Developer Reference for Intel® oneAPI Math Kernel Library for C
p?syrk
Performs a rank-k update of a symmetric distributed matrix.
Syntax
void pssyrk(const char *uplo, const char *trans, const MKL_INT *n, const MKL_INT *k,
const float *alpha, const float *a, const MKL_INT *ia, const MKL_INT *ja,
const MKL_INT *desca, const float *beta, float *c, const MKL_INT *ic,
const MKL_INT *jc, const MKL_INT *descc);
void pdsyrk(const char *uplo, const char *trans, const MKL_INT *n, const MKL_INT *k,
const double *alpha, const double *a, const MKL_INT *ia, const MKL_INT *ja,
const MKL_INT *desca, const double *beta, double *c, const MKL_INT *ic,
const MKL_INT *jc, const MKL_INT *descc);
void pcsyrk(const char *uplo, const char *trans, const MKL_INT *n, const MKL_INT *k,
const MKL_Complex8 *alpha, const MKL_Complex8 *a, const MKL_INT *ia,
const MKL_INT *ja, const MKL_INT *desca, const MKL_Complex8 *beta,
MKL_Complex8 *c, const MKL_INT *ic, const MKL_INT *jc, const MKL_INT *descc);
void pzsyrk(const char *uplo, const char *trans, const MKL_INT *n, const MKL_INT *k,
const MKL_Complex16 *alpha, const MKL_Complex16 *a, const MKL_INT *ia,
const MKL_INT *ja, const MKL_INT *desca, const MKL_Complex16 *beta,
MKL_Complex16 *c, const MKL_INT *ic, const MKL_INT *jc, const MKL_INT *descc);Include Files
mkl_pblas.h
Description
The p?syrk routines perform a distributed matrix-matrix operation defined as sub( C ):= alpha *sub( A )*sub( A )’+ beta *sub( C ),
or sub( C ):= alpha *sub( A )’*sub( A )+ beta *sub( C ),
where:
alpha and beta are scalars,
sub(C) is an n -by- n symmetric distributed matrix, sub(C)=C(ic:ic+n-1, jc:jc+n-1) .
sub(A) is a distributed matrix, sub(A)=A(ia:ia+n-1, ja:ja+k-1) , if trans = 'N' or 'n' , and sub(A)=A(ia:ia+k-1, ja:ja+n-1) otherwise.
Input Parameters
uplo
(global) Specifies whether the upper or lower triangular part of the symmetric distributed matrix sub(C) is used:
If uplo = 'U' or ‘u’ , then the upper triangular part of the sub(C) is used. If uplo = 'L' or ‘l’ , then the low triangular part of the sub(C) is used.
trans
(global) Specifies the operation:
if trans = 'N' or 'n' , then sub(C) := alpha*sub(A)*sub(A)' + beta*sub(C) ; if trans = 'T' or 't' , then sub(C) := alpha*sub(A)'*sub(A) + beta*sub(C) .
n
(global) Specifies the order of the distributed matrix sub(C) , n ≥ 0.
k
(global) On entry with trans = 'N' or ‘n’ , k specifies the number of columns of the distributed matrix sub(A) , and on entry with trans = 'T' or ‘t’ , k specifies the number of rows of the distributed matrix sub(A) , k ≥ 0.
alpha
(global)
DOUBLE PRECISION for pdsyrk COMPLEX for pcsyrk DOUBLE COMPLEX for pzsyrk Specifies the scalar alpha .
a
(local)
DOUBLE PRECISION for pdsyrk COMPLEX for pcsyrk DOUBLE COMPLEX for pzsyrk Array, size (lld_a, kla) , where kla is LOCq(ja+k-1) when trans = 'N' or ‘n’ , and is LOCq(ja+n-1) otherwise. Before entry with trans = 'N' or ‘n’ , this array contains the local pieces of the distributed matrix sub(A) .
ia , ja
(global) The row and column indices in the distributed matrix A indicating the first row and the first column of the submatrix sub(A) , respectively.
desca
(global and local) array of dimension 9. The array descriptor of the distributed matrix A .
beta
(global)
DOUBLE PRECISION for pdsyrk COMPLEX for pcsyrk DOUBLE COMPLEX for pzsyrk Specifies the scalar beta .
c
(local)
DOUBLE PRECISION for pdsyrk COMPLEX for pcsyrk DOUBLE COMPLEX for pzsyrk Array, size (lld_c, LOCq(jc+n-1)) . Before entry with uplo = 'U' or ‘u’ , this array contains n -by- n upper triangular part of the symmetric distributed matrix sub(C) and its strictly lower triangular part is not referenced. Before entry with uplo = 'L' or ‘l’ , this array contains n -by- n lower triangular part of the symmetric distributed matrix sub(C) and its strictly upper triangular part is not referenced.
ic , jc
(global) The row and column indices in the distributed matrix C indicating the first row and the first column of the submatrix sub(C) , respectively.
descc
(global and local) array of dimension 9. The array descriptor of the distributed matrix C .
Output Parameters
- c
-
With uplo = 'U' or ‘u’ , the upper triangular part of sub(C) is overwritten by the upper triangular part of the updated distributed matrix. With uplo = 'L' or ‘l’ , the lower triangular part of sub(C) is overwritten by the upper triangular part of the updated distributed matrix.