NAME csyrk - perform one of the symmetric rank k operations C := alpha*A*A' + beta*C or C := alpha*A'*A + beta*C SYNOPSIS SUBROUTINE CSYRK ( UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C, LDC ) CHARACTER*1 UPLO, TRANS INTEGER N, K, LDA, LDC COMPLEX ALPHA, BETA COMPLEX A( LDA, * ), C( LDC, * ) #include <sunperf.h> void csyrk(char uplo, char trans, int n, int k, complex *calpha, complex *ca, int lda, complex *cbeta, complex *cc, int ldc) ; PURPOSE CSYRK performs one of the symmetric rank k operations C := alpha*A*A' + beta*C or C := alpha*A'*A + beta*C where alpha and beta are scalars, C is an n by n symmetric matrix and A is an n by k matrix in the first case and a k by n matrix in the second case. PARAMETERS UPLO - CHARACTER*1. On entry, UPLO specifies whether the upper or lower triangular part of the array C is to be referenced as follows: UPLO = 'U' or 'u' Only the upper triangular part of C is to be referenced. UPLO = 'L' or 'l' Only the lower triangular part of C is to be referenced. Unchanged on exit. TRANS - CHARACTER*1. On entry, TRANS specifies the operation to be performed as follows: TRANS = 'N' or 'n' C := alpha*A*A' + beta*C. TRANS = 'T' or 't' C := alpha*A'*A + beta*C. Unchanged on exit. N - INTEGER. On entry, N specifies the order of the matrix C. N must be at least zero. Unchanged on exit. K - INTEGER. On entry with TRANS = 'N' or 'n', K specifies the number of columns of the matrix A, and on entry with TRANS = 'T' or 't', K specifies the number of rows of the matrix A. K must be at least zero. Unchanged on exit. ALPHA - COMPLEX . On entry, ALPHA specifies the scalar alpha. Unchanged on exit. A - COMPLEX array of DIMENSION ( LDA, ka ), where ka is k when TRANS = 'N' or 'n', and is n other- wise. Before entry with TRANS = 'N' or 'n', the leading n by k part of the array A must contain the matrix A, otherwise the leading k by n part of the array A must contain the matrix A. Unchanged on exit. LDA - INTEGER. On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. When TRANS = 'N' or 'n' then LDA must be at least max( 1, n ), otherwise LDA must be at least max( 1, k ). Unchanged on exit. BETA - COMPLEX . On entry, BETA specifies the scalar beta. Unchanged on exit. C - COMPLEX array of DIMENSION ( LDC, n ). Before entry with UPLO = 'U' or 'u', the lead- ing n by n upper triangular part of the array C must contain the upper triangular part of the symmetric matrix and the strictly lower triangu- lar part of C is not referenced. On exit, the upper triangular part of the array C is overwrit- ten by the upper triangular part of the updated matrix. Before entry with UPLO = 'L' or 'l', the lead- ing n by n lower triangular part of the array C must contain the lower triangular part of the symmetric matrix and the strictly upper triangu- lar part of C is not referenced. On exit, the lower triangular part of the array C is overwrit- ten by the lower triangular part of the updated matrix. LDC - INTEGER. On entry, LDC specifies the first dimension of C as declared in the calling (sub) program. LDC must be at least max( 1, n ). Unchanged on exit.
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