121 SUBROUTINE cpocon( UPLO, N, A, LDA, ANORM, RCOND, WORK, RWORK,
136 COMPLEX A( lda, * ), WORK( * )
143 parameter ( one = 1.0e+0, zero = 0.0e+0 )
149 REAL AINVNM, SCALE, SCALEL, SCALEU, SMLNUM
159 EXTERNAL lsame, icamax, slamch
165 INTRINSIC abs, aimag, max, real
171 cabs1( zdum ) = abs(
REAL( ZDUM ) ) + abs( AIMAG( zdum ) )
178 upper = lsame( uplo,
'U' )
179 IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
181 ELSE IF( n.LT.0 )
THEN
183 ELSE IF( lda.LT.max( 1, n ) )
THEN
185 ELSE IF( anorm.LT.zero )
THEN
189 CALL xerbla(
'CPOCON', -info )
199 ELSE IF( anorm.EQ.zero )
THEN
203 smlnum = slamch(
'Safe minimum' )
210 CALL clacn2( n, work( n+1 ), work, ainvnm, kase, isave )
216 CALL clatrs(
'Upper',
'Conjugate transpose',
'Non-unit',
217 $ normin, n, a, lda, work, scalel, rwork, info )
222 CALL clatrs(
'Upper',
'No transpose',
'Non-unit', normin, n,
223 $ a, lda, work, scaleu, rwork, info )
228 CALL clatrs(
'Lower',
'No transpose',
'Non-unit', normin, n,
229 $ a, lda, work, scalel, rwork, info )
234 CALL clatrs(
'Lower',
'Conjugate transpose',
'Non-unit',
235 $ normin, n, a, lda, work, scaleu, rwork, info )
240 scale = scalel*scaleu
241 IF( scale.NE.one )
THEN
242 ix = icamax( n, work, 1 )
243 IF( scale.LT.cabs1( work( ix ) )*smlnum .OR. scale.EQ.zero )
245 CALL csrscl( n, scale, work, 1 )
253 $ rcond = ( one / ainvnm ) / anorm
subroutine csrscl(N, SA, SX, INCX)
CSRSCL multiplies a vector by the reciprocal of a real scalar.
subroutine cpocon(UPLO, N, A, LDA, ANORM, RCOND, WORK, RWORK, INFO)
CPOCON
subroutine clatrs(UPLO, TRANS, DIAG, NORMIN, N, A, LDA, X, SCALE, CNORM, INFO)
CLATRS solves a triangular system of equations with the scale factor set to prevent overflow...
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine clacn2(N, V, X, EST, KASE, ISAVE)
CLACN2 estimates the 1-norm of a square matrix, using reverse communication for evaluating matrix-vec...