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MAN page from openSUSE Leap 42 blas-man-3.5.0-9.1.noarch.rpm
csyr2k.fSection: LAPACK (3) Updated: Fri Nov 4 2016 Index NAMEcsyr2k.f - SYNOPSIS Functions/Subroutines
subroutine CSYR2K (UPLO, TRANS, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
CSYR2K
Function/Subroutine Documentation subroutine CSYR2K (character UPLO, character TRANS, integer N, integer K, complex ALPHA, complex, dimension(lda,*) A, integer LDA, complex, dimension(ldb,*) B, integer LDB, complex BETA, complex, dimension(ldc,*) C, integer LDC)CSYR2K Purpose: CSYR2K performs one of the symmetric rank 2k operations C := alpha*A*B**T + alpha*B*A**T + beta*C, or C := alpha*A**T*B + alpha*B**T*A + beta*C, where alpha and beta are scalars, C is an n by n symmetric matrix and A and B are n by k matrices in the first case and k by n matrices in the second case.
Parameters: - UPLO
UPLO is 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.
TRANS
TRANS is CHARACTER*1 On entry, TRANS specifies the operation to be performed as follows: TRANS = 'N' or 'n' C := alpha*A*B**T + alpha*B*A**T + beta*C. TRANS = 'T' or 't' C := alpha*A**T*B + alpha*B**T*A + beta*C.
N
N is INTEGER On entry, N specifies the order of the matrix C. N must be at least zero.
K
K is INTEGER On entry with TRANS = 'N' or 'n', K specifies the number of columns of the matrices A and B, and on entry with TRANS = 'T' or 't', K specifies the number of rows of the matrices A and B. K must be at least zero.
ALPHA
ALPHA is COMPLEX On entry, ALPHA specifies the scalar alpha.
A
A is COMPLEX array of DIMENSION ( LDA, ka ), where ka is k when TRANS = 'N' or 'n', and is n otherwise. 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.
LDA
LDA is 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 ).
B
B is COMPLEX array of DIMENSION ( LDB, kb ), where kb is k when TRANS = 'N' or 'n', and is n otherwise. Before entry with TRANS = 'N' or 'n', the leading n by k part of the array B must contain the matrix B, otherwise the leading k by n part of the array B must contain the matrix B.
LDB
LDB is INTEGER On entry, LDB specifies the first dimension of B as declared in the calling (sub) program. When TRANS = 'N' or 'n' then LDB must be at least max( 1, n ), otherwise LDB must be at least max( 1, k ).
BETA
BETA is COMPLEX On entry, BETA specifies the scalar beta.
C
C is COMPLEX array of DIMENSION ( LDC, n ). Before entry with UPLO = 'U' or 'u', the leading n by n upper triangular part of the array C must contain the upper triangular part of the symmetric matrix and the strictly lower triangular part of C is not referenced. On exit, the upper triangular part of the array C is overwritten by the upper triangular part of the updated matrix. Before entry with UPLO = 'L' or 'l', the leading n by n lower triangular part of the array C must contain the lower triangular part of the symmetric matrix and the strictly upper triangular part of C is not referenced. On exit, the lower triangular part of the array C is overwritten by the lower triangular part of the updated matrix.
LDC
LDC is 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 ).
Author: - Univ. of Tennessee
Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd.
Date: - November 2011
Further Details: Level 3 Blas routine. -- Written on 8-February-1989. Jack Dongarra, Argonne National Laboratory. Iain Duff, AERE Harwell. Jeremy Du Croz, Numerical Algorithms Group Ltd. Sven Hammarling, Numerical Algorithms Group Ltd.
Definition at line 190 of file csyr2k.f. 190 *191 * -- Reference BLAS level3 routine (version 3.4.0) --192 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --193 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--194 * November 2011195 *196 * .. Scalar Arguments ..197 COMPLEX alpha,beta198 INTEGER k,lda,ldb,ldc,n199 CHARACTER trans,uplo200 * ..201 * .. Array Arguments ..202 COMPLEX a(lda,*),b(ldb,*),c(ldc,*)203 * ..204 *205 * =====================================================================206 *207 * .. External Functions ..208 LOGICAL lsame209 EXTERNAL lsame210 * ..211 * .. External Subroutines ..212 EXTERNAL xerbla213 * ..214 * .. Intrinsic Functions ..215 INTRINSIC max216 * ..217 * .. Local Scalars ..218 COMPLEX temp1,temp2219 INTEGER i,info,j,l,nrowa220 LOGICAL upper221 * ..222 * .. Parameters ..223 COMPLEX one224 parameter(one= (1.0e+0,0.0e+0))225 COMPLEX zero226 parameter(zero= (0.0e+0,0.0e+0))227 * ..228 *229 * Test the input parameters.230 *231 IF (lsame(trans,'N')) THEN232 nrowa = n233 ELSE234 nrowa = k235 END IF236 upper = lsame(uplo,'U')237 *238 info = 0239 IF ((.NOT.upper) .AND. (.NOT.lsame(uplo,'L'))) THEN240 info = 1241 ELSE IF ((.NOT.lsame(trans,'N')) .AND.242 + (.NOT.lsame(trans,'T'))) THEN243 info = 2244 ELSE IF (n.LT.0) THEN245 info = 3246 ELSE IF (k.LT.0) THEN247 info = 4248 ELSE IF (lda.LT.max(1,nrowa)) THEN249 info = 7250 ELSE IF (ldb.LT.max(1,nrowa)) THEN251 info = 9252 ELSE IF (ldc.LT.max(1,n)) THEN253 info = 12254 END IF255 IF (info.NE.0) THEN256 CALL xerbla('CSYR2K',info)257 RETURN258 END IF259 *260 * Quick return if possible.261 *262 IF ((n.EQ.0) .OR. (((alpha.EQ.zero).OR.263 + (k.EQ.0)).AND. (beta.EQ.one))) RETURN264 *265 * And when alpha.eq.zero.266 *267 IF (alpha.EQ.zero) THEN268 IF (upper) THEN269 IF (beta.EQ.zero) THEN270 DO 20 j = 1,n271 DO 10 i = 1,j272 c(i,j) = zero273 10 CONTINUE274 20 CONTINUE275 ELSE276 DO 40 j = 1,n277 DO 30 i = 1,j278 c(i,j) = beta*c(i,j)279 30 CONTINUE280 40 CONTINUE281 END IF282 ELSE283 IF (beta.EQ.zero) THEN284 DO 60 j = 1,n285 DO 50 i = j,n286 c(i,j) = zero287 50 CONTINUE288 60 CONTINUE289 ELSE290 DO 80 j = 1,n291 DO 70 i = j,n292 c(i,j) = beta*c(i,j)293 70 CONTINUE294 80 CONTINUE295 END IF296 END IF297 RETURN298 END IF299 *300 * Start the operations.301 *302 IF (lsame(trans,'N')) THEN303 *304 * Form C := alpha*A*B**T + alpha*B*A**T + C.305 *306 IF (upper) THEN307 DO 130 j = 1,n308 IF (beta.EQ.zero) THEN309 DO 90 i = 1,j310 c(i,j) = zero311 90 CONTINUE312 ELSE IF (beta.NE.one) THEN313 DO 100 i = 1,j314 c(i,j) = beta*c(i,j)315 100 CONTINUE316 END IF317 DO 120 l = 1,k318 IF ((a(j,l).NE.zero) .OR. (b(j,l).NE.zero)) THEN319 temp1 = alpha*b(j,l)320 temp2 = alpha*a(j,l)321 DO 110 i = 1,j322 c(i,j) = c(i,j) + a(i,l)*temp1 +323 + b(i,l)*temp2324 110 CONTINUE325 END IF326 120 CONTINUE327 130 CONTINUE328 ELSE329 DO 180 j = 1,n330 IF (beta.EQ.zero) THEN331 DO 140 i = j,n332 c(i,j) = zero333 140 CONTINUE334 ELSE IF (beta.NE.one) THEN335 DO 150 i = j,n336 c(i,j) = beta*c(i,j)337 150 CONTINUE338 END IF339 DO 170 l = 1,k340 IF ((a(j,l).NE.zero) .OR. (b(j,l).NE.zero)) THEN341 temp1 = alpha*b(j,l)342 temp2 = alpha*a(j,l)343 DO 160 i = j,n344 c(i,j) = c(i,j) + a(i,l)*temp1 +345 + b(i,l)*temp2346 160 CONTINUE347 END IF348 170 CONTINUE349 180 CONTINUE350 END IF351 ELSE352 *353 * Form C := alpha*A**T*B + alpha*B**T*A + C.354 *355 IF (upper) THEN356 DO 210 j = 1,n357 DO 200 i = 1,j358 temp1 = zero359 temp2 = zero360 DO 190 l = 1,k361 temp1 = temp1 + a(l,i)*b(l,j)362 temp2 = temp2 + b(l,i)*a(l,j)363 190 CONTINUE364 IF (beta.EQ.zero) THEN365 c(i,j) = alpha*temp1 + alpha*temp2366 ELSE367 c(i,j) = beta*c(i,j) + alpha*temp1 +368 + alpha*temp2369 END IF370 200 CONTINUE371 210 CONTINUE372 ELSE373 DO 240 j = 1,n374 DO 230 i = j,n375 temp1 = zero376 temp2 = zero377 DO 220 l = 1,k378 temp1 = temp1 + a(l,i)*b(l,j)379 temp2 = temp2 + b(l,i)*a(l,j)380 220 CONTINUE381 IF (beta.EQ.zero) THEN382 c(i,j) = alpha*temp1 + alpha*temp2383 ELSE384 c(i,j) = beta*c(i,j) + alpha*temp1 +385 + alpha*temp2386 END IF387 230 CONTINUE388 240 CONTINUE389 END IF390 END IF391 *392 RETURN393 *394 * End of CSYR2K.395 * AuthorGenerated automatically by Doxygen for LAPACK from the source code.
Index- NAME
- SYNOPSIS
- Functions/Subroutines
- Function/Subroutine Documentation
- subroutine CSYR2K (character UPLO, character TRANS, integer N, integer K, complex ALPHA, complex, dimension(lda,*) A, integer LDA, complex, dimension(ldb,*) B, integer LDB, complex BETA, complex, dimension(ldc,*) C, integer LDC)
- Author
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