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author | shmel1k <shmel1k@ydb.tech> | 2022-09-02 12:44:59 +0300 |
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committer | shmel1k <shmel1k@ydb.tech> | 2022-09-02 12:44:59 +0300 |
commit | 90d450f74722da7859d6f510a869f6c6908fd12f (patch) | |
tree | 538c718dedc76cdfe37ad6d01ff250dd930d9278 /contrib/libs/clapack/zlatrs.c | |
parent | 01f64c1ecd0d4ffa9e3a74478335f1745f26cc75 (diff) | |
download | ydb-90d450f74722da7859d6f510a869f6c6908fd12f.tar.gz |
[] add metering mode to CLI
Diffstat (limited to 'contrib/libs/clapack/zlatrs.c')
-rw-r--r-- | contrib/libs/clapack/zlatrs.c | 1150 |
1 files changed, 1150 insertions, 0 deletions
diff --git a/contrib/libs/clapack/zlatrs.c b/contrib/libs/clapack/zlatrs.c new file mode 100644 index 0000000000..06fe9bb832 --- /dev/null +++ b/contrib/libs/clapack/zlatrs.c @@ -0,0 +1,1150 @@ +/* zlatrs.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 integer c__1 = 1; +static doublereal c_b36 = .5; + +/* Subroutine */ int zlatrs_(char *uplo, char *trans, char *diag, char * + normin, integer *n, doublecomplex *a, integer *lda, doublecomplex *x, + doublereal *scale, doublereal *cnorm, integer *info) +{ + /* System generated locals */ + integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5; + doublereal d__1, d__2, d__3, d__4; + doublecomplex z__1, z__2, z__3, z__4; + + /* Builtin functions */ + double d_imag(doublecomplex *); + void d_cnjg(doublecomplex *, doublecomplex *); + + /* Local variables */ + integer i__, j; + doublereal xj, rec, tjj; + integer jinc; + doublereal xbnd; + integer imax; + doublereal tmax; + doublecomplex tjjs; + doublereal xmax, grow; + extern /* Subroutine */ int dscal_(integer *, doublereal *, doublereal *, + integer *); + extern logical lsame_(char *, char *); + doublereal tscal; + doublecomplex uscal; + integer jlast; + doublecomplex csumj; + extern /* Double Complex */ VOID zdotc_(doublecomplex *, integer *, + doublecomplex *, integer *, doublecomplex *, integer *); + logical upper; + extern /* Double Complex */ VOID zdotu_(doublecomplex *, integer *, + doublecomplex *, integer *, doublecomplex *, integer *); + extern /* Subroutine */ int zaxpy_(integer *, doublecomplex *, + doublecomplex *, integer *, doublecomplex *, integer *), ztrsv_( + char *, char *, char *, integer *, doublecomplex *, integer *, + doublecomplex *, integer *), dlabad_( + doublereal *, doublereal *); + extern doublereal dlamch_(char *); + extern integer idamax_(integer *, doublereal *, integer *); + extern /* Subroutine */ int xerbla_(char *, integer *), zdscal_( + integer *, doublereal *, doublecomplex *, integer *); + doublereal bignum; + extern integer izamax_(integer *, doublecomplex *, integer *); + extern /* Double Complex */ VOID zladiv_(doublecomplex *, doublecomplex *, + doublecomplex *); + logical notran; + integer jfirst; + extern doublereal dzasum_(integer *, doublecomplex *, integer *); + doublereal smlnum; + logical nounit; + + +/* -- LAPACK auxiliary routine (version 3.2) -- */ +/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */ +/* November 2006 */ + +/* .. Scalar Arguments .. */ +/* .. */ +/* .. Array Arguments .. */ +/* .. */ + +/* Purpose */ +/* ======= */ + +/* ZLATRS solves one of the triangular systems */ + +/* A * x = s*b, A**T * x = s*b, or A**H * x = s*b, */ + +/* with scaling to prevent overflow. Here A is an upper or lower */ +/* triangular matrix, A**T denotes the transpose of A, A**H denotes the */ +/* conjugate transpose of A, x and b are n-element vectors, and s is a */ +/* scaling factor, usually less than or equal to 1, chosen so that the */ +/* components of x will be less than the overflow threshold. If the */ +/* unscaled problem will not cause overflow, the Level 2 BLAS routine */ +/* ZTRSV is called. If the matrix A is singular (A(j,j) = 0 for some j), */ +/* then s is set to 0 and a non-trivial solution to A*x = 0 is returned. */ + +/* Arguments */ +/* ========= */ + +/* UPLO (input) CHARACTER*1 */ +/* Specifies whether the matrix A is upper or lower triangular. */ +/* = 'U': Upper triangular */ +/* = 'L': Lower triangular */ + +/* TRANS (input) CHARACTER*1 */ +/* Specifies the operation applied to A. */ +/* = 'N': Solve A * x = s*b (No transpose) */ +/* = 'T': Solve A**T * x = s*b (Transpose) */ +/* = 'C': Solve A**H * x = s*b (Conjugate transpose) */ + +/* DIAG (input) CHARACTER*1 */ +/* Specifies whether or not the matrix A is unit triangular. */ +/* = 'N': Non-unit triangular */ +/* = 'U': Unit triangular */ + +/* NORMIN (input) CHARACTER*1 */ +/* Specifies whether CNORM has been set or not. */ +/* = 'Y': CNORM contains the column norms on entry */ +/* = 'N': CNORM is not set on entry. On exit, the norms will */ +/* be computed and stored in CNORM. */ + +/* N (input) INTEGER */ +/* The order of the matrix A. N >= 0. */ + +/* A (input) COMPLEX*16 array, dimension (LDA,N) */ +/* The triangular matrix A. If UPLO = 'U', the leading n by n */ +/* upper triangular part of the array A contains the upper */ +/* triangular matrix, and the strictly lower triangular part of */ +/* A is not referenced. If UPLO = 'L', the leading n by n lower */ +/* triangular part of the array A contains the lower triangular */ +/* matrix, and the strictly upper triangular part of A is not */ +/* referenced. If DIAG = 'U', the diagonal elements of A are */ +/* also not referenced and are assumed to be 1. */ + +/* LDA (input) INTEGER */ +/* The leading dimension of the array A. LDA >= max (1,N). */ + +/* X (input/output) COMPLEX*16 array, dimension (N) */ +/* On entry, the right hand side b of the triangular system. */ +/* On exit, X is overwritten by the solution vector x. */ + +/* SCALE (output) DOUBLE PRECISION */ +/* The scaling factor s for the triangular system */ +/* A * x = s*b, A**T * x = s*b, or A**H * x = s*b. */ +/* If SCALE = 0, the matrix A is singular or badly scaled, and */ +/* the vector x is an exact or approximate solution to A*x = 0. */ + +/* CNORM (input or output) DOUBLE PRECISION array, dimension (N) */ + +/* If NORMIN = 'Y', CNORM is an input argument and CNORM(j) */ +/* contains the norm of the off-diagonal part of the j-th column */ +/* of A. If TRANS = 'N', CNORM(j) must be greater than or equal */ +/* to the infinity-norm, and if TRANS = 'T' or 'C', CNORM(j) */ +/* must be greater than or equal to the 1-norm. */ + +/* If NORMIN = 'N', CNORM is an output argument and CNORM(j) */ +/* returns the 1-norm of the offdiagonal part of the j-th column */ +/* of A. */ + +/* INFO (output) INTEGER */ +/* = 0: successful exit */ +/* < 0: if INFO = -k, the k-th argument had an illegal value */ + +/* Further Details */ +/* ======= ======= */ + +/* A rough bound on x is computed; if that is less than overflow, ZTRSV */ +/* is called, otherwise, specific code is used which checks for possible */ +/* overflow or divide-by-zero at every operation. */ + +/* A columnwise scheme is used for solving A*x = b. The basic algorithm */ +/* if A is lower triangular is */ + +/* x[1:n] := b[1:n] */ +/* for j = 1, ..., n */ +/* x(j) := x(j) / A(j,j) */ +/* x[j+1:n] := x[j+1:n] - x(j) * A[j+1:n,j] */ +/* end */ + +/* Define bounds on the components of x after j iterations of the loop: */ +/* M(j) = bound on x[1:j] */ +/* G(j) = bound on x[j+1:n] */ +/* Initially, let M(0) = 0 and G(0) = max{x(i), i=1,...,n}. */ + +/* Then for iteration j+1 we have */ +/* M(j+1) <= G(j) / | A(j+1,j+1) | */ +/* G(j+1) <= G(j) + M(j+1) * | A[j+2:n,j+1] | */ +/* <= G(j) ( 1 + CNORM(j+1) / | A(j+1,j+1) | ) */ + +/* where CNORM(j+1) is greater than or equal to the infinity-norm of */ +/* column j+1 of A, not counting the diagonal. Hence */ + +/* G(j) <= G(0) product ( 1 + CNORM(i) / | A(i,i) | ) */ +/* 1<=i<=j */ +/* and */ + +/* |x(j)| <= ( G(0) / |A(j,j)| ) product ( 1 + CNORM(i) / |A(i,i)| ) */ +/* 1<=i< j */ + +/* Since |x(j)| <= M(j), we use the Level 2 BLAS routine ZTRSV if the */ +/* reciprocal of the largest M(j), j=1,..,n, is larger than */ +/* max(underflow, 1/overflow). */ + +/* The bound on x(j) is also used to determine when a step in the */ +/* columnwise method can be performed without fear of overflow. If */ +/* the computed bound is greater than a large constant, x is scaled to */ +/* prevent overflow, but if the bound overflows, x is set to 0, x(j) to */ +/* 1, and scale to 0, and a non-trivial solution to A*x = 0 is found. */ + +/* Similarly, a row-wise scheme is used to solve A**T *x = b or */ +/* A**H *x = b. The basic algorithm for A upper triangular is */ + +/* for j = 1, ..., n */ +/* x(j) := ( b(j) - A[1:j-1,j]' * x[1:j-1] ) / A(j,j) */ +/* end */ + +/* We simultaneously compute two bounds */ +/* G(j) = bound on ( b(i) - A[1:i-1,i]' * x[1:i-1] ), 1<=i<=j */ +/* M(j) = bound on x(i), 1<=i<=j */ + +/* The initial values are G(0) = 0, M(0) = max{b(i), i=1,..,n}, and we */ +/* add the constraint G(j) >= G(j-1) and M(j) >= M(j-1) for j >= 1. */ +/* Then the bound on x(j) is */ + +/* M(j) <= M(j-1) * ( 1 + CNORM(j) ) / | A(j,j) | */ + +/* <= M(0) * product ( ( 1 + CNORM(i) ) / |A(i,i)| ) */ +/* 1<=i<=j */ + +/* and we can safely call ZTRSV if 1/M(n) and 1/G(n) are both greater */ +/* than max(underflow, 1/overflow). */ + +/* ===================================================================== */ + +/* .. Parameters .. */ +/* .. */ +/* .. Local Scalars .. */ +/* .. */ +/* .. External Functions .. */ +/* .. */ +/* .. External Subroutines .. */ +/* .. */ +/* .. Intrinsic Functions .. */ +/* .. */ +/* .. Statement Functions .. */ +/* .. */ +/* .. Statement Function definitions .. */ +/* .. */ +/* .. Executable Statements .. */ + + /* Parameter adjustments */ + a_dim1 = *lda; + a_offset = 1 + a_dim1; + a -= a_offset; + --x; + --cnorm; + + /* Function Body */ + *info = 0; + upper = lsame_(uplo, "U"); + notran = lsame_(trans, "N"); + nounit = lsame_(diag, "N"); + +/* Test the input parameters. */ + + if (! upper && ! lsame_(uplo, "L")) { + *info = -1; + } else if (! notran && ! lsame_(trans, "T") && ! + lsame_(trans, "C")) { + *info = -2; + } else if (! nounit && ! lsame_(diag, "U")) { + *info = -3; + } else if (! lsame_(normin, "Y") && ! lsame_(normin, + "N")) { + *info = -4; + } else if (*n < 0) { + *info = -5; + } else if (*lda < max(1,*n)) { + *info = -7; + } + if (*info != 0) { + i__1 = -(*info); + xerbla_("ZLATRS", &i__1); + return 0; + } + +/* Quick return if possible */ + + if (*n == 0) { + return 0; + } + +/* Determine machine dependent parameters to control overflow. */ + + smlnum = dlamch_("Safe minimum"); + bignum = 1. / smlnum; + dlabad_(&smlnum, &bignum); + smlnum /= dlamch_("Precision"); + bignum = 1. / smlnum; + *scale = 1.; + + if (lsame_(normin, "N")) { + +/* Compute the 1-norm of each column, not including the diagonal. */ + + if (upper) { + +/* A is upper triangular. */ + + i__1 = *n; + for (j = 1; j <= i__1; ++j) { + i__2 = j - 1; + cnorm[j] = dzasum_(&i__2, &a[j * a_dim1 + 1], &c__1); +/* L10: */ + } + } else { + +/* A is lower triangular. */ + + i__1 = *n - 1; + for (j = 1; j <= i__1; ++j) { + i__2 = *n - j; + cnorm[j] = dzasum_(&i__2, &a[j + 1 + j * a_dim1], &c__1); +/* L20: */ + } + cnorm[*n] = 0.; + } + } + +/* Scale the column norms by TSCAL if the maximum element in CNORM is */ +/* greater than BIGNUM/2. */ + + imax = idamax_(n, &cnorm[1], &c__1); + tmax = cnorm[imax]; + if (tmax <= bignum * .5) { + tscal = 1.; + } else { + tscal = .5 / (smlnum * tmax); + dscal_(n, &tscal, &cnorm[1], &c__1); + } + +/* Compute a bound on the computed solution vector to see if the */ +/* Level 2 BLAS routine ZTRSV can be used. */ + + xmax = 0.; + i__1 = *n; + for (j = 1; j <= i__1; ++j) { +/* Computing MAX */ + i__2 = j; + d__3 = xmax, d__4 = (d__1 = x[i__2].r / 2., abs(d__1)) + (d__2 = + d_imag(&x[j]) / 2., abs(d__2)); + xmax = max(d__3,d__4); +/* L30: */ + } + xbnd = xmax; + + if (notran) { + +/* Compute the growth in A * x = b. */ + + if (upper) { + jfirst = *n; + jlast = 1; + jinc = -1; + } else { + jfirst = 1; + jlast = *n; + jinc = 1; + } + + if (tscal != 1.) { + grow = 0.; + goto L60; + } + + if (nounit) { + +/* A is non-unit triangular. */ + +/* Compute GROW = 1/G(j) and XBND = 1/M(j). */ +/* Initially, G(0) = max{x(i), i=1,...,n}. */ + + grow = .5 / max(xbnd,smlnum); + xbnd = grow; + i__1 = jlast; + i__2 = jinc; + for (j = jfirst; i__2 < 0 ? j >= i__1 : j <= i__1; j += i__2) { + +/* Exit the loop if the growth factor is too small. */ + + if (grow <= smlnum) { + goto L60; + } + + i__3 = j + j * a_dim1; + tjjs.r = a[i__3].r, tjjs.i = a[i__3].i; + tjj = (d__1 = tjjs.r, abs(d__1)) + (d__2 = d_imag(&tjjs), abs( + d__2)); + + if (tjj >= smlnum) { + +/* M(j) = G(j-1) / abs(A(j,j)) */ + +/* Computing MIN */ + d__1 = xbnd, d__2 = min(1.,tjj) * grow; + xbnd = min(d__1,d__2); + } else { + +/* M(j) could overflow, set XBND to 0. */ + + xbnd = 0.; + } + + if (tjj + cnorm[j] >= smlnum) { + +/* G(j) = G(j-1)*( 1 + CNORM(j) / abs(A(j,j)) ) */ + + grow *= tjj / (tjj + cnorm[j]); + } else { + +/* G(j) could overflow, set GROW to 0. */ + + grow = 0.; + } +/* L40: */ + } + grow = xbnd; + } else { + +/* A is unit triangular. */ + +/* Compute GROW = 1/G(j), where G(0) = max{x(i), i=1,...,n}. */ + +/* Computing MIN */ + d__1 = 1., d__2 = .5 / max(xbnd,smlnum); + grow = min(d__1,d__2); + i__2 = jlast; + i__1 = jinc; + for (j = jfirst; i__1 < 0 ? j >= i__2 : j <= i__2; j += i__1) { + +/* Exit the loop if the growth factor is too small. */ + + if (grow <= smlnum) { + goto L60; + } + +/* G(j) = G(j-1)*( 1 + CNORM(j) ) */ + + grow *= 1. / (cnorm[j] + 1.); +/* L50: */ + } + } +L60: + + ; + } else { + +/* Compute the growth in A**T * x = b or A**H * x = b. */ + + if (upper) { + jfirst = 1; + jlast = *n; + jinc = 1; + } else { + jfirst = *n; + jlast = 1; + jinc = -1; + } + + if (tscal != 1.) { + grow = 0.; + goto L90; + } + + if (nounit) { + +/* A is non-unit triangular. */ + +/* Compute GROW = 1/G(j) and XBND = 1/M(j). */ +/* Initially, M(0) = max{x(i), i=1,...,n}. */ + + grow = .5 / max(xbnd,smlnum); + xbnd = grow; + i__1 = jlast; + i__2 = jinc; + for (j = jfirst; i__2 < 0 ? j >= i__1 : j <= i__1; j += i__2) { + +/* Exit the loop if the growth factor is too small. */ + + if (grow <= smlnum) { + goto L90; + } + +/* G(j) = max( G(j-1), M(j-1)*( 1 + CNORM(j) ) ) */ + + xj = cnorm[j] + 1.; +/* Computing MIN */ + d__1 = grow, d__2 = xbnd / xj; + grow = min(d__1,d__2); + + i__3 = j + j * a_dim1; + tjjs.r = a[i__3].r, tjjs.i = a[i__3].i; + tjj = (d__1 = tjjs.r, abs(d__1)) + (d__2 = d_imag(&tjjs), abs( + d__2)); + + if (tjj >= smlnum) { + +/* M(j) = M(j-1)*( 1 + CNORM(j) ) / abs(A(j,j)) */ + + if (xj > tjj) { + xbnd *= tjj / xj; + } + } else { + +/* M(j) could overflow, set XBND to 0. */ + + xbnd = 0.; + } +/* L70: */ + } + grow = min(grow,xbnd); + } else { + +/* A is unit triangular. */ + +/* Compute GROW = 1/G(j), where G(0) = max{x(i), i=1,...,n}. */ + +/* Computing MIN */ + d__1 = 1., d__2 = .5 / max(xbnd,smlnum); + grow = min(d__1,d__2); + i__2 = jlast; + i__1 = jinc; + for (j = jfirst; i__1 < 0 ? j >= i__2 : j <= i__2; j += i__1) { + +/* Exit the loop if the growth factor is too small. */ + + if (grow <= smlnum) { + goto L90; + } + +/* G(j) = ( 1 + CNORM(j) )*G(j-1) */ + + xj = cnorm[j] + 1.; + grow /= xj; +/* L80: */ + } + } +L90: + ; + } + + if (grow * tscal > smlnum) { + +/* Use the Level 2 BLAS solve if the reciprocal of the bound on */ +/* elements of X is not too small. */ + + ztrsv_(uplo, trans, diag, n, &a[a_offset], lda, &x[1], &c__1); + } else { + +/* Use a Level 1 BLAS solve, scaling intermediate results. */ + + if (xmax > bignum * .5) { + +/* Scale X so that its components are less than or equal to */ +/* BIGNUM in absolute value. */ + + *scale = bignum * .5 / xmax; + zdscal_(n, scale, &x[1], &c__1); + xmax = bignum; + } else { + xmax *= 2.; + } + + if (notran) { + +/* Solve A * x = b */ + + i__1 = jlast; + i__2 = jinc; + for (j = jfirst; i__2 < 0 ? j >= i__1 : j <= i__1; j += i__2) { + +/* Compute x(j) = b(j) / A(j,j), scaling x if necessary. */ + + i__3 = j; + xj = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[j]), + abs(d__2)); + if (nounit) { + i__3 = j + j * a_dim1; + z__1.r = tscal * a[i__3].r, z__1.i = tscal * a[i__3].i; + tjjs.r = z__1.r, tjjs.i = z__1.i; + } else { + tjjs.r = tscal, tjjs.i = 0.; + if (tscal == 1.) { + goto L110; + } + } + tjj = (d__1 = tjjs.r, abs(d__1)) + (d__2 = d_imag(&tjjs), abs( + d__2)); + if (tjj > smlnum) { + +/* abs(A(j,j)) > SMLNUM: */ + + if (tjj < 1.) { + if (xj > tjj * bignum) { + +/* Scale x by 1/b(j). */ + + rec = 1. / xj; + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + xmax *= rec; + } + } + i__3 = j; + zladiv_(&z__1, &x[j], &tjjs); + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + i__3 = j; + xj = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[j]) + , abs(d__2)); + } else if (tjj > 0.) { + +/* 0 < abs(A(j,j)) <= SMLNUM: */ + + if (xj > tjj * bignum) { + +/* Scale x by (1/abs(x(j)))*abs(A(j,j))*BIGNUM */ +/* to avoid overflow when dividing by A(j,j). */ + + rec = tjj * bignum / xj; + if (cnorm[j] > 1.) { + +/* Scale by 1/CNORM(j) to avoid overflow when */ +/* multiplying x(j) times column j. */ + + rec /= cnorm[j]; + } + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + xmax *= rec; + } + i__3 = j; + zladiv_(&z__1, &x[j], &tjjs); + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + i__3 = j; + xj = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[j]) + , abs(d__2)); + } else { + +/* A(j,j) = 0: Set x(1:n) = 0, x(j) = 1, and */ +/* scale = 0, and compute a solution to A*x = 0. */ + + i__3 = *n; + for (i__ = 1; i__ <= i__3; ++i__) { + i__4 = i__; + x[i__4].r = 0., x[i__4].i = 0.; +/* L100: */ + } + i__3 = j; + x[i__3].r = 1., x[i__3].i = 0.; + xj = 1.; + *scale = 0.; + xmax = 0.; + } +L110: + +/* Scale x if necessary to avoid overflow when adding a */ +/* multiple of column j of A. */ + + if (xj > 1.) { + rec = 1. / xj; + if (cnorm[j] > (bignum - xmax) * rec) { + +/* Scale x by 1/(2*abs(x(j))). */ + + rec *= .5; + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + } + } else if (xj * cnorm[j] > bignum - xmax) { + +/* Scale x by 1/2. */ + + zdscal_(n, &c_b36, &x[1], &c__1); + *scale *= .5; + } + + if (upper) { + if (j > 1) { + +/* Compute the update */ +/* x(1:j-1) := x(1:j-1) - x(j) * A(1:j-1,j) */ + + i__3 = j - 1; + i__4 = j; + z__2.r = -x[i__4].r, z__2.i = -x[i__4].i; + z__1.r = tscal * z__2.r, z__1.i = tscal * z__2.i; + zaxpy_(&i__3, &z__1, &a[j * a_dim1 + 1], &c__1, &x[1], + &c__1); + i__3 = j - 1; + i__ = izamax_(&i__3, &x[1], &c__1); + i__3 = i__; + xmax = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag( + &x[i__]), abs(d__2)); + } + } else { + if (j < *n) { + +/* Compute the update */ +/* x(j+1:n) := x(j+1:n) - x(j) * A(j+1:n,j) */ + + i__3 = *n - j; + i__4 = j; + z__2.r = -x[i__4].r, z__2.i = -x[i__4].i; + z__1.r = tscal * z__2.r, z__1.i = tscal * z__2.i; + zaxpy_(&i__3, &z__1, &a[j + 1 + j * a_dim1], &c__1, & + x[j + 1], &c__1); + i__3 = *n - j; + i__ = j + izamax_(&i__3, &x[j + 1], &c__1); + i__3 = i__; + xmax = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag( + &x[i__]), abs(d__2)); + } + } +/* L120: */ + } + + } else if (lsame_(trans, "T")) { + +/* Solve A**T * x = b */ + + i__2 = jlast; + i__1 = jinc; + for (j = jfirst; i__1 < 0 ? j >= i__2 : j <= i__2; j += i__1) { + +/* Compute x(j) = b(j) - sum A(k,j)*x(k). */ +/* k<>j */ + + i__3 = j; + xj = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[j]), + abs(d__2)); + uscal.r = tscal, uscal.i = 0.; + rec = 1. / max(xmax,1.); + if (cnorm[j] > (bignum - xj) * rec) { + +/* If x(j) could overflow, scale x by 1/(2*XMAX). */ + + rec *= .5; + if (nounit) { + i__3 = j + j * a_dim1; + z__1.r = tscal * a[i__3].r, z__1.i = tscal * a[i__3] + .i; + tjjs.r = z__1.r, tjjs.i = z__1.i; + } else { + tjjs.r = tscal, tjjs.i = 0.; + } + tjj = (d__1 = tjjs.r, abs(d__1)) + (d__2 = d_imag(&tjjs), + abs(d__2)); + if (tjj > 1.) { + +/* Divide by A(j,j) when scaling x if A(j,j) > 1. */ + +/* Computing MIN */ + d__1 = 1., d__2 = rec * tjj; + rec = min(d__1,d__2); + zladiv_(&z__1, &uscal, &tjjs); + uscal.r = z__1.r, uscal.i = z__1.i; + } + if (rec < 1.) { + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + xmax *= rec; + } + } + + csumj.r = 0., csumj.i = 0.; + if (uscal.r == 1. && uscal.i == 0.) { + +/* If the scaling needed for A in the dot product is 1, */ +/* call ZDOTU to perform the dot product. */ + + if (upper) { + i__3 = j - 1; + zdotu_(&z__1, &i__3, &a[j * a_dim1 + 1], &c__1, &x[1], + &c__1); + csumj.r = z__1.r, csumj.i = z__1.i; + } else if (j < *n) { + i__3 = *n - j; + zdotu_(&z__1, &i__3, &a[j + 1 + j * a_dim1], &c__1, & + x[j + 1], &c__1); + csumj.r = z__1.r, csumj.i = z__1.i; + } + } else { + +/* Otherwise, use in-line code for the dot product. */ + + if (upper) { + i__3 = j - 1; + for (i__ = 1; i__ <= i__3; ++i__) { + i__4 = i__ + j * a_dim1; + z__3.r = a[i__4].r * uscal.r - a[i__4].i * + uscal.i, z__3.i = a[i__4].r * uscal.i + a[ + i__4].i * uscal.r; + i__5 = i__; + z__2.r = z__3.r * x[i__5].r - z__3.i * x[i__5].i, + z__2.i = z__3.r * x[i__5].i + z__3.i * x[ + i__5].r; + z__1.r = csumj.r + z__2.r, z__1.i = csumj.i + + z__2.i; + csumj.r = z__1.r, csumj.i = z__1.i; +/* L130: */ + } + } else if (j < *n) { + i__3 = *n; + for (i__ = j + 1; i__ <= i__3; ++i__) { + i__4 = i__ + j * a_dim1; + z__3.r = a[i__4].r * uscal.r - a[i__4].i * + uscal.i, z__3.i = a[i__4].r * uscal.i + a[ + i__4].i * uscal.r; + i__5 = i__; + z__2.r = z__3.r * x[i__5].r - z__3.i * x[i__5].i, + z__2.i = z__3.r * x[i__5].i + z__3.i * x[ + i__5].r; + z__1.r = csumj.r + z__2.r, z__1.i = csumj.i + + z__2.i; + csumj.r = z__1.r, csumj.i = z__1.i; +/* L140: */ + } + } + } + + z__1.r = tscal, z__1.i = 0.; + if (uscal.r == z__1.r && uscal.i == z__1.i) { + +/* Compute x(j) := ( x(j) - CSUMJ ) / A(j,j) if 1/A(j,j) */ +/* was not used to scale the dotproduct. */ + + i__3 = j; + i__4 = j; + z__1.r = x[i__4].r - csumj.r, z__1.i = x[i__4].i - + csumj.i; + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + i__3 = j; + xj = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[j]) + , abs(d__2)); + if (nounit) { + i__3 = j + j * a_dim1; + z__1.r = tscal * a[i__3].r, z__1.i = tscal * a[i__3] + .i; + tjjs.r = z__1.r, tjjs.i = z__1.i; + } else { + tjjs.r = tscal, tjjs.i = 0.; + if (tscal == 1.) { + goto L160; + } + } + +/* Compute x(j) = x(j) / A(j,j), scaling if necessary. */ + + tjj = (d__1 = tjjs.r, abs(d__1)) + (d__2 = d_imag(&tjjs), + abs(d__2)); + if (tjj > smlnum) { + +/* abs(A(j,j)) > SMLNUM: */ + + if (tjj < 1.) { + if (xj > tjj * bignum) { + +/* Scale X by 1/abs(x(j)). */ + + rec = 1. / xj; + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + xmax *= rec; + } + } + i__3 = j; + zladiv_(&z__1, &x[j], &tjjs); + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + } else if (tjj > 0.) { + +/* 0 < abs(A(j,j)) <= SMLNUM: */ + + if (xj > tjj * bignum) { + +/* Scale x by (1/abs(x(j)))*abs(A(j,j))*BIGNUM. */ + + rec = tjj * bignum / xj; + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + xmax *= rec; + } + i__3 = j; + zladiv_(&z__1, &x[j], &tjjs); + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + } else { + +/* A(j,j) = 0: Set x(1:n) = 0, x(j) = 1, and */ +/* scale = 0 and compute a solution to A**T *x = 0. */ + + i__3 = *n; + for (i__ = 1; i__ <= i__3; ++i__) { + i__4 = i__; + x[i__4].r = 0., x[i__4].i = 0.; +/* L150: */ + } + i__3 = j; + x[i__3].r = 1., x[i__3].i = 0.; + *scale = 0.; + xmax = 0.; + } +L160: + ; + } else { + +/* Compute x(j) := x(j) / A(j,j) - CSUMJ if the dot */ +/* product has already been divided by 1/A(j,j). */ + + i__3 = j; + zladiv_(&z__2, &x[j], &tjjs); + z__1.r = z__2.r - csumj.r, z__1.i = z__2.i - csumj.i; + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + } +/* Computing MAX */ + i__3 = j; + d__3 = xmax, d__4 = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = + d_imag(&x[j]), abs(d__2)); + xmax = max(d__3,d__4); +/* L170: */ + } + + } else { + +/* Solve A**H * x = b */ + + i__1 = jlast; + i__2 = jinc; + for (j = jfirst; i__2 < 0 ? j >= i__1 : j <= i__1; j += i__2) { + +/* Compute x(j) = b(j) - sum A(k,j)*x(k). */ +/* k<>j */ + + i__3 = j; + xj = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[j]), + abs(d__2)); + uscal.r = tscal, uscal.i = 0.; + rec = 1. / max(xmax,1.); + if (cnorm[j] > (bignum - xj) * rec) { + +/* If x(j) could overflow, scale x by 1/(2*XMAX). */ + + rec *= .5; + if (nounit) { + d_cnjg(&z__2, &a[j + j * a_dim1]); + z__1.r = tscal * z__2.r, z__1.i = tscal * z__2.i; + tjjs.r = z__1.r, tjjs.i = z__1.i; + } else { + tjjs.r = tscal, tjjs.i = 0.; + } + tjj = (d__1 = tjjs.r, abs(d__1)) + (d__2 = d_imag(&tjjs), + abs(d__2)); + if (tjj > 1.) { + +/* Divide by A(j,j) when scaling x if A(j,j) > 1. */ + +/* Computing MIN */ + d__1 = 1., d__2 = rec * tjj; + rec = min(d__1,d__2); + zladiv_(&z__1, &uscal, &tjjs); + uscal.r = z__1.r, uscal.i = z__1.i; + } + if (rec < 1.) { + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + xmax *= rec; + } + } + + csumj.r = 0., csumj.i = 0.; + if (uscal.r == 1. && uscal.i == 0.) { + +/* If the scaling needed for A in the dot product is 1, */ +/* call ZDOTC to perform the dot product. */ + + if (upper) { + i__3 = j - 1; + zdotc_(&z__1, &i__3, &a[j * a_dim1 + 1], &c__1, &x[1], + &c__1); + csumj.r = z__1.r, csumj.i = z__1.i; + } else if (j < *n) { + i__3 = *n - j; + zdotc_(&z__1, &i__3, &a[j + 1 + j * a_dim1], &c__1, & + x[j + 1], &c__1); + csumj.r = z__1.r, csumj.i = z__1.i; + } + } else { + +/* Otherwise, use in-line code for the dot product. */ + + if (upper) { + i__3 = j - 1; + for (i__ = 1; i__ <= i__3; ++i__) { + d_cnjg(&z__4, &a[i__ + j * a_dim1]); + z__3.r = z__4.r * uscal.r - z__4.i * uscal.i, + z__3.i = z__4.r * uscal.i + z__4.i * + uscal.r; + i__4 = i__; + z__2.r = z__3.r * x[i__4].r - z__3.i * x[i__4].i, + z__2.i = z__3.r * x[i__4].i + z__3.i * x[ + i__4].r; + z__1.r = csumj.r + z__2.r, z__1.i = csumj.i + + z__2.i; + csumj.r = z__1.r, csumj.i = z__1.i; +/* L180: */ + } + } else if (j < *n) { + i__3 = *n; + for (i__ = j + 1; i__ <= i__3; ++i__) { + d_cnjg(&z__4, &a[i__ + j * a_dim1]); + z__3.r = z__4.r * uscal.r - z__4.i * uscal.i, + z__3.i = z__4.r * uscal.i + z__4.i * + uscal.r; + i__4 = i__; + z__2.r = z__3.r * x[i__4].r - z__3.i * x[i__4].i, + z__2.i = z__3.r * x[i__4].i + z__3.i * x[ + i__4].r; + z__1.r = csumj.r + z__2.r, z__1.i = csumj.i + + z__2.i; + csumj.r = z__1.r, csumj.i = z__1.i; +/* L190: */ + } + } + } + + z__1.r = tscal, z__1.i = 0.; + if (uscal.r == z__1.r && uscal.i == z__1.i) { + +/* Compute x(j) := ( x(j) - CSUMJ ) / A(j,j) if 1/A(j,j) */ +/* was not used to scale the dotproduct. */ + + i__3 = j; + i__4 = j; + z__1.r = x[i__4].r - csumj.r, z__1.i = x[i__4].i - + csumj.i; + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + i__3 = j; + xj = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = d_imag(&x[j]) + , abs(d__2)); + if (nounit) { + d_cnjg(&z__2, &a[j + j * a_dim1]); + z__1.r = tscal * z__2.r, z__1.i = tscal * z__2.i; + tjjs.r = z__1.r, tjjs.i = z__1.i; + } else { + tjjs.r = tscal, tjjs.i = 0.; + if (tscal == 1.) { + goto L210; + } + } + +/* Compute x(j) = x(j) / A(j,j), scaling if necessary. */ + + tjj = (d__1 = tjjs.r, abs(d__1)) + (d__2 = d_imag(&tjjs), + abs(d__2)); + if (tjj > smlnum) { + +/* abs(A(j,j)) > SMLNUM: */ + + if (tjj < 1.) { + if (xj > tjj * bignum) { + +/* Scale X by 1/abs(x(j)). */ + + rec = 1. / xj; + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + xmax *= rec; + } + } + i__3 = j; + zladiv_(&z__1, &x[j], &tjjs); + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + } else if (tjj > 0.) { + +/* 0 < abs(A(j,j)) <= SMLNUM: */ + + if (xj > tjj * bignum) { + +/* Scale x by (1/abs(x(j)))*abs(A(j,j))*BIGNUM. */ + + rec = tjj * bignum / xj; + zdscal_(n, &rec, &x[1], &c__1); + *scale *= rec; + xmax *= rec; + } + i__3 = j; + zladiv_(&z__1, &x[j], &tjjs); + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + } else { + +/* A(j,j) = 0: Set x(1:n) = 0, x(j) = 1, and */ +/* scale = 0 and compute a solution to A**H *x = 0. */ + + i__3 = *n; + for (i__ = 1; i__ <= i__3; ++i__) { + i__4 = i__; + x[i__4].r = 0., x[i__4].i = 0.; +/* L200: */ + } + i__3 = j; + x[i__3].r = 1., x[i__3].i = 0.; + *scale = 0.; + xmax = 0.; + } +L210: + ; + } else { + +/* Compute x(j) := x(j) / A(j,j) - CSUMJ if the dot */ +/* product has already been divided by 1/A(j,j). */ + + i__3 = j; + zladiv_(&z__2, &x[j], &tjjs); + z__1.r = z__2.r - csumj.r, z__1.i = z__2.i - csumj.i; + x[i__3].r = z__1.r, x[i__3].i = z__1.i; + } +/* Computing MAX */ + i__3 = j; + d__3 = xmax, d__4 = (d__1 = x[i__3].r, abs(d__1)) + (d__2 = + d_imag(&x[j]), abs(d__2)); + xmax = max(d__3,d__4); +/* L220: */ + } + } + *scale /= tscal; + } + +/* Scale the column norms by 1/TSCAL for return. */ + + if (tscal != 1.) { + d__1 = 1. / tscal; + dscal_(n, &d__1, &cnorm[1], &c__1); + } + + return 0; + +/* End of ZLATRS */ + +} /* zlatrs_ */ |