127 SUBROUTINE ssytrs2( UPLO, N, NRHS, A, LDA, IPIV, B, LDB,
137 INTEGER info, lda, ldb, n, nrhs
141 REAL a( lda, * ),
b( ldb, * ), work( * )
148 parameter( one = 1.0e+0 )
152 INTEGER i, iinfo,
j, k, kp
153 REAL ak, akm1, akm1k, bk, bkm1, denom
168 upper =
lsame( uplo,
'U' )
169 IF( .NOT.upper .AND. .NOT.
lsame( uplo,
'L' ) )
THEN
171 ELSE IF( n.LT.0 )
THEN
173 ELSE IF( nrhs.LT.0 )
THEN
175 ELSE IF( lda.LT.max( 1, n ) )
THEN
177 ELSE IF( ldb.LT.max( 1, n ) )
THEN
181 CALL
xerbla(
'SSYTRS2', -info )
187 IF( n.EQ.0 .OR. nrhs.EQ.0 )
192 CALL
ssyconv( uplo,
'C', n, a, lda, ipiv, work, iinfo )
200 DO WHILE ( k .GE. 1 )
201 IF( ipiv( k ).GT.0 )
THEN
206 $ CALL
sswap( nrhs,
b( k, 1 ), ldb,
b( kp, 1 ), ldb )
212 IF( kp.EQ.-ipiv( k-1 ) )
213 $ CALL
sswap( nrhs,
b( k-1, 1 ), ldb,
b( kp, 1 ), ldb )
220 CALL
strsm(
'L',
'U',
'N',
'U',n,nrhs,one,a,lda,
b,ldb)
225 DO WHILE ( i .GE. 1 )
226 IF( ipiv(i) .GT. 0 )
THEN
227 CALL
sscal( nrhs, one / a( i, i ),
b( i, 1 ), ldb )
228 ELSEIF ( i .GT. 1)
THEN
229 IF ( ipiv(i-1) .EQ. ipiv(i) )
THEN
231 akm1 = a( i-1, i-1 ) / akm1k
232 ak = a( i, i ) / akm1k
233 denom = akm1*ak - one
235 bkm1 =
b( i-1,
j ) / akm1k
236 bk =
b( i,
j ) / akm1k
237 b( i-1,
j ) = ( ak*bkm1-bk ) / denom
238 b( i,
j ) = ( akm1*bk-bkm1 ) / denom
248 CALL
strsm(
'L',
'U',
'T',
'U',n,nrhs,one,a,lda,
b,ldb)
253 DO WHILE ( k .LE. n )
254 IF( ipiv( k ).GT.0 )
THEN
259 $ CALL
sswap( nrhs,
b( k, 1 ), ldb,
b( kp, 1 ), ldb )
265 IF( k .LT. n .AND. kp.EQ.-ipiv( k+1 ) )
266 $ CALL
sswap( nrhs,
b( k, 1 ), ldb,
b( kp, 1 ), ldb )
277 DO WHILE ( k .LE. n )
278 IF( ipiv( k ).GT.0 )
THEN
283 $ CALL
sswap( nrhs,
b( k, 1 ), ldb,
b( kp, 1 ), ldb )
289 IF( kp.EQ.-ipiv( k ) )
290 $ CALL
sswap( nrhs,
b( k+1, 1 ), ldb,
b( kp, 1 ), ldb )
297 CALL
strsm(
'L',
'L',
'N',
'U',n,nrhs,one,a,lda,
b,ldb)
302 DO WHILE ( i .LE. n )
303 IF( ipiv(i) .GT. 0 )
THEN
304 CALL
sscal( nrhs, one / a( i, i ),
b( i, 1 ), ldb )
307 akm1 = a( i, i ) / akm1k
308 ak = a( i+1, i+1 ) / akm1k
309 denom = akm1*ak - one
311 bkm1 =
b( i,
j ) / akm1k
312 bk =
b( i+1,
j ) / akm1k
313 b( i,
j ) = ( ak*bkm1-bk ) / denom
314 b( i+1,
j ) = ( akm1*bk-bkm1 ) / denom
323 CALL
strsm(
'L',
'L',
'T',
'U',n,nrhs,one,a,lda,
b,ldb)
328 DO WHILE ( k .GE. 1 )
329 IF( ipiv( k ).GT.0 )
THEN
334 $ CALL
sswap( nrhs,
b( k, 1 ), ldb,
b( kp, 1 ), ldb )
340 IF( k.GT.1 .AND. kp.EQ.-ipiv( k-1 ) )
341 $ CALL
sswap( nrhs,
b( k, 1 ), ldb,
b( kp, 1 ), ldb )
350 CALL
ssyconv( uplo,
'R', n, a, lda, ipiv, work, iinfo )
subroutine sswap(N, SX, INCX, SY, INCY)
SSWAP
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine ssyconv(UPLO, WAY, N, A, LDA, IPIV, WORK, INFO)
SSYCONV
set ue cd $ADTTMP cat<< EOF > tmp f Program LinearEquations Implicit none Real b(3) integer i
logical function lsame(CA, CB)
LSAME
set ue cd $ADTTMP cat<< EOF > tmp f Program LinearEquations Implicit none Real j
subroutine ssytrs2(UPLO, N, NRHS, A, LDA, IPIV, B, LDB, WORK, INFO)
SSYTRS2
subroutine strsm(SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA, B, LDB)
STRSM
subroutine sscal(N, SA, SX, INCX)
SSCAL