diff --git a/lapack-netlib/zgbsvx.f b/lapack-netlib/zgbsvx.f deleted file mode 100644 index 871564a81..000000000 --- a/lapack-netlib/zgbsvx.f +++ /dev/null @@ -1,644 +0,0 @@ -*> \brief ZGBSVX computes the solution to system of linear equations A * X = B for GB matrices -* -* =========== DOCUMENTATION =========== -* -* Online html documentation available at -* http://www.netlib.org/lapack/explore-html/ -* -*> \htmlonly -*> Download ZGBSVX + dependencies -*> -*> [TGZ] -*> -*> [ZIP] -*> -*> [TXT] -*> \endhtmlonly -* -* Definition: -* =========== -* -* SUBROUTINE ZGBSVX( FACT, TRANS, N, KL, KU, NRHS, AB, LDAB, AFB, -* LDAFB, IPIV, EQUED, R, C, B, LDB, X, LDX, -* RCOND, FERR, BERR, WORK, RWORK, INFO ) -* -* .. Scalar Arguments .. -* CHARACTER EQUED, FACT, TRANS -* INTEGER INFO, KL, KU, LDAB, LDAFB, LDB, LDX, N, NRHS -* DOUBLE PRECISION RCOND -* .. -* .. Array Arguments .. -* INTEGER IPIV( * ) -* DOUBLE PRECISION BERR( * ), C( * ), FERR( * ), R( * ), -* $ RWORK( * ) -* COMPLEX*16 AB( LDAB, * ), AFB( LDAFB, * ), B( LDB, * ), -* $ WORK( * ), X( LDX, * ) -* .. -* -* -*> \par Purpose: -* ============= -*> -*> \verbatim -*> -*> ZGBSVX uses the LU factorization to compute the solution to a complex -*> system of linear equations A * X = B, A**T * X = B, or A**H * X = B, -*> where A is a band matrix of order N with KL subdiagonals and KU -*> superdiagonals, and X and B are N-by-NRHS matrices. -*> -*> Error bounds on the solution and a condition estimate are also -*> provided. -*> \endverbatim -* -*> \par Description: -* ================= -*> -*> \verbatim -*> -*> The following steps are performed by this subroutine: -*> -*> 1. If FACT = 'E', real scaling factors are computed to equilibrate -*> the system: -*> TRANS = 'N': diag(R)*A*diag(C) *inv(diag(C))*X = diag(R)*B -*> TRANS = 'T': (diag(R)*A*diag(C))**T *inv(diag(R))*X = diag(C)*B -*> TRANS = 'C': (diag(R)*A*diag(C))**H *inv(diag(R))*X = diag(C)*B -*> Whether or not the system will be equilibrated depends on the -*> scaling of the matrix A, but if equilibration is used, A is -*> overwritten by diag(R)*A*diag(C) and B by diag(R)*B (if TRANS='N') -*> or diag(C)*B (if TRANS = 'T' or 'C'). -*> -*> 2. If FACT = 'N' or 'E', the LU decomposition is used to factor the -*> matrix A (after equilibration if FACT = 'E') as -*> A = L * U, -*> where L is a product of permutation and unit lower triangular -*> matrices with KL subdiagonals, and U is upper triangular with -*> KL+KU superdiagonals. -*> -*> 3. If some U(i,i)=0, so that U is exactly singular, then the routine -*> returns with INFO = i. Otherwise, the factored form of A is used -*> to estimate the condition number of the matrix A. If the -*> reciprocal of the condition number is less than machine precision, -*> INFO = N+1 is returned as a warning, but the routine still goes on -*> to solve for X and compute error bounds as described below. -*> -*> 4. The system of equations is solved for X using the factored form -*> of A. -*> -*> 5. Iterative refinement is applied to improve the computed solution -*> matrix and calculate error bounds and backward error estimates -*> for it. -*> -*> 6. If equilibration was used, the matrix X is premultiplied by -*> diag(C) (if TRANS = 'N') or diag(R) (if TRANS = 'T' or 'C') so -*> that it solves the original system before equilibration. -*> \endverbatim -* -* Arguments: -* ========== -* -*> \param[in] FACT -*> \verbatim -*> FACT is CHARACTER*1 -*> Specifies whether or not the factored form of the matrix A is -*> supplied on entry, and if not, whether the matrix A should be -*> equilibrated before it is factored. -*> = 'F': On entry, AFB and IPIV contain the factored form of -*> A. If EQUED is not 'N', the matrix A has been -*> equilibrated with scaling factors given by R and C. -*> AB, AFB, and IPIV are not modified. -*> = 'N': The matrix A will be copied to AFB and factored. -*> = 'E': The matrix A will be equilibrated if necessary, then -*> copied to AFB and factored. -*> \endverbatim -*> -*> \param[in] TRANS -*> \verbatim -*> TRANS is CHARACTER*1 -*> Specifies the form of the system of equations. -*> = 'N': A * X = B (No transpose) -*> = 'T': A**T * X = B (Transpose) -*> = 'C': A**H * X = B (Conjugate transpose) -*> \endverbatim -*> -*> \param[in] N -*> \verbatim -*> N is INTEGER -*> The number of linear equations, i.e., the order of the -*> matrix A. N >= 0. -*> \endverbatim -*> -*> \param[in] KL -*> \verbatim -*> KL is INTEGER -*> The number of subdiagonals within the band of A. KL >= 0. -*> \endverbatim -*> -*> \param[in] KU -*> \verbatim -*> KU is INTEGER -*> The number of superdiagonals within the band of A. KU >= 0. -*> \endverbatim -*> -*> \param[in] NRHS -*> \verbatim -*> NRHS is INTEGER -*> The number of right hand sides, i.e., the number of columns -*> of the matrices B and X. NRHS >= 0. -*> \endverbatim -*> -*> \param[in,out] AB -*> \verbatim -*> AB is COMPLEX*16 array, dimension (LDAB,N) -*> On entry, the matrix A in band storage, in rows 1 to KL+KU+1. -*> The j-th column of A is stored in the j-th column of the -*> array AB as follows: -*> AB(KU+1+i-j,j) = A(i,j) for max(1,j-KU)<=i<=min(N,j+kl) -*> -*> If FACT = 'F' and EQUED is not 'N', then A must have been -*> equilibrated by the scaling factors in R and/or C. AB is not -*> modified if FACT = 'F' or 'N', or if FACT = 'E' and -*> EQUED = 'N' on exit. -*> -*> On exit, if EQUED .ne. 'N', A is scaled as follows: -*> EQUED = 'R': A := diag(R) * A -*> EQUED = 'C': A := A * diag(C) -*> EQUED = 'B': A := diag(R) * A * diag(C). -*> \endverbatim -*> -*> \param[in] LDAB -*> \verbatim -*> LDAB is INTEGER -*> The leading dimension of the array AB. LDAB >= KL+KU+1. -*> \endverbatim -*> -*> \param[in,out] AFB -*> \verbatim -*> AFB is COMPLEX*16 array, dimension (LDAFB,N) -*> If FACT = 'F', then AFB is an input argument and on entry -*> contains details of the LU factorization of the band matrix -*> A, as computed by ZGBTRF. U is stored as an upper triangular -*> band matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, -*> and the multipliers used during the factorization are stored -*> in rows KL+KU+2 to 2*KL+KU+1. If EQUED .ne. 'N', then AFB is -*> the factored form of the equilibrated matrix A. -*> -*> If FACT = 'N', then AFB is an output argument and on exit -*> returns details of the LU factorization of A. -*> -*> If FACT = 'E', then AFB is an output argument and on exit -*> returns details of the LU factorization of the equilibrated -*> matrix A (see the description of AB for the form of the -*> equilibrated matrix). -*> \endverbatim -*> -*> \param[in] LDAFB -*> \verbatim -*> LDAFB is INTEGER -*> The leading dimension of the array AFB. LDAFB >= 2*KL+KU+1. -*> \endverbatim -*> -*> \param[in,out] IPIV -*> \verbatim -*> IPIV is INTEGER array, dimension (N) -*> If FACT = 'F', then IPIV is an input argument and on entry -*> contains the pivot indices from the factorization A = L*U -*> as computed by ZGBTRF; row i of the matrix was interchanged -*> with row IPIV(i). -*> -*> If FACT = 'N', then IPIV is an output argument and on exit -*> contains the pivot indices from the factorization A = L*U -*> of the original matrix A. -*> -*> If FACT = 'E', then IPIV is an output argument and on exit -*> contains the pivot indices from the factorization A = L*U -*> of the equilibrated matrix A. -*> \endverbatim -*> -*> \param[in,out] EQUED -*> \verbatim -*> EQUED is CHARACTER*1 -*> Specifies the form of equilibration that was done. -*> = 'N': No equilibration (always true if FACT = 'N'). -*> = 'R': Row equilibration, i.e., A has been premultiplied by -*> diag(R). -*> = 'C': Column equilibration, i.e., A has been postmultiplied -*> by diag(C). -*> = 'B': Both row and column equilibration, i.e., A has been -*> replaced by diag(R) * A * diag(C). -*> EQUED is an input argument if FACT = 'F'; otherwise, it is an -*> output argument. -*> \endverbatim -*> -*> \param[in,out] R -*> \verbatim -*> R is DOUBLE PRECISION array, dimension (N) -*> The row scale factors for A. If EQUED = 'R' or 'B', A is -*> multiplied on the left by diag(R); if EQUED = 'N' or 'C', R -*> is not accessed. R is an input argument if FACT = 'F'; -*> otherwise, R is an output argument. If FACT = 'F' and -*> EQUED = 'R' or 'B', each element of R must be positive. -*> \endverbatim -*> -*> \param[in,out] C -*> \verbatim -*> C is DOUBLE PRECISION array, dimension (N) -*> The column scale factors for A. If EQUED = 'C' or 'B', A is -*> multiplied on the right by diag(C); if EQUED = 'N' or 'R', C -*> is not accessed. C is an input argument if FACT = 'F'; -*> otherwise, C is an output argument. If FACT = 'F' and -*> EQUED = 'C' or 'B', each element of C must be positive. -*> \endverbatim -*> -*> \param[in,out] B -*> \verbatim -*> B is COMPLEX*16 array, dimension (LDB,NRHS) -*> On entry, the right hand side matrix B. -*> On exit, -*> if EQUED = 'N', B is not modified; -*> if TRANS = 'N' and EQUED = 'R' or 'B', B is overwritten by -*> diag(R)*B; -*> if TRANS = 'T' or 'C' and EQUED = 'C' or 'B', B is -*> overwritten by diag(C)*B. -*> \endverbatim -*> -*> \param[in] LDB -*> \verbatim -*> LDB is INTEGER -*> The leading dimension of the array B. LDB >= max(1,N). -*> \endverbatim -*> -*> \param[out] X -*> \verbatim -*> X is COMPLEX*16 array, dimension (LDX,NRHS) -*> If INFO = 0 or INFO = N+1, the N-by-NRHS solution matrix X -*> to the original system of equations. Note that A and B are -*> modified on exit if EQUED .ne. 'N', and the solution to the -*> equilibrated system is inv(diag(C))*X if TRANS = 'N' and -*> EQUED = 'C' or 'B', or inv(diag(R))*X if TRANS = 'T' or 'C' -*> and EQUED = 'R' or 'B'. -*> \endverbatim -*> -*> \param[in] LDX -*> \verbatim -*> LDX is INTEGER -*> The leading dimension of the array X. LDX >= max(1,N). -*> \endverbatim -*> -*> \param[out] RCOND -*> \verbatim -*> RCOND is DOUBLE PRECISION -*> The estimate of the reciprocal condition number of the matrix -*> A after equilibration (if done). If RCOND is less than the -*> machine precision (in particular, if RCOND = 0), the matrix -*> is singular to working precision. This condition is -*> indicated by a return code of INFO > 0. -*> \endverbatim -*> -*> \param[out] FERR -*> \verbatim -*> FERR is DOUBLE PRECISION array, dimension (NRHS) -*> The estimated forward error bound for each solution vector -*> X(j) (the j-th column of the solution matrix X). -*> If XTRUE is the true solution corresponding to X(j), FERR(j) -*> is an estimated upper bound for the magnitude of the largest -*> element in (X(j) - XTRUE) divided by the magnitude of the -*> largest element in X(j). The estimate is as reliable as -*> the estimate for RCOND, and is almost always a slight -*> overestimate of the true error. -*> \endverbatim -*> -*> \param[out] BERR -*> \verbatim -*> BERR is DOUBLE PRECISION array, dimension (NRHS) -*> The componentwise relative backward error of each solution -*> vector X(j) (i.e., the smallest relative change in -*> any element of A or B that makes X(j) an exact solution). -*> \endverbatim -*> -*> \param[out] WORK -*> \verbatim -*> WORK is COMPLEX*16 array, dimension (2*N) -*> \endverbatim -*> -*> \param[out] RWORK -*> \verbatim -*> RWORK is DOUBLE PRECISION array, dimension (MAX(1,N)) -*> On exit, RWORK(1) contains the reciprocal pivot growth -*> factor norm(A)/norm(U). The "max absolute element" norm is -*> used. If RWORK(1) is much less than 1, then the stability -*> of the LU factorization of the (equilibrated) matrix A -*> could be poor. This also means that the solution X, condition -*> estimator RCOND, and forward error bound FERR could be -*> unreliable. If factorization fails with 0 RWORK(1) contains the reciprocal pivot growth factor for the -*> leading INFO columns of A. -*> \endverbatim -*> -*> \param[out] INFO -*> \verbatim -*> INFO is INTEGER -*> = 0: successful exit -*> < 0: if INFO = -i, the i-th argument had an illegal value -*> > 0: if INFO = i, and i is -*> <= N: U(i,i) is exactly zero. The factorization -*> has been completed, but the factor U is exactly -*> singular, so the solution and error bounds -*> could not be computed. RCOND = 0 is returned. -*> = N+1: U is nonsingular, but RCOND is less than machine -*> precision, meaning that the matrix is singular -*> to working precision. Nevertheless, the -*> solution and error bounds are computed because -*> there are a number of situations where the -*> computed solution can be more accurate than the -*> value of RCOND would suggest. -*> \endverbatim -* -* Authors: -* ======== -* -*> \author Univ. of Tennessee -*> \author Univ. of California Berkeley -*> \author Univ. of Colorado Denver -*> \author NAG Ltd. -* -*> \ingroup complex16GBsolve -* -* ===================================================================== - SUBROUTINE ZGBSVX( FACT, TRANS, N, KL, KU, NRHS, AB, LDAB, AFB, - $ LDAFB, IPIV, EQUED, R, C, B, LDB, X, LDX, - $ RCOND, FERR, BERR, WORK, RWORK, INFO ) -* -* -- LAPACK driver routine -- -* -- LAPACK is a software package provided by Univ. of Tennessee, -- -* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- -* -* .. Scalar Arguments .. - CHARACTER EQUED, FACT, TRANS - INTEGER INFO, KL, KU, LDAB, LDAFB, LDB, LDX, N, NRHS - DOUBLE PRECISION RCOND -* .. -* .. Array Arguments .. - INTEGER IPIV( * ) - DOUBLE PRECISION BERR( * ), C( * ), FERR( * ), R( * ), - $ RWORK( * ) - COMPLEX*16 AB( LDAB, * ), AFB( LDAFB, * ), B( LDB, * ), - $ WORK( * ), X( LDX, * ) -* .. -* -* ===================================================================== -* Moved setting of INFO = N+1 so INFO does not subsequently get -* overwritten. Sven, 17 Mar 05. -* ===================================================================== -* -* .. Parameters .. - DOUBLE PRECISION ZERO, ONE - PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 ) -* .. -* .. Local Scalars .. - LOGICAL COLEQU, EQUIL, NOFACT, NOTRAN, ROWEQU - CHARACTER NORM - INTEGER I, INFEQU, J, J1, J2 - DOUBLE PRECISION AMAX, ANORM, BIGNUM, COLCND, RCMAX, RCMIN, - $ ROWCND, RPVGRW, SMLNUM -* .. -* .. External Functions .. - LOGICAL LSAME - DOUBLE PRECISION DLAMCH, ZLANGB, ZLANTB - EXTERNAL LSAME, DLAMCH, ZLANGB, ZLANTB -* .. -* .. External Subroutines .. - EXTERNAL XERBLA, ZCOPY, ZGBCON, ZGBEQU, ZGBRFS, ZGBTRF, - $ ZGBTRS, ZLACPY, ZLAQGB -* .. -* .. Intrinsic Functions .. - INTRINSIC ABS, MAX, MIN -* .. -* .. Executable Statements .. -* - INFO = 0 - NOFACT = LSAME( FACT, 'N' ) - EQUIL = LSAME( FACT, 'E' ) - NOTRAN = LSAME( TRANS, 'N' ) - IF( NOFACT .OR. EQUIL ) THEN - EQUED = 'N' - ROWEQU = .FALSE. - COLEQU = .FALSE. - ELSE - ROWEQU = LSAME( EQUED, 'R' ) .OR. LSAME( EQUED, 'B' ) - COLEQU = LSAME( EQUED, 'C' ) .OR. LSAME( EQUED, 'B' ) - SMLNUM = DLAMCH( 'Safe minimum' ) - BIGNUM = ONE / SMLNUM - END IF -* -* Test the input parameters. -* - IF( .NOT.NOFACT .AND. .NOT.EQUIL .AND. .NOT.LSAME( FACT, 'F' ) ) - $ THEN - INFO = -1 - ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'T' ) .AND. .NOT. - $ LSAME( TRANS, 'C' ) ) THEN - INFO = -2 - ELSE IF( N.LT.0 ) THEN - INFO = -3 - ELSE IF( KL.LT.0 ) THEN - INFO = -4 - ELSE IF( KU.LT.0 ) THEN - INFO = -5 - ELSE IF( NRHS.LT.0 ) THEN - INFO = -6 - ELSE IF( LDAB.LT.KL+KU+1 ) THEN - INFO = -8 - ELSE IF( LDAFB.LT.2*KL+KU+1 ) THEN - INFO = -10 - ELSE IF( LSAME( FACT, 'F' ) .AND. .NOT. - $ ( ROWEQU .OR. COLEQU .OR. LSAME( EQUED, 'N' ) ) ) THEN - INFO = -12 - ELSE - IF( ROWEQU ) THEN - RCMIN = BIGNUM - RCMAX = ZERO - DO 10 J = 1, N - RCMIN = MIN( RCMIN, R( J ) ) - RCMAX = MAX( RCMAX, R( J ) ) - 10 CONTINUE - IF( RCMIN.LE.ZERO ) THEN - INFO = -13 - ELSE IF( N.GT.0 ) THEN - ROWCND = MAX( RCMIN, SMLNUM ) / MIN( RCMAX, BIGNUM ) - ELSE - ROWCND = ONE - END IF - END IF - IF( COLEQU .AND. INFO.EQ.0 ) THEN - RCMIN = BIGNUM - RCMAX = ZERO - DO 20 J = 1, N - RCMIN = MIN( RCMIN, C( J ) ) - RCMAX = MAX( RCMAX, C( J ) ) - 20 CONTINUE - IF( RCMIN.LE.ZERO ) THEN - INFO = -14 - ELSE IF( N.GT.0 ) THEN - COLCND = MAX( RCMIN, SMLNUM ) / MIN( RCMAX, BIGNUM ) - ELSE - COLCND = ONE - END IF - END IF - IF( INFO.EQ.0 ) THEN - IF( LDB.LT.MAX( 1, N ) ) THEN - INFO = -16 - ELSE IF( LDX.LT.MAX( 1, N ) ) THEN - INFO = -18 - END IF - END IF - END IF -* - IF( INFO.NE.0 ) THEN - CALL XERBLA( 'ZGBSVX', -INFO ) - RETURN - END IF -* - IF( EQUIL ) THEN -* -* Compute row and column scalings to equilibrate the matrix A. -* - CALL ZGBEQU( N, N, KL, KU, AB, LDAB, R, C, ROWCND, COLCND, - $ AMAX, INFEQU ) - IF( INFEQU.EQ.0 ) THEN -* -* Equilibrate the matrix. -* - CALL ZLAQGB( N, N, KL, KU, AB, LDAB, R, C, ROWCND, COLCND, - $ AMAX, EQUED ) - ROWEQU = LSAME( EQUED, 'R' ) .OR. LSAME( EQUED, 'B' ) - COLEQU = LSAME( EQUED, 'C' ) .OR. LSAME( EQUED, 'B' ) - END IF - END IF -* -* Scale the right hand side. -* - IF( NOTRAN ) THEN - IF( ROWEQU ) THEN - DO 40 J = 1, NRHS - DO 30 I = 1, N - B( I, J ) = R( I )*B( I, J ) - 30 CONTINUE - 40 CONTINUE - END IF - ELSE IF( COLEQU ) THEN - DO 60 J = 1, NRHS - DO 50 I = 1, N - B( I, J ) = C( I )*B( I, J ) - 50 CONTINUE - 60 CONTINUE - END IF -* - IF( NOFACT .OR. EQUIL ) THEN -* -* Compute the LU factorization of the band matrix A. -* - DO 70 J = 1, N - J1 = MAX( J-KU, 1 ) - J2 = MIN( J+KL, N ) - CALL ZCOPY( J2-J1+1, AB( KU+1-J+J1, J ), 1, - $ AFB( KL+KU+1-J+J1, J ), 1 ) - 70 CONTINUE -* - CALL ZGBTRF( N, N, KL, KU, AFB, LDAFB, IPIV, INFO ) -* -* Return if INFO is non-zero. -* - IF( INFO.GT.0 ) THEN -* -* Compute the reciprocal pivot growth factor of the -* leading rank-deficient INFO columns of A. -* - ANORM = ZERO - DO 90 J = 1, INFO - DO 80 I = MAX( KU+2-J, 1 ), MIN( N+KU+1-J, KL+KU+1 ) - ANORM = MAX( ANORM, ABS( AB( I, J ) ) ) - 80 CONTINUE - 90 CONTINUE - RPVGRW = ZLANTB( 'M', 'U', 'N', INFO, MIN( INFO-1, KL+KU ), - $ AFB( MAX( 1, KL+KU+2-INFO ), 1 ), LDAFB, - $ RWORK ) - IF( RPVGRW.EQ.ZERO ) THEN - RPVGRW = ONE - ELSE - RPVGRW = ANORM / RPVGRW - END IF - RWORK( 1 ) = RPVGRW - RCOND = ZERO - RETURN - END IF - END IF -* -* Compute the norm of the matrix A and the -* reciprocal pivot growth factor RPVGRW. -* - IF( NOTRAN ) THEN - NORM = '1' - ELSE - NORM = 'I' - END IF - ANORM = ZLANGB( NORM, N, KL, KU, AB, LDAB, RWORK ) - RPVGRW = ZLANTB( 'M', 'U', 'N', N, KL+KU, AFB, LDAFB, RWORK ) - IF( RPVGRW.EQ.ZERO ) THEN - RPVGRW = ONE - ELSE - RPVGRW = ZLANGB( 'M', N, KL, KU, AB, LDAB, RWORK ) / RPVGRW - END IF -* -* Compute the reciprocal of the condition number of A. -* - CALL ZGBCON( NORM, N, KL, KU, AFB, LDAFB, IPIV, ANORM, RCOND, - $ WORK, RWORK, INFO ) -* -* Compute the solution matrix X. -* - CALL ZLACPY( 'Full', N, NRHS, B, LDB, X, LDX ) - CALL ZGBTRS( TRANS, N, KL, KU, NRHS, AFB, LDAFB, IPIV, X, LDX, - $ INFO ) -* -* Use iterative refinement to improve the computed solution and -* compute error bounds and backward error estimates for it. -* - CALL ZGBRFS( TRANS, N, KL, KU, NRHS, AB, LDAB, AFB, LDAFB, IPIV, - $ B, LDB, X, LDX, FERR, BERR, WORK, RWORK, INFO ) -* -* Transform the solution matrix X to a solution of the original -* system. -* - IF( NOTRAN ) THEN - IF( COLEQU ) THEN - DO 110 J = 1, NRHS - DO 100 I = 1, N - X( I, J ) = C( I )*X( I, J ) - 100 CONTINUE - 110 CONTINUE - DO 120 J = 1, NRHS - FERR( J ) = FERR( J ) / COLCND - 120 CONTINUE - END IF - ELSE IF( ROWEQU ) THEN - DO 140 J = 1, NRHS - DO 130 I = 1, N - X( I, J ) = R( I )*X( I, J ) - 130 CONTINUE - 140 CONTINUE - DO 150 J = 1, NRHS - FERR( J ) = FERR( J ) / ROWCND - 150 CONTINUE - END IF -* -* Set INFO = N+1 if the matrix is singular to working precision. -* - IF( RCOND.LT.DLAMCH( 'Epsilon' ) ) - $ INFO = N + 1 -* - RWORK( 1 ) = RPVGRW - RETURN -* -* End of ZGBSVX -* - END