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authorshmel1k <shmel1k@ydb.tech>2022-09-02 12:44:59 +0300
committershmel1k <shmel1k@ydb.tech>2022-09-02 12:44:59 +0300
commit90d450f74722da7859d6f510a869f6c6908fd12f (patch)
tree538c718dedc76cdfe37ad6d01ff250dd930d9278 /contrib/libs/clapack/dlag2.c
parent01f64c1ecd0d4ffa9e3a74478335f1745f26cc75 (diff)
downloadydb-90d450f74722da7859d6f510a869f6c6908fd12f.tar.gz
[] add metering mode to CLI
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+/* dlag2.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"
+
+/* Subroutine */ int dlag2_(doublereal *a, integer *lda, doublereal *b,
+ integer *ldb, doublereal *safmin, doublereal *scale1, doublereal *
+ scale2, doublereal *wr1, doublereal *wr2, doublereal *wi)
+{
+ /* System generated locals */
+ integer a_dim1, a_offset, b_dim1, b_offset;
+ doublereal d__1, d__2, d__3, d__4, d__5, d__6;
+
+ /* Builtin functions */
+ double sqrt(doublereal), d_sign(doublereal *, doublereal *);
+
+ /* Local variables */
+ doublereal r__, c1, c2, c3, c4, c5, s1, s2, a11, a12, a21, a22, b11, b12,
+ b22, pp, qq, ss, as11, as12, as22, sum, abi22, diff, bmin, wbig,
+ wabs, wdet, binv11, binv22, discr, anorm, bnorm, bsize, shift,
+ rtmin, rtmax, wsize, ascale, bscale, wscale, safmax, wsmall;
+
+
+/* -- LAPACK auxiliary routine (version 3.2) -- */
+/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/* November 2006 */
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* DLAG2 computes the eigenvalues of a 2 x 2 generalized eigenvalue */
+/* problem A - w B, with scaling as necessary to avoid over-/underflow. */
+
+/* The scaling factor "s" results in a modified eigenvalue equation */
+
+/* s A - w B */
+
+/* where s is a non-negative scaling factor chosen so that w, w B, */
+/* and s A do not overflow and, if possible, do not underflow, either. */
+
+/* Arguments */
+/* ========= */
+
+/* A (input) DOUBLE PRECISION array, dimension (LDA, 2) */
+/* On entry, the 2 x 2 matrix A. It is assumed that its 1-norm */
+/* is less than 1/SAFMIN. Entries less than */
+/* sqrt(SAFMIN)*norm(A) are subject to being treated as zero. */
+
+/* LDA (input) INTEGER */
+/* The leading dimension of the array A. LDA >= 2. */
+
+/* B (input) DOUBLE PRECISION array, dimension (LDB, 2) */
+/* On entry, the 2 x 2 upper triangular matrix B. It is */
+/* assumed that the one-norm of B is less than 1/SAFMIN. The */
+/* diagonals should be at least sqrt(SAFMIN) times the largest */
+/* element of B (in absolute value); if a diagonal is smaller */
+/* than that, then +/- sqrt(SAFMIN) will be used instead of */
+/* that diagonal. */
+
+/* LDB (input) INTEGER */
+/* The leading dimension of the array B. LDB >= 2. */
+
+/* SAFMIN (input) DOUBLE PRECISION */
+/* The smallest positive number s.t. 1/SAFMIN does not */
+/* overflow. (This should always be DLAMCH('S') -- it is an */
+/* argument in order to avoid having to call DLAMCH frequently.) */
+
+/* SCALE1 (output) DOUBLE PRECISION */
+/* A scaling factor used to avoid over-/underflow in the */
+/* eigenvalue equation which defines the first eigenvalue. If */
+/* the eigenvalues are complex, then the eigenvalues are */
+/* ( WR1 +/- WI i ) / SCALE1 (which may lie outside the */
+/* exponent range of the machine), SCALE1=SCALE2, and SCALE1 */
+/* will always be positive. If the eigenvalues are real, then */
+/* the first (real) eigenvalue is WR1 / SCALE1 , but this may */
+/* overflow or underflow, and in fact, SCALE1 may be zero or */
+/* less than the underflow threshhold if the exact eigenvalue */
+/* is sufficiently large. */
+
+/* SCALE2 (output) DOUBLE PRECISION */
+/* A scaling factor used to avoid over-/underflow in the */
+/* eigenvalue equation which defines the second eigenvalue. If */
+/* the eigenvalues are complex, then SCALE2=SCALE1. If the */
+/* eigenvalues are real, then the second (real) eigenvalue is */
+/* WR2 / SCALE2 , but this may overflow or underflow, and in */
+/* fact, SCALE2 may be zero or less than the underflow */
+/* threshhold if the exact eigenvalue is sufficiently large. */
+
+/* WR1 (output) DOUBLE PRECISION */
+/* If the eigenvalue is real, then WR1 is SCALE1 times the */
+/* eigenvalue closest to the (2,2) element of A B**(-1). If the */
+/* eigenvalue is complex, then WR1=WR2 is SCALE1 times the real */
+/* part of the eigenvalues. */
+
+/* WR2 (output) DOUBLE PRECISION */
+/* If the eigenvalue is real, then WR2 is SCALE2 times the */
+/* other eigenvalue. If the eigenvalue is complex, then */
+/* WR1=WR2 is SCALE1 times the real part of the eigenvalues. */
+
+/* WI (output) DOUBLE PRECISION */
+/* If the eigenvalue is real, then WI is zero. If the */
+/* eigenvalue is complex, then WI is SCALE1 times the imaginary */
+/* part of the eigenvalues. WI will always be non-negative. */
+
+/* ===================================================================== */
+
+/* .. Parameters .. */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+/* .. Executable Statements .. */
+
+ /* Parameter adjustments */
+ a_dim1 = *lda;
+ a_offset = 1 + a_dim1;
+ a -= a_offset;
+ b_dim1 = *ldb;
+ b_offset = 1 + b_dim1;
+ b -= b_offset;
+
+ /* Function Body */
+ rtmin = sqrt(*safmin);
+ rtmax = 1. / rtmin;
+ safmax = 1. / *safmin;
+
+/* Scale A */
+
+/* Computing MAX */
+ d__5 = (d__1 = a[a_dim1 + 1], abs(d__1)) + (d__2 = a[a_dim1 + 2], abs(
+ d__2)), d__6 = (d__3 = a[(a_dim1 << 1) + 1], abs(d__3)) + (d__4 =
+ a[(a_dim1 << 1) + 2], abs(d__4)), d__5 = max(d__5,d__6);
+ anorm = max(d__5,*safmin);
+ ascale = 1. / anorm;
+ a11 = ascale * a[a_dim1 + 1];
+ a21 = ascale * a[a_dim1 + 2];
+ a12 = ascale * a[(a_dim1 << 1) + 1];
+ a22 = ascale * a[(a_dim1 << 1) + 2];
+
+/* Perturb B if necessary to insure non-singularity */
+
+ b11 = b[b_dim1 + 1];
+ b12 = b[(b_dim1 << 1) + 1];
+ b22 = b[(b_dim1 << 1) + 2];
+/* Computing MAX */
+ d__1 = abs(b11), d__2 = abs(b12), d__1 = max(d__1,d__2), d__2 = abs(b22),
+ d__1 = max(d__1,d__2);
+ bmin = rtmin * max(d__1,rtmin);
+ if (abs(b11) < bmin) {
+ b11 = d_sign(&bmin, &b11);
+ }
+ if (abs(b22) < bmin) {
+ b22 = d_sign(&bmin, &b22);
+ }
+
+/* Scale B */
+
+/* Computing MAX */
+ d__1 = abs(b11), d__2 = abs(b12) + abs(b22), d__1 = max(d__1,d__2);
+ bnorm = max(d__1,*safmin);
+/* Computing MAX */
+ d__1 = abs(b11), d__2 = abs(b22);
+ bsize = max(d__1,d__2);
+ bscale = 1. / bsize;
+ b11 *= bscale;
+ b12 *= bscale;
+ b22 *= bscale;
+
+/* Compute larger eigenvalue by method described by C. van Loan */
+
+/* ( AS is A shifted by -SHIFT*B ) */
+
+ binv11 = 1. / b11;
+ binv22 = 1. / b22;
+ s1 = a11 * binv11;
+ s2 = a22 * binv22;
+ if (abs(s1) <= abs(s2)) {
+ as12 = a12 - s1 * b12;
+ as22 = a22 - s1 * b22;
+ ss = a21 * (binv11 * binv22);
+ abi22 = as22 * binv22 - ss * b12;
+ pp = abi22 * .5;
+ shift = s1;
+ } else {
+ as12 = a12 - s2 * b12;
+ as11 = a11 - s2 * b11;
+ ss = a21 * (binv11 * binv22);
+ abi22 = -ss * b12;
+ pp = (as11 * binv11 + abi22) * .5;
+ shift = s2;
+ }
+ qq = ss * as12;
+ if ((d__1 = pp * rtmin, abs(d__1)) >= 1.) {
+/* Computing 2nd power */
+ d__1 = rtmin * pp;
+ discr = d__1 * d__1 + qq * *safmin;
+ r__ = sqrt((abs(discr))) * rtmax;
+ } else {
+/* Computing 2nd power */
+ d__1 = pp;
+ if (d__1 * d__1 + abs(qq) <= *safmin) {
+/* Computing 2nd power */
+ d__1 = rtmax * pp;
+ discr = d__1 * d__1 + qq * safmax;
+ r__ = sqrt((abs(discr))) * rtmin;
+ } else {
+/* Computing 2nd power */
+ d__1 = pp;
+ discr = d__1 * d__1 + qq;
+ r__ = sqrt((abs(discr)));
+ }
+ }
+
+/* Note: the test of R in the following IF is to cover the case when */
+/* DISCR is small and negative and is flushed to zero during */
+/* the calculation of R. On machines which have a consistent */
+/* flush-to-zero threshhold and handle numbers above that */
+/* threshhold correctly, it would not be necessary. */
+
+ if (discr >= 0. || r__ == 0.) {
+ sum = pp + d_sign(&r__, &pp);
+ diff = pp - d_sign(&r__, &pp);
+ wbig = shift + sum;
+
+/* Compute smaller eigenvalue */
+
+ wsmall = shift + diff;
+/* Computing MAX */
+ d__1 = abs(wsmall);
+ if (abs(wbig) * .5 > max(d__1,*safmin)) {
+ wdet = (a11 * a22 - a12 * a21) * (binv11 * binv22);
+ wsmall = wdet / wbig;
+ }
+
+/* Choose (real) eigenvalue closest to 2,2 element of A*B**(-1) */
+/* for WR1. */
+
+ if (pp > abi22) {
+ *wr1 = min(wbig,wsmall);
+ *wr2 = max(wbig,wsmall);
+ } else {
+ *wr1 = max(wbig,wsmall);
+ *wr2 = min(wbig,wsmall);
+ }
+ *wi = 0.;
+ } else {
+
+/* Complex eigenvalues */
+
+ *wr1 = shift + pp;
+ *wr2 = *wr1;
+ *wi = r__;
+ }
+
+/* Further scaling to avoid underflow and overflow in computing */
+/* SCALE1 and overflow in computing w*B. */
+
+/* This scale factor (WSCALE) is bounded from above using C1 and C2, */
+/* and from below using C3 and C4. */
+/* C1 implements the condition s A must never overflow. */
+/* C2 implements the condition w B must never overflow. */
+/* C3, with C2, */
+/* implement the condition that s A - w B must never overflow. */
+/* C4 implements the condition s should not underflow. */
+/* C5 implements the condition max(s,|w|) should be at least 2. */
+
+ c1 = bsize * (*safmin * max(1.,ascale));
+ c2 = *safmin * max(1.,bnorm);
+ c3 = bsize * *safmin;
+ if (ascale <= 1. && bsize <= 1.) {
+/* Computing MIN */
+ d__1 = 1., d__2 = ascale / *safmin * bsize;
+ c4 = min(d__1,d__2);
+ } else {
+ c4 = 1.;
+ }
+ if (ascale <= 1. || bsize <= 1.) {
+/* Computing MIN */
+ d__1 = 1., d__2 = ascale * bsize;
+ c5 = min(d__1,d__2);
+ } else {
+ c5 = 1.;
+ }
+
+/* Scale first eigenvalue */
+
+ wabs = abs(*wr1) + abs(*wi);
+/* Computing MAX */
+/* Computing MIN */
+ d__3 = c4, d__4 = max(wabs,c5) * .5;
+ d__1 = max(*safmin,c1), d__2 = (wabs * c2 + c3) * 1.0000100000000001,
+ d__1 = max(d__1,d__2), d__2 = min(d__3,d__4);
+ wsize = max(d__1,d__2);
+ if (wsize != 1.) {
+ wscale = 1. / wsize;
+ if (wsize > 1.) {
+ *scale1 = max(ascale,bsize) * wscale * min(ascale,bsize);
+ } else {
+ *scale1 = min(ascale,bsize) * wscale * max(ascale,bsize);
+ }
+ *wr1 *= wscale;
+ if (*wi != 0.) {
+ *wi *= wscale;
+ *wr2 = *wr1;
+ *scale2 = *scale1;
+ }
+ } else {
+ *scale1 = ascale * bsize;
+ *scale2 = *scale1;
+ }
+
+/* Scale second eigenvalue (if real) */
+
+ if (*wi == 0.) {
+/* Computing MAX */
+/* Computing MIN */
+/* Computing MAX */
+ d__5 = abs(*wr2);
+ d__3 = c4, d__4 = max(d__5,c5) * .5;
+ d__1 = max(*safmin,c1), d__2 = (abs(*wr2) * c2 + c3) *
+ 1.0000100000000001, d__1 = max(d__1,d__2), d__2 = min(d__3,
+ d__4);
+ wsize = max(d__1,d__2);
+ if (wsize != 1.) {
+ wscale = 1. / wsize;
+ if (wsize > 1.) {
+ *scale2 = max(ascale,bsize) * wscale * min(ascale,bsize);
+ } else {
+ *scale2 = min(ascale,bsize) * wscale * max(ascale,bsize);
+ }
+ *wr2 *= wscale;
+ } else {
+ *scale2 = ascale * bsize;
+ }
+ }
+
+/* End of DLAG2 */
+
+ return 0;
+} /* dlag2_ */