1
SUBROUTINE DSYR2( UPLO, N, ALPHA, X, INCX, Y, INCY, A, LDA )
3
* -- Automatically Tuned Linear Algebra Software (ATLAS)
4
* (C) Copyright 2000 All Rights Reserved
6
* -- ATLAS routine -- F77 Interface -- Version 3.2 -- December 15, 2000
8
* -- Suggestions, comments, bugs reports should be sent to the follo-
9
* wing e-mail address: atlas@cs.utk.edu
11
* Author : Antoine P. Petitet
12
* University of Tennessee - Innovative Computing Laboratory
13
* Knoxville TN, 37996-1301, USA.
15
* ---------------------------------------------------------------------
17
* -- Copyright notice and Licensing terms:
19
* Redistribution and use in source and binary forms, with or without
20
* modification, are permitted provided that the following conditions
23
* 1. Redistributions of source code must retain the above copyright
24
* notice, this list of conditions and the following disclaimer.
25
* 2. Redistributions in binary form must reproduce the above copyright
26
* notice, this list of conditions, and the following disclaimer in
27
* the documentation and/or other materials provided with the distri-
29
* 3. The name of the University, the ATLAS group, or the names of its
30
* contributors may not be used to endorse or promote products deri-
31
* ved from this software without specific written permission.
35
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
36
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
37
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
38
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY
39
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
40
* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
41
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
42
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEO-
43
* RY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (IN-
44
* CLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
45
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
47
* ---------------------------------------------------------------------
49
* .. Scalar Arguments ..
51
INTEGER INCX, INCY, LDA, N
52
DOUBLE PRECISION ALPHA
54
* .. Array Arguments ..
55
DOUBLE PRECISION A( LDA, * ), X( * ), Y( * )
61
* DSYR2 performs the symmetric rank 2 operation
63
* A := alpha*x*y' + alpha*y*x' + A,
65
* where alpha is a scalar, x and y are n-element vectors and A is an n
66
* by n symmetric matrix.
71
* UPLO (input) CHARACTER*1
72
* On entry, UPLO specifies whether the upper or lower triangu-
73
* lar part of the array A is to be referenced as follows:
75
* UPLO = 'U' or 'u' Only the upper triangular part of A
76
* is to be referenced.
78
* UPLO = 'L' or 'l' Only the lower triangular part of A
79
* is to be referenced.
84
* On entry, N specifies the order of the matrix A. N must be at
85
* least zero. Unchanged on exit.
87
* ALPHA (input) DOUBLE PRECISION
88
* On entry, ALPHA specifies the scalar alpha. When ALPHA is
89
* supplied as zero then the arrays X and Y need not be set on
90
* input. Unchanged on exit.
92
* X (input) DOUBLE PRECISION array
93
* On entry, X is an incremented array of dimension at least
94
* ( 1 + ( n - 1 ) * abs( INCX ) ). Before entry, the incremen-
95
* ted array X must contain the vector x. Unchanged on exit.
97
* INCX (input) INTEGER
98
* On entry, INCX specifies the increment for the elements of X.
99
* INCX must not be zero. Unchanged on exit.
101
* Y (input) DOUBLE PRECISION array
102
* On entry, Y is an incremented array of dimension at least
103
* ( 1 + ( n - 1 ) * abs( INCY ) ). Before entry, the incremen-
104
* ted array Y must contain the vector y. Unchanged on exit.
106
* INCY (input) INTEGER
107
* On entry, INCY specifies the increment for the elements of Y.
108
* INCY must not be zero. Unchanged on exit.
110
* A (input/output) DOUBLE PRECISION array
111
* On entry, A is an array of DIMENSION ( LDA, n ). Before en-
112
* try with UPLO = 'U' or 'u', the leading n by n upper trian-
113
* gular part of the array A must contain the upper triangular
114
* part of the symmetric matrix and the strictly lower triangu-
115
* lar part of A is not referenced. On exit, the upper triangu-
116
* lar part of the array A is overwritten by the upper triangu-
117
* lar part of the updated matrix. Before entry with UPLO = 'L'
118
* or 'l', the leading n by n lower triangular part of the array
119
* A must contain the lower triangular part of the symmetric
120
* matrix and the strictly upper triangular part of A is not
123
* LDA (input) INTEGER
124
* On entry, LDA specifies the first dimension of A as declared
125
* in the calling (sub) program. LDA must be at least max(1,n).
131
* For further information on the Level 1 BLAS specification, see:
133
* ``A Proposal for Standard Linear Algebra Subprograms'' by R. Hanson,
134
* F. Krogh and C. Lawson, ACM SIGNUM Newsl., 8(16), 1973,
136
* ``Basic Linear Algebra Subprograms for Fortran Usage'' by C. Lawson,
137
* R. Hanson, D. Kincaid and F. Krogh, ACM Transactions on Mathematical
138
* Software, 5(3) pp 308-323, 1979.
140
* For further information on the Level 2 BLAS specification, see:
142
* ``An Extended Set of FORTRAN Basic Linear Algebra Subprograms'' by
143
* J. Dongarra, J. Du Croz, S. Hammarling and R. Hanson, ACM Transac-
144
* tions on Mathematical Software, 14(1) pp 1-17, 1988.
146
* ``Algorithm 656: An extended Set of Basic Linear Algebra Subprograms:
147
* Model Implementation and Test Programs'' by J. Dongarra, J. Du Croz,
148
* S. Hammarling and R. Hanson, ACM Transactions on Mathematical Soft-
149
* ware, 14(1) pp 18-32, 1988.
151
* For further information on the Level 3 BLAS specification, see:
153
* ``A Set of Level 3 Basic Linear Algebra Subprograms'' by J. Dongarra,
154
* J. Du Croz, I. Duff and S. Hammarling, ACM Transactions on Mathemati-
155
* cal Software, 16(1), pp 1-17, 1990.
157
* =====================================================================
160
INTEGER ILOWER, IUPPER
161
PARAMETER ( IUPPER = 121, ILOWER = 122 )
163
* .. Local Scalars ..
166
* .. External Subroutines ..
167
EXTERNAL ATL_F77WRAP_DSYR2, XERBLA
169
* .. External Functions ..
173
* .. Intrinsic Functions ..
176
* .. Executable Statements ..
180
IF( LSAME( UPLO , 'U' ) ) THEN
182
ELSE IF( LSAME( UPLO , 'L' ) ) THEN
184
ELSE IF( INFO.EQ.0 ) THEN
191
ELSE IF( INCX.EQ.0 ) THEN
193
ELSE IF( INCY.EQ.0 ) THEN
195
ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
201
CALL XERBLA( 'DSYR2 ', INFO )
205
CALL ATL_F77WRAP_DSYR2( IUPLO, N, ALPHA, X, INCX, Y, INCY, A,
added
removed
interfaces/blas/F77/src/dsyr2.f
