/* zgbrfsx.f -- translated by f2c (version 20061008). You must link the resulting object file with libf2c: on Microsoft Windows system, link with libf2c.lib; on Linux or Unix systems, link with .../path/to/libf2c.a -lm or, if you install libf2c.a in a standard place, with -lf2c -lm -- in that order, at the end of the command line, as in cc *.o -lf2c -lm Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., http://www.netlib.org/f2c/libf2c.zip */ #include "f2c.h" #include "blaswrap.h" /* Table of constant values */ static logical c_true = TRUE_; static logical c_false = FALSE_; /* Subroutine */ int zgbrfsx_(char *trans, char *equed, integer *n, integer * kl, integer *ku, integer *nrhs, doublecomplex *ab, integer *ldab, doublecomplex *afb, integer *ldafb, integer *ipiv, doublereal *r__, doublereal *c__, doublecomplex *b, integer *ldb, doublecomplex *x, integer *ldx, doublereal *rcond, doublereal *berr, integer * n_err_bnds__, doublereal *err_bnds_norm__, doublereal * err_bnds_comp__, integer *nparams, doublereal *params, doublecomplex * work, doublereal *rwork, integer *info) { /* System generated locals */ integer ab_dim1, ab_offset, afb_dim1, afb_offset, b_dim1, b_offset, x_dim1, x_offset, err_bnds_norm_dim1, err_bnds_norm_offset, err_bnds_comp_dim1, err_bnds_comp_offset, i__1; doublereal d__1, d__2; /* Builtin functions */ double sqrt(doublereal); /* Local variables */ doublereal illrcond_thresh__, unstable_thresh__, err_lbnd__; integer ref_type__; extern integer ilatrans_(char *); integer j; doublereal rcond_tmp__; integer prec_type__, trans_type__; doublereal cwise_wrong__; extern /* Subroutine */ int zla_gbrfsx_extended__(integer *, integer *, integer *, integer *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer *, logical *, doublereal *, doublecomplex *, integer *, doublecomplex *, integer *, doublereal *, integer *, doublereal *, doublereal *, doublecomplex *, doublereal *, doublecomplex *, doublecomplex *, doublereal *, integer *, doublereal *, doublereal *, logical *, integer *); char norm[1]; logical ignore_cwise__; extern logical lsame_(char *, char *); doublereal anorm; extern doublereal zla_gbrcond_c__(char *, integer *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer * , doublereal *, logical *, integer *, doublecomplex *, doublereal *, ftnlen), zla_gbrcond_x__(char *, integer *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, doublereal *, ftnlen), dlamch_(char *); extern /* Subroutine */ int xerbla_(char *, integer *); extern doublereal zlangb_(char *, integer *, integer *, integer *, doublecomplex *, integer *, doublereal *); extern /* Subroutine */ int zgbcon_(char *, integer *, integer *, integer *, doublecomplex *, integer *, integer *, doublereal *, doublereal *, doublecomplex *, doublereal *, integer *); logical colequ, notran, rowequ; extern integer ilaprec_(char *); integer ithresh, n_norms__; doublereal rthresh; /* -- LAPACK routine (version 3.2.1) -- */ /* -- Contributed by James Demmel, Deaglan Halligan, Yozo Hida and -- */ /* -- Jason Riedy of Univ. of California Berkeley. -- */ /* -- April 2009 -- */ /* -- LAPACK is a software package provided by Univ. of Tennessee, -- */ /* -- Univ. of California Berkeley and NAG Ltd. -- */ /* .. */ /* .. Scalar Arguments .. */ /* .. */ /* .. Array Arguments .. */ /* .. */ /* Purpose */ /* ======= */ /* ZGBRFSX improves the computed solution to a system of linear */ /* equations and provides error bounds and backward error estimates */ /* for the solution. In addition to normwise error bound, the code */ /* provides maximum componentwise error bound if possible. See */ /* comments for ERR_BNDS_NORM and ERR_BNDS_COMP for details of the */ /* error bounds. */ /* The original system of linear equations may have been equilibrated */ /* before calling this routine, as described by arguments EQUED, R */ /* and C below. In this case, the solution and error bounds returned */ /* are for the original unequilibrated system. */ /* Arguments */ /* ========= */ /* Some optional parameters are bundled in the PARAMS array. These */ /* settings determine how refinement is performed, but often the */ /* defaults are acceptable. If the defaults are acceptable, users */ /* can pass NPARAMS = 0 which prevents the source code from accessing */ /* the PARAMS argument. */ /* TRANS (input) 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 = Transpose) */ /* EQUED (input) CHARACTER*1 */ /* Specifies the form of equilibration that was done to A */ /* before calling this routine. This is needed to compute */ /* the solution and error bounds correctly. */ /* = 'N': No equilibration */ /* = '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). */ /* The right hand side B has been changed accordingly. */ /* N (input) INTEGER */ /* The order of the matrix A. N >= 0. */ /* KL (input) INTEGER */ /* The number of subdiagonals within the band of A. KL >= 0. */ /* KU (input) INTEGER */ /* The number of superdiagonals within the band of A. KU >= 0. */ /* NRHS (input) INTEGER */ /* The number of right hand sides, i.e., the number of columns */ /* of the matrices B and X. NRHS >= 0. */ /* AB (input) DOUBLE PRECISION array, dimension (LDAB,N) */ /* The original band matrix A, stored 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). */ /* LDAB (input) INTEGER */ /* The leading dimension of the array AB. LDAB >= KL+KU+1. */ /* AFB (input) DOUBLE PRECISION array, dimension (LDAFB,N) */ /* Details of the LU factorization of the band matrix A, as */ /* computed by DGBTRF. 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. */ /* LDAFB (input) INTEGER */ /* The leading dimension of the array AFB. LDAFB >= 2*KL*KU+1. */ /* IPIV (input) INTEGER array, dimension (N) */ /* The pivot indices from DGETRF; for 1<=i<=N, row i of the */ /* matrix was interchanged with row IPIV(i). */ /* R (input or output) 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. */ /* If R is output, each element of R is a power of the radix. */ /* If R is input, each element of R should be a power of the radix */ /* to ensure a reliable solution and error estimates. Scaling by */ /* powers of the radix does not cause rounding errors unless the */ /* result underflows or overflows. Rounding errors during scaling */ /* lead to refining with a matrix that is not equivalent to the */ /* input matrix, producing error estimates that may not be */ /* reliable. */ /* C (input or output) 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. */ /* If C is output, each element of C is a power of the radix. */ /* If C is input, each element of C should be a power of the radix */ /* to ensure a reliable solution and error estimates. Scaling by */ /* powers of the radix does not cause rounding errors unless the */ /* result underflows or overflows. Rounding errors during scaling */ /* lead to refining with a matrix that is not equivalent to the */ /* input matrix, producing error estimates that may not be */ /* reliable. */ /* B (input) DOUBLE PRECISION array, dimension (LDB,NRHS) */ /* The right hand side matrix B. */ /* LDB (input) INTEGER */ /* The leading dimension of the array B. LDB >= max(1,N). */ /* X (input/output) DOUBLE PRECISION array, dimension (LDX,NRHS) */ /* On entry, the solution matrix X, as computed by DGETRS. */ /* On exit, the improved solution matrix X. */ /* LDX (input) INTEGER */ /* The leading dimension of the array X. LDX >= max(1,N). */ /* RCOND (output) DOUBLE PRECISION */ /* Reciprocal scaled condition number. This is an estimate of the */ /* reciprocal Skeel condition number of the matrix A after */ /* equilibration (if done). If this is less than the machine */ /* precision (in particular, if it is zero), the matrix is singular */ /* to working precision. Note that the error may still be small even */ /* if this number is very small and the matrix appears ill- */ /* conditioned. */ /* BERR (output) DOUBLE PRECISION array, dimension (NRHS) */ /* Componentwise relative backward error. This is 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). */ /* N_ERR_BNDS (input) INTEGER */ /* Number of error bounds to return for each right hand side */ /* and each type (normwise or componentwise). See ERR_BNDS_NORM and */ /* ERR_BNDS_COMP below. */ /* ERR_BNDS_NORM (output) DOUBLE PRECISION array, dimension (NRHS, N_ERR_BNDS) */ /* For each right-hand side, this array contains information about */ /* various error bounds and condition numbers corresponding to the */ /* normwise relative error, which is defined as follows: */ /* Normwise relative error in the ith solution vector: */ /* max_j (abs(XTRUE(j,i) - X(j,i))) */ /* ------------------------------ */ /* max_j abs(X(j,i)) */ /* The array is indexed by the type of error information as described */ /* below. There currently are up to three pieces of information */ /* returned. */ /* The first index in ERR_BNDS_NORM(i,:) corresponds to the ith */ /* right-hand side. */ /* The second index in ERR_BNDS_NORM(:,err) contains the following */ /* three fields: */ /* err = 1 "Trust/don't trust" boolean. Trust the answer if the */ /* reciprocal condition number is less than the threshold */ /* sqrt(n) * dlamch('Epsilon'). */ /* err = 2 "Guaranteed" error bound: The estimated forward error, */ /* almost certainly within a factor of 10 of the true error */ /* so long as the next entry is greater than the threshold */ /* sqrt(n) * dlamch('Epsilon'). This error bound should only */ /* be trusted if the previous boolean is true. */ /* err = 3 Reciprocal condition number: Estimated normwise */ /* reciprocal condition number. Compared with the threshold */ /* sqrt(n) * dlamch('Epsilon') to determine if the error */ /* estimate is "guaranteed". These reciprocal condition */ /* numbers are 1 / (norm(Z^{-1},inf) * norm(Z,inf)) for some */ /* appropriately scaled matrix Z. */ /* Let Z = S*A, where S scales each row by a power of the */ /* radix so all absolute row sums of Z are approximately 1. */ /* See Lapack Working Note 165 for further details and extra */ /* cautions. */ /* ERR_BNDS_COMP (output) DOUBLE PRECISION array, dimension (NRHS, N_ERR_BNDS) */ /* For each right-hand side, this array contains information about */ /* various error bounds and condition numbers corresponding to the */ /* componentwise relative error, which is defined as follows: */ /* Componentwise relative error in the ith solution vector: */ /* abs(XTRUE(j,i) - X(j,i)) */ /* max_j ---------------------- */ /* abs(X(j,i)) */ /* The array is indexed by the right-hand side i (on which the */ /* componentwise relative error depends), and the type of error */ /* information as described below. There currently are up to three */ /* pieces of information returned for each right-hand side. If */ /* componentwise accuracy is not requested (PARAMS(3) = 0.0), then */ /* ERR_BNDS_COMP is not accessed. If N_ERR_BNDS .LT. 3, then at most */ /* the first (:,N_ERR_BNDS) entries are returned. */ /* The first index in ERR_BNDS_COMP(i,:) corresponds to the ith */ /* right-hand side. */ /* The second index in ERR_BNDS_COMP(:,err) contains the following */ /* three fields: */ /* err = 1 "Trust/don't trust" boolean. Trust the answer if the */ /* reciprocal condition number is less than the threshold */ /* sqrt(n) * dlamch('Epsilon'). */ /* err = 2 "Guaranteed" error bound: The estimated forward error, */ /* almost certainly within a factor of 10 of the true error */ /* so long as the next entry is greater than the threshold */ /* sqrt(n) * dlamch('Epsilon'). This error bound should only */ /* be trusted if the previous boolean is true. */ /* err = 3 Reciprocal condition number: Estimated componentwise */ /* reciprocal condition number. Compared with the threshold */ /* sqrt(n) * dlamch('Epsilon') to determine if the error */ /* estimate is "guaranteed". These reciprocal condition */ /* numbers are 1 / (norm(Z^{-1},inf) * norm(Z,inf)) for some */ /* appropriately scaled matrix Z. */ /* Let Z = S*(A*diag(x)), where x is the solution for the */ /* current right-hand side and S scales each row of */ /* A*diag(x) by a power of the radix so all absolute row */ /* sums of Z are approximately 1. */ /* See Lapack Working Note 165 for further details and extra */ /* cautions. */ /* NPARAMS (input) INTEGER */ /* Specifies the number of parameters set in PARAMS. If .LE. 0, the */ /* PARAMS array is never referenced and default values are used. */ /* PARAMS (input / output) DOUBLE PRECISION array, dimension NPARAMS */ /* Specifies algorithm parameters. If an entry is .LT. 0.0, then */ /* that entry will be filled with default value used for that */ /* parameter. Only positions up to NPARAMS are accessed; defaults */ /* are used for higher-numbered parameters. */ /* PARAMS(LA_LINRX_ITREF_I = 1) : Whether to perform iterative */ /* refinement or not. */ /* Default: 1.0D+0 */ /* = 0.0 : No refinement is performed, and no error bounds are */ /* computed. */ /* = 1.0 : Use the double-precision refinement algorithm, */ /* possibly with doubled-single computations if the */ /* compilation environment does not support DOUBLE */ /* PRECISION. */ /* (other values are reserved for future use) */ /* PARAMS(LA_LINRX_ITHRESH_I = 2) : Maximum number of residual */ /* computations allowed for refinement. */ /* Default: 10 */ /* Aggressive: Set to 100 to permit convergence using approximate */ /* factorizations or factorizations other than LU. If */ /* the factorization uses a technique other than */ /* Gaussian elimination, the guarantees in */ /* err_bnds_norm and err_bnds_comp may no longer be */ /* trustworthy. */ /* PARAMS(LA_LINRX_CWISE_I = 3) : Flag determining if the code */ /* will attempt to find a solution with small componentwise */ /* relative error in the double-precision algorithm. Positive */ /* is true, 0.0 is false. */ /* Default: 1.0 (attempt componentwise convergence) */ /* WORK (workspace) COMPLEX*16 array, dimension (2*N) */ /* RWORK (workspace) DOUBLE PRECISION array, dimension (2*N) */ /* INFO (output) INTEGER */ /* = 0: Successful exit. The solution to every right-hand side is */ /* guaranteed. */ /* < 0: If INFO = -i, the i-th argument had an illegal value */ /* > 0 and <= N: U(INFO,INFO) 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+J: The solution corresponding to the Jth right-hand side is */ /* not guaranteed. The solutions corresponding to other right- */ /* hand sides K with K > J may not be guaranteed as well, but */ /* only the first such right-hand side is reported. If a small */ /* componentwise error is not requested (PARAMS(3) = 0.0) then */ /* the Jth right-hand side is the first with a normwise error */ /* bound that is not guaranteed (the smallest J such */ /* that ERR_BNDS_NORM(J,1) = 0.0). By default (PARAMS(3) = 1.0) */ /* the Jth right-hand side is the first with either a normwise or */ /* componentwise error bound that is not guaranteed (the smallest */ /* J such that either ERR_BNDS_NORM(J,1) = 0.0 or */ /* ERR_BNDS_COMP(J,1) = 0.0). See the definition of */ /* ERR_BNDS_NORM(:,1) and ERR_BNDS_COMP(:,1). To get information */ /* about all of the right-hand sides check ERR_BNDS_NORM or */ /* ERR_BNDS_COMP. */ /* ================================================================== */ /* .. Parameters .. */ /* .. */ /* .. Local Scalars .. */ /* .. */ /* .. External Subroutines .. */ /* .. */ /* .. Intrinsic Functions .. */ /* .. */ /* .. External Functions .. */ /* .. */ /* .. Executable Statements .. */ /* Check the input parameters. */ /* Parameter adjustments */ err_bnds_comp_dim1 = *nrhs; err_bnds_comp_offset = 1 + err_bnds_comp_dim1; err_bnds_comp__ -= err_bnds_comp_offset; err_bnds_norm_dim1 = *nrhs; err_bnds_norm_offset = 1 + err_bnds_norm_dim1; err_bnds_norm__ -= err_bnds_norm_offset; ab_dim1 = *ldab; ab_offset = 1 + ab_dim1; ab -= ab_offset; afb_dim1 = *ldafb; afb_offset = 1 + afb_dim1; afb -= afb_offset; --ipiv; --r__; --c__; b_dim1 = *ldb; b_offset = 1 + b_dim1; b -= b_offset; x_dim1 = *ldx; x_offset = 1 + x_dim1; x -= x_offset; --berr; --params; --work; --rwork; /* Function Body */ *info = 0; trans_type__ = ilatrans_(trans); ref_type__ = 1; if (*nparams >= 1) { if (params[1] < 0.) { params[1] = 1.; } else { ref_type__ = (integer) params[1]; } } /* Set default parameters. */ illrcond_thresh__ = (doublereal) (*n) * dlamch_("Epsilon"); ithresh = 10; rthresh = .5; unstable_thresh__ = .25; ignore_cwise__ = FALSE_; if (*nparams >= 2) { if (params[2] < 0.) { params[2] = (doublereal) ithresh; } else { ithresh = (integer) params[2]; } } if (*nparams >= 3) { if (params[3] < 0.) { if (ignore_cwise__) { params[3] = 0.; } else { params[3] = 1.; } } else { ignore_cwise__ = params[3] == 0.; } } if (ref_type__ == 0 || *n_err_bnds__ == 0) { n_norms__ = 0; } else if (ignore_cwise__) { n_norms__ = 1; } else { n_norms__ = 2; } notran = lsame_(trans, "N"); rowequ = lsame_(equed, "R") || lsame_(equed, "B"); colequ = lsame_(equed, "C") || lsame_(equed, "B"); /* Test input parameters. */ if (trans_type__ == -1) { *info = -1; } else if (! rowequ && ! colequ && ! lsame_(equed, "N")) { *info = -2; } else if (*n < 0) { *info = -3; } else if (*kl < 0) { *info = -4; } else if (*ku < 0) { *info = -5; } else if (*nrhs < 0) { *info = -6; } else if (*ldab < *kl + *ku + 1) { *info = -8; } else if (*ldafb < (*kl << 1) + *ku + 1) { *info = -10; } else if (*ldb < max(1,*n)) { *info = -13; } else if (*ldx < max(1,*n)) { *info = -15; } if (*info != 0) { i__1 = -(*info); xerbla_("ZGBRFSX", &i__1); return 0; } /* Quick return if possible. */ if (*n == 0 || *nrhs == 0) { *rcond = 1.; i__1 = *nrhs; for (j = 1; j <= i__1; ++j) { berr[j] = 0.; if (*n_err_bnds__ >= 1) { err_bnds_norm__[j + err_bnds_norm_dim1] = 1.; err_bnds_comp__[j + err_bnds_comp_dim1] = 1.; } else if (*n_err_bnds__ >= 2) { err_bnds_norm__[j + (err_bnds_norm_dim1 << 1)] = 0.; err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] = 0.; } else if (*n_err_bnds__ >= 3) { err_bnds_norm__[j + err_bnds_norm_dim1 * 3] = 1.; err_bnds_comp__[j + err_bnds_comp_dim1 * 3] = 1.; } } return 0; } /* Default to failure. */ *rcond = 0.; i__1 = *nrhs; for (j = 1; j <= i__1; ++j) { berr[j] = 1.; if (*n_err_bnds__ >= 1) { err_bnds_norm__[j + err_bnds_norm_dim1] = 1.; err_bnds_comp__[j + err_bnds_comp_dim1] = 1.; } else if (*n_err_bnds__ >= 2) { err_bnds_norm__[j + (err_bnds_norm_dim1 << 1)] = 1.; err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] = 1.; } else if (*n_err_bnds__ >= 3) { err_bnds_norm__[j + err_bnds_norm_dim1 * 3] = 0.; err_bnds_comp__[j + err_bnds_comp_dim1 * 3] = 0.; } } /* Compute the norm of A and the reciprocal of the condition */ /* number of A. */ if (notran) { *(unsigned char *)norm = 'I'; } else { *(unsigned char *)norm = '1'; } anorm = zlangb_(norm, n, kl, ku, &ab[ab_offset], ldab, &rwork[1]); zgbcon_(norm, n, kl, ku, &afb[afb_offset], ldafb, &ipiv[1], &anorm, rcond, &work[1], &rwork[1], info); /* Perform refinement on each right-hand side */ if (ref_type__ != 0) { prec_type__ = ilaprec_("E"); if (notran) { zla_gbrfsx_extended__(&prec_type__, &trans_type__, n, kl, ku, nrhs, &ab[ab_offset], ldab, &afb[afb_offset], ldafb, & ipiv[1], &colequ, &c__[1], &b[b_offset], ldb, &x[x_offset] , ldx, &berr[1], &n_norms__, &err_bnds_norm__[ err_bnds_norm_offset], &err_bnds_comp__[ err_bnds_comp_offset], &work[1], &rwork[1], &work[*n + 1], (doublecomplex *)(&rwork[1]), rcond, &ithresh, &rthresh, &unstable_thresh__, & ignore_cwise__, info); } else { zla_gbrfsx_extended__(&prec_type__, &trans_type__, n, kl, ku, nrhs, &ab[ab_offset], ldab, &afb[afb_offset], ldafb, & ipiv[1], &rowequ, &r__[1], &b[b_offset], ldb, &x[x_offset] , ldx, &berr[1], &n_norms__, &err_bnds_norm__[ err_bnds_norm_offset], &err_bnds_comp__[ err_bnds_comp_offset], &work[1], &rwork[1], &work[*n + 1], (doublecomplex *)(&rwork[1]), rcond, &ithresh, &rthresh, &unstable_thresh__, & ignore_cwise__, info); } } /* Computing MAX */ d__1 = 10., d__2 = sqrt((doublereal) (*n)); err_lbnd__ = max(d__1,d__2) * dlamch_("Epsilon"); if (*n_err_bnds__ >= 1 && n_norms__ >= 1) { /* Compute scaled normwise condition number cond(A*C). */ if (colequ && notran) { rcond_tmp__ = zla_gbrcond_c__(trans, n, kl, ku, &ab[ab_offset], ldab, &afb[afb_offset], ldafb, &ipiv[1], &c__[1], &c_true, info, &work[1], &rwork[1], (ftnlen)1); } else if (rowequ && ! notran) { rcond_tmp__ = zla_gbrcond_c__(trans, n, kl, ku, &ab[ab_offset], ldab, &afb[afb_offset], ldafb, &ipiv[1], &r__[1], &c_true, info, &work[1], &rwork[1], (ftnlen)1); } else { rcond_tmp__ = zla_gbrcond_c__(trans, n, kl, ku, &ab[ab_offset], ldab, &afb[afb_offset], ldafb, &ipiv[1], &c__[1], & c_false, info, &work[1], &rwork[1], (ftnlen)1); } i__1 = *nrhs; for (j = 1; j <= i__1; ++j) { /* Cap the error at 1.0. */ if (*n_err_bnds__ >= 2 && err_bnds_norm__[j + (err_bnds_norm_dim1 << 1)] > 1.) { err_bnds_norm__[j + (err_bnds_norm_dim1 << 1)] = 1.; } /* Threshold the error (see LAWN). */ if (rcond_tmp__ < illrcond_thresh__) { err_bnds_norm__[j + (err_bnds_norm_dim1 << 1)] = 1.; err_bnds_norm__[j + err_bnds_norm_dim1] = 0.; if (*info <= *n) { *info = *n + j; } } else if (err_bnds_norm__[j + (err_bnds_norm_dim1 << 1)] < err_lbnd__) { err_bnds_norm__[j + (err_bnds_norm_dim1 << 1)] = err_lbnd__; err_bnds_norm__[j + err_bnds_norm_dim1] = 1.; } /* Save the condition number. */ if (*n_err_bnds__ >= 3) { err_bnds_norm__[j + err_bnds_norm_dim1 * 3] = rcond_tmp__; } } } if (*n_err_bnds__ >= 1 && n_norms__ >= 2) { /* Compute componentwise condition number cond(A*diag(Y(:,J))) for */ /* each right-hand side using the current solution as an estimate of */ /* the true solution. If the componentwise error estimate is too */ /* large, then the solution is a lousy estimate of truth and the */ /* estimated RCOND may be too optimistic. To avoid misleading users, */ /* the inverse condition number is set to 0.0 when the estimated */ /* cwise error is at least CWISE_WRONG. */ cwise_wrong__ = sqrt(dlamch_("Epsilon")); i__1 = *nrhs; for (j = 1; j <= i__1; ++j) { if (err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] < cwise_wrong__) { rcond_tmp__ = zla_gbrcond_x__(trans, n, kl, ku, &ab[ab_offset] , ldab, &afb[afb_offset], ldafb, &ipiv[1], &x[j * x_dim1 + 1], info, &work[1], &rwork[1], (ftnlen)1); } else { rcond_tmp__ = 0.; } /* Cap the error at 1.0. */ if (*n_err_bnds__ >= 2 && err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] > 1.) { err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] = 1.; } /* Threshold the error (see LAWN). */ if (rcond_tmp__ < illrcond_thresh__) { err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] = 1.; err_bnds_comp__[j + err_bnds_comp_dim1] = 0.; if (params[3] == 1. && *info < *n + j) { *info = *n + j; } } else if (err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] < err_lbnd__) { err_bnds_comp__[j + (err_bnds_comp_dim1 << 1)] = err_lbnd__; err_bnds_comp__[j + err_bnds_comp_dim1] = 1.; } /* Save the condition number. */ if (*n_err_bnds__ >= 3) { err_bnds_comp__[j + err_bnds_comp_dim1 * 3] = rcond_tmp__; } } } return 0; /* End of ZGBRFSX */ } /* zgbrfsx_ */