/* ./src_f77/drotm.f -- translated by f2c (version 20030320).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include <punc/vf2c.h>

/* Subroutine */ int drotm_(integer *n, doublereal *dx, integer *incx, 
	doublereal *dy, integer *incy, doublereal *dparam)
{
    /* Initialized data */

    static doublereal zero = 0.;
    static doublereal two = 2.;

    /* System generated locals */
    integer i__1, i__2;

    /* Local variables */
    static integer i__;
    static doublereal w, z__;
    static integer kx, ky;
    static doublereal dh11, dh12, dh22, dh21, dflag;
    static integer nsteps;


/*     APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX */

/*     (DX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF DX ARE IN */
/*     (DY**T) */

/*     DX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE */
/*     LX = (-INCX)*N, AND SIMILARLY FOR SY USING LY AND INCY. */
/*     WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS.. */

/*     DFLAG=-1.D0     DFLAG=0.D0        DFLAG=1.D0     DFLAG=-2.D0 */

/*       (DH11  DH12)    (1.D0  DH12)    (DH11  1.D0)    (1.D0  0.D0) */
/*     H=(          )    (          )    (          )    (          ) */
/*       (DH21  DH22),   (DH21  1.D0),   (-1.D0 DH22),   (0.D0  1.D0). */
/*     SEE DROTMG FOR A DESCRIPTION OF DATA STORAGE IN DPARAM. */

    /* Parameter adjustments */
    --dparam;
    --dy;
    --dx;

    /* Function Body */

    dflag = dparam[1];
    if (*n <= 0 || dflag + two == zero) {
	goto L140;
    }
    if (! (*incx == *incy && *incx > 0)) {
	goto L70;
    }

    nsteps = *n * *incx;
    if (dflag < 0.) {
	goto L50;
    } else if (dflag == 0) {
	goto L10;
    } else {
	goto L30;
    }
L10:
    dh12 = dparam[4];
    dh21 = dparam[3];
    i__1 = nsteps;
    i__2 = *incx;
    for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
	w = dx[i__];
	z__ = dy[i__];
	dx[i__] = w + z__ * dh12;
	dy[i__] = w * dh21 + z__;
/* L20: */
    }
    goto L140;
L30:
    dh11 = dparam[2];
    dh22 = dparam[5];
    i__2 = nsteps;
    i__1 = *incx;
    for (i__ = 1; i__1 < 0 ? i__ >= i__2 : i__ <= i__2; i__ += i__1) {
	w = dx[i__];
	z__ = dy[i__];
	dx[i__] = w * dh11 + z__;
	dy[i__] = -w + dh22 * z__;
/* L40: */
    }
    goto L140;
L50:
    dh11 = dparam[2];
    dh12 = dparam[4];
    dh21 = dparam[3];
    dh22 = dparam[5];
    i__1 = nsteps;
    i__2 = *incx;
    for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
	w = dx[i__];
	z__ = dy[i__];
	dx[i__] = w * dh11 + z__ * dh12;
	dy[i__] = w * dh21 + z__ * dh22;
/* L60: */
    }
    goto L140;
L70:
    kx = 1;
    ky = 1;
    if (*incx < 0) {
	kx = (1 - *n) * *incx + 1;
    }
    if (*incy < 0) {
	ky = (1 - *n) * *incy + 1;
    }

    if (dflag < 0.) {
	goto L120;
    } else if (dflag == 0) {
	goto L80;
    } else {
	goto L100;
    }
L80:
    dh12 = dparam[4];
    dh21 = dparam[3];
    i__2 = *n;
    for (i__ = 1; i__ <= i__2; ++i__) {
	w = dx[kx];
	z__ = dy[ky];
	dx[kx] = w + z__ * dh12;
	dy[ky] = w * dh21 + z__;
	kx += *incx;
	ky += *incy;
/* L90: */
    }
    goto L140;
L100:
    dh11 = dparam[2];
    dh22 = dparam[5];
    i__2 = *n;
    for (i__ = 1; i__ <= i__2; ++i__) {
	w = dx[kx];
	z__ = dy[ky];
	dx[kx] = w * dh11 + z__;
	dy[ky] = -w + dh22 * z__;
	kx += *incx;
	ky += *incy;
/* L110: */
    }
    goto L140;
L120:
    dh11 = dparam[2];
    dh12 = dparam[4];
    dh21 = dparam[3];
    dh22 = dparam[5];
    i__2 = *n;
    for (i__ = 1; i__ <= i__2; ++i__) {
	w = dx[kx];
	z__ = dy[ky];
	dx[kx] = w * dh11 + z__ * dh12;
	dy[ky] = w * dh21 + z__ * dh22;
	kx += *incx;
	ky += *incy;
/* L130: */
    }
L140:
    return 0;
} /* drotm_ */

