SUBROUTINE ZSYR2K( UPLO, TRANS, N, K, ALPHA, A, LDA, B, LDB, $ BETA, C, LDC ) * * -- Automatically Tuned Linear Algebra Software (ATLAS) * (C) Copyright 2000 All Rights Reserved * * -- ATLAS routine -- F77 Interface -- Version 3.2 -- December 25, 2000 * * -- Suggestions, comments, bugs reports should be sent to the follo- * wing e-mail address: atlas@cs.utk.edu * * Author : Antoine P. Petitet * University of Tennessee - Innovative Computing Laboratory * Knoxville TN, 37996-1301, USA. * * --------------------------------------------------------------------- * * -- Copyright notice and Licensing terms: * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions, and the following disclaimer in * the documentation and/or other materials provided with the distri- * bution. * 3. The name of the University, the ATLAS group, or the names of its * contributors may not be used to endorse or promote products deri- * ved from this software without specific written permission. * * -- Disclaimer: * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEO- * RY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (IN- * CLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * --------------------------------------------------------------------- * * .. Scalar Arguments .. CHARACTER*1 UPLO, TRANS INTEGER N, K, LDA, LDB, LDC COMPLEX*16 ALPHA, BETA * .. * .. Array Arguments .. COMPLEX*16 A( LDA, * ), B( LDB, * ), C( LDC, * ) * .. * * Purpose * ======= * * ZSYR2K performs one of the symmetric rank 2k operations * * C := alpha * A * B' + alpha * B * A' + beta * C, * * or * * C := alpha * A' * B + alpha * B' * 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. * * Arguments * ========= * * UPLO (input) CHARACTER*1 * On entry, UPLO specifies whether the upper or lower triangu- * lar 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 (input) CHARACTER*1 * On entry, TRANS specifies the operation to be performed as * follows: * * TRANS = 'N' or 'n' C := alpha*A*B' + alpha*B*A' + beta*C, * * TRANS = 'T' or 't' C := alpha*B'*A + alpha*A'*B + beta*C. * * Unchanged on exit. * * N (input) INTEGER * On entry, N specifies the order of the matrix C. N must be at * least zero. Unchanged on exit. * * K (input) INTEGER * On entry, with TRANS = 'N' or 'n', K specifies the number of * columns of the matrices A and B, and with TRANS = 'T' or 't', * K specifies the number of rows of the matrices A and B. * K must be at least zero. Unchanged on exit. * * ALPHA (input) COMPLEX*16 * On entry, ALPHA specifies the scalar alpha. When ALPHA is * supplied as zero then the entries of the matrices A and B * need not be set on input. Unchanged on exit. * * A (input) COMPLEX*16 array * On entry, A is an 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. Unchanged on * exit. * * LDA (input) 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. * * B (input) COMPLEX*16 array * On entry, B is an 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. Unchanged on * exit. * * LDB (input) 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 ). Unchanged on exit. * * BETA (input) COMPLEX*16 * On entry, BETA specifies the scalar beta. When BETA is * supplied as zero then the entries of the matrix C need not * be set on input. Unchanged on exit. * * C (input/output) COMPLEX*16 array * On entry, C is an 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 con- * tain 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 (input) 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. * * Further Details * =============== * * For further information on the Level 1 BLAS specification, see: * * ``A Proposal for Standard Linear Algebra Subprograms'' by R. Hanson, * F. Krogh and C. Lawson, ACM SIGNUM Newsl., 8(16), 1973, * * ``Basic Linear Algebra Subprograms for Fortran Usage'' by C. Lawson, * R. Hanson, D. Kincaid and F. Krogh, ACM Transactions on Mathematical * Software, 5(3) pp 308-323, 1979. * * For further information on the Level 2 BLAS specification, see: * * ``An Extended Set of FORTRAN Basic Linear Algebra Subprograms'' by * J. Dongarra, J. Du Croz, S. Hammarling and R. Hanson, ACM Transac- * tions on Mathematical Software, 14(1) pp 1-17, 1988. * * ``Algorithm 656: An extended Set of Basic Linear Algebra Subprograms: * Model Implementation and Test Programs'' by J. Dongarra, J. Du Croz, * S. Hammarling and R. Hanson, ACM Transactions on Mathematical Soft- * ware, 14(1) pp 18-32, 1988. * * For further information on the Level 3 BLAS specification, see: * * ``A Set of Level 3 Basic Linear Algebra Subprograms'' by J. Dongarra, * J. Du Croz, I. Duff and S. Hammarling, ACM Transactions on Mathemati- * cal Software, 16(1), pp 1-17, 1990. * * ===================================================================== * * .. Parameters .. INTEGER ILOWER, IUPPER PARAMETER ( IUPPER = 121, ILOWER = 122 ) INTEGER ICOTRAN, INOTRAN, ITRAN PARAMETER ( INOTRAN = 111, ITRAN = 112, ICOTRAN = 113 ) * .. * .. Local Scalars .. INTEGER INFO, ITRANS, IUPLO, NROWA * .. * .. External Subroutines .. EXTERNAL ATL_F77WRAP_ZSYR2K, XERBLA * .. * .. External Functions .. EXTERNAL LSAME LOGICAL LSAME * .. * .. Intrinsic Functions .. INTRINSIC MAX * .. * .. Executable Statements .. * INFO = 0 * IF( LSAME( UPLO , 'L' ) ) THEN IUPLO = ILOWER ELSE IF( LSAME( UPLO , 'U' ) ) THEN IUPLO = IUPPER ELSE IUPLO = ILOWER INFO = 1 END IF * IF( LSAME( TRANS, 'N' ) ) THEN ITRANS = INOTRAN NROWA = N ELSE IF( LSAME( TRANS, 'T' ) ) THEN ITRANS = ITRAN NROWA = K ELSE IF( INFO.EQ.0 ) THEN ITRANS = INOTRAN NROWA = 0 INFO = 2 END IF * IF( INFO.EQ.0 ) THEN IF( N .LT.0 ) THEN INFO = 3 ELSE IF( K .LT.0 ) THEN INFO = 4 ELSE IF( LDA.LT.MAX( 1, NROWA ) ) THEN INFO = 7 ELSE IF( LDB.LT.MAX( 1, NROWA ) ) THEN INFO = 9 ELSE IF( LDC.LT.MAX( 1, N ) ) THEN INFO = 12 END IF END IF * IF( INFO.NE.0 ) THEN CALL XERBLA( 'ZSYR2K', INFO ) RETURN END IF * CALL ATL_F77WRAP_ZSYR2K( IUPLO, ITRANS, N, K, ALPHA, A, LDA, $ B, LDB, BETA, C, LDC ) * RETURN * * End of ZSYR2K * END