294 lines
6.0 KiB
C
294 lines
6.0 KiB
C
/* drotmg.f -- translated by f2c (version 20100827).
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You must link the resulting object file with libf2c:
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on Microsoft Windows system, link with libf2c.lib;
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on Linux or Unix systems, link with .../path/to/libf2c.a -lm
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or, if you install libf2c.a in a standard place, with -lf2c -lm
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-- in that order, at the end of the command line, as in
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cc *.o -lf2c -lm
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
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http://www.netlib.org/f2c/libf2c.zip
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*/
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#include "datatypes.h"
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/* Subroutine */ int drotmg_(doublereal *dd1, doublereal *dd2, doublereal *
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dx1, doublereal *dy1, doublereal *dparam)
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{
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/* Initialized data */
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static doublereal zero = 0.;
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static doublereal one = 1.;
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static doublereal two = 2.;
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static doublereal gam = 4096.;
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static doublereal gamsq = 16777216.;
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static doublereal rgamsq = 5.9604645e-8;
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/* Format strings */
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static char fmt_120[] = "";
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static char fmt_150[] = "";
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static char fmt_180[] = "";
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static char fmt_210[] = "";
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/* System generated locals */
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doublereal d__1;
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/* Local variables */
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doublereal du, dp1, dp2, dq1, dq2, dh11, dh12, dh21, dh22;
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integer igo;
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doublereal dflag, dtemp;
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/* Assigned format variables */
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static char *igo_fmt;
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/* .. Scalar Arguments .. */
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/* .. */
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/* .. Array Arguments .. */
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/* .. */
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/* Purpose */
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/* ======= */
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/* CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS */
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/* THE SECOND COMPONENT OF THE 2-VECTOR (DSQRT(DD1)*DX1,DSQRT(DD2)* */
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/* DY2)**T. */
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/* WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS.. */
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/* DFLAG=-1.D0 DFLAG=0.D0 DFLAG=1.D0 DFLAG=-2.D0 */
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/* (DH11 DH12) (1.D0 DH12) (DH11 1.D0) (1.D0 0.D0) */
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/* H=( ) ( ) ( ) ( ) */
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/* (DH21 DH22), (DH21 1.D0), (-1.D0 DH22), (0.D0 1.D0). */
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/* LOCATIONS 2-4 OF DPARAM CONTAIN DH11, DH21, DH12, AND DH22 */
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/* RESPECTIVELY. (VALUES OF 1.D0, -1.D0, OR 0.D0 IMPLIED BY THE */
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/* VALUE OF DPARAM(1) ARE NOT STORED IN DPARAM.) */
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/* THE VALUES OF GAMSQ AND RGAMSQ SET IN THE DATA STATEMENT MAY BE */
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/* INEXACT. THIS IS OK AS THEY ARE ONLY USED FOR TESTING THE SIZE */
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/* OF DD1 AND DD2. ALL ACTUAL SCALING OF DATA IS DONE USING GAM. */
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/* Arguments */
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/* ========= */
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/* DD1 (input/output) DOUBLE PRECISION */
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/* DD2 (input/output) DOUBLE PRECISION */
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/* DX1 (input/output) DOUBLE PRECISION */
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/* DY1 (input) DOUBLE PRECISION */
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/* DPARAM (input/output) DOUBLE PRECISION array, dimension 5 */
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/* DPARAM(1)=DFLAG */
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/* DPARAM(2)=DH11 */
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/* DPARAM(3)=DH21 */
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/* DPARAM(4)=DH12 */
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/* DPARAM(5)=DH22 */
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/* ===================================================================== */
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/* .. Local Scalars .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. Data statements .. */
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/* Parameter adjustments */
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--dparam;
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/* Function Body */
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/* .. */
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if (! (*dd1 < zero)) {
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goto L10;
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}
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/* GO ZERO-H-D-AND-DX1.. */
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goto L60;
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L10:
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/* CASE-DD1-NONNEGATIVE */
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dp2 = *dd2 * *dy1;
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if (! (dp2 == zero)) {
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goto L20;
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}
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dflag = -two;
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goto L260;
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/* REGULAR-CASE.. */
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L20:
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dp1 = *dd1 * *dx1;
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dq2 = dp2 * *dy1;
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dq1 = dp1 * *dx1;
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if (! (abs(dq1) > abs(dq2))) {
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goto L40;
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}
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dh21 = -(*dy1) / *dx1;
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dh12 = dp2 / dp1;
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du = one - dh12 * dh21;
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if (! (du <= zero)) {
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goto L30;
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}
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/* GO ZERO-H-D-AND-DX1.. */
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goto L60;
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L30:
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dflag = zero;
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*dd1 /= du;
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*dd2 /= du;
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*dx1 *= du;
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/* GO SCALE-CHECK.. */
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goto L100;
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L40:
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if (! (dq2 < zero)) {
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goto L50;
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}
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/* GO ZERO-H-D-AND-DX1.. */
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goto L60;
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L50:
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dflag = one;
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dh11 = dp1 / dp2;
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dh22 = *dx1 / *dy1;
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du = one + dh11 * dh22;
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dtemp = *dd2 / du;
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*dd2 = *dd1 / du;
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*dd1 = dtemp;
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*dx1 = *dy1 * du;
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/* GO SCALE-CHECK */
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goto L100;
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/* PROCEDURE..ZERO-H-D-AND-DX1.. */
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L60:
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dflag = -one;
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dh11 = zero;
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dh12 = zero;
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dh21 = zero;
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dh22 = zero;
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*dd1 = zero;
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*dd2 = zero;
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*dx1 = zero;
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/* RETURN.. */
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goto L220;
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/* PROCEDURE..FIX-H.. */
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L70:
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if (! (dflag >= zero)) {
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goto L90;
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}
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if (! (dflag == zero)) {
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goto L80;
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}
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dh11 = one;
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dh22 = one;
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dflag = -one;
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goto L90;
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L80:
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dh21 = -one;
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dh12 = one;
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dflag = -one;
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L90:
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switch (igo) {
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case 0: goto L120;
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case 1: goto L150;
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case 2: goto L180;
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case 3: goto L210;
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}
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/* PROCEDURE..SCALE-CHECK */
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L100:
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L110:
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if (! (*dd1 <= rgamsq)) {
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goto L130;
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}
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if (*dd1 == zero) {
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goto L160;
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}
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igo = 0;
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igo_fmt = fmt_120;
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/* FIX-H.. */
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goto L70;
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L120:
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/* Computing 2nd power */
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d__1 = gam;
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*dd1 *= d__1 * d__1;
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*dx1 /= gam;
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dh11 /= gam;
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dh12 /= gam;
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goto L110;
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L130:
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L140:
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if (! (*dd1 >= gamsq)) {
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goto L160;
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}
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igo = 1;
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igo_fmt = fmt_150;
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/* FIX-H.. */
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goto L70;
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L150:
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/* Computing 2nd power */
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d__1 = gam;
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*dd1 /= d__1 * d__1;
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*dx1 *= gam;
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dh11 *= gam;
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dh12 *= gam;
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goto L140;
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L160:
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L170:
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if (! (abs(*dd2) <= rgamsq)) {
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goto L190;
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}
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if (*dd2 == zero) {
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goto L220;
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}
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igo = 2;
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igo_fmt = fmt_180;
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/* FIX-H.. */
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goto L70;
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L180:
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/* Computing 2nd power */
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d__1 = gam;
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*dd2 *= d__1 * d__1;
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dh21 /= gam;
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dh22 /= gam;
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goto L170;
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L190:
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L200:
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if (! (abs(*dd2) >= gamsq)) {
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goto L220;
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}
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igo = 3;
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igo_fmt = fmt_210;
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/* FIX-H.. */
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goto L70;
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L210:
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/* Computing 2nd power */
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d__1 = gam;
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*dd2 /= d__1 * d__1;
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dh21 *= gam;
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dh22 *= gam;
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goto L200;
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L220:
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if (dflag < 0.) {
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goto L250;
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} else if (dflag == 0) {
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goto L230;
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} else {
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goto L240;
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}
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L230:
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dparam[3] = dh21;
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dparam[4] = dh12;
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goto L260;
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L240:
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dparam[2] = dh11;
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dparam[5] = dh22;
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goto L260;
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L250:
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dparam[2] = dh11;
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dparam[3] = dh21;
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dparam[4] = dh12;
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dparam[5] = dh22;
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L260:
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dparam[1] = dflag;
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return 0;
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} /* drotmg_ */
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