clar2v.c

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/* clar2v.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 clar2v_(integer *n, complex *x, complex *y, complex *z__, 
         integer *incx, real *c__, complex *s, integer *incc)
{
    /* System generated locals */
    integer i__1, i__2;
    real r__1;
    complex q__1, q__2, q__3, q__4, q__5;

    /* Builtin functions */
    double r_imag(complex *);
    void r_cnjg(complex *, complex *);

    /* Local variables */
    integer i__;
    complex t2, t3, t4;
    real t5, t6;
    integer ic;
    real ci;
    complex si;
    integer ix;
    real xi, yi;
    complex zi;
    real t1i, t1r, sii, zii, sir, zir;


/*  -- LAPACK auxiliary routine (version 3.2) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  CLAR2V applies a vector of complex plane rotations with real cosines */
/*  from both sides to a sequence of 2-by-2 complex Hermitian matrices, */
/*  defined by the elements of the vectors x, y and z. For i = 1,2,...,n */

/*     (       x(i)  z(i) ) := */
/*     ( conjg(z(i)) y(i) ) */

/*       (  c(i) conjg(s(i)) ) (       x(i)  z(i) ) ( c(i) -conjg(s(i)) ) */
/*       ( -s(i)       c(i)  ) ( conjg(z(i)) y(i) ) ( s(i)        c(i)  ) */

/*  Arguments */
/*  ========= */

/*  N       (input) INTEGER */
/*          The number of plane rotations to be applied. */

/*  X       (input/output) COMPLEX array, dimension (1+(N-1)*INCX) */
/*          The vector x; the elements of x are assumed to be real. */

/*  Y       (input/output) COMPLEX array, dimension (1+(N-1)*INCX) */
/*          The vector y; the elements of y are assumed to be real. */

/*  Z       (input/output) COMPLEX array, dimension (1+(N-1)*INCX) */
/*          The vector z. */

/*  INCX    (input) INTEGER */
/*          The increment between elements of X, Y and Z. INCX > 0. */

/*  C       (input) REAL array, dimension (1+(N-1)*INCC) */
/*          The cosines of the plane rotations. */

/*  S       (input) COMPLEX array, dimension (1+(N-1)*INCC) */
/*          The sines of the plane rotations. */

/*  INCC    (input) INTEGER */
/*          The increment between elements of C and S. INCC > 0. */

/*  ===================================================================== */

/*     .. Local Scalars .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Executable Statements .. */

    /* Parameter adjustments */
    --s;
    --c__;
    --z__;
    --y;
    --x;

    /* Function Body */
    ix = 1;
    ic = 1;
    i__1 = *n;
    for (i__ = 1; i__ <= i__1; ++i__) {
        i__2 = ix;
        xi = x[i__2].r;
        i__2 = ix;
        yi = y[i__2].r;
        i__2 = ix;
        zi.r = z__[i__2].r, zi.i = z__[i__2].i;
        zir = zi.r;
        zii = r_imag(&zi);
        ci = c__[ic];
        i__2 = ic;
        si.r = s[i__2].r, si.i = s[i__2].i;
        sir = si.r;
        sii = r_imag(&si);
        t1r = sir * zir - sii * zii;
        t1i = sir * zii + sii * zir;
        q__1.r = ci * zi.r, q__1.i = ci * zi.i;
        t2.r = q__1.r, t2.i = q__1.i;
        r_cnjg(&q__3, &si);
        q__2.r = xi * q__3.r, q__2.i = xi * q__3.i;
        q__1.r = t2.r - q__2.r, q__1.i = t2.i - q__2.i;
        t3.r = q__1.r, t3.i = q__1.i;
        r_cnjg(&q__2, &t2);
        q__3.r = yi * si.r, q__3.i = yi * si.i;
        q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
        t4.r = q__1.r, t4.i = q__1.i;
        t5 = ci * xi + t1r;
        t6 = ci * yi - t1r;
        i__2 = ix;
        r__1 = ci * t5 + (sir * t4.r + sii * r_imag(&t4));
        x[i__2].r = r__1, x[i__2].i = 0.f;
        i__2 = ix;
        r__1 = ci * t6 - (sir * t3.r - sii * r_imag(&t3));
        y[i__2].r = r__1, y[i__2].i = 0.f;
        i__2 = ix;
        q__2.r = ci * t3.r, q__2.i = ci * t3.i;
        r_cnjg(&q__4, &si);
        q__5.r = t6, q__5.i = t1i;
        q__3.r = q__4.r * q__5.r - q__4.i * q__5.i, q__3.i = q__4.r * q__5.i 
                + q__4.i * q__5.r;
        q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
        z__[i__2].r = q__1.r, z__[i__2].i = q__1.i;
        ix += *incx;
        ic += *incc;
/* L10: */
    }
    return 0;

/*     End of CLAR2V */

} /* clar2v_ */