part of the Hermitian matrix, and the strictly upper triangular part of a is not referenced. The imaginary parts of the diagonal elements need not be set, they are assumed to be zero.
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
-
COMPLEX for chemm DOUBLE COMPLEX for zhemm 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
-
COMPLEX for chemm DOUBLE COMPLEX for zhemm Specifies the scalar beta . When beta is supplied as zero, then c need not be set on input.
- c
-
COMPLEX for chemm DOUBLE COMPLEX for zhemm 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.