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/* clargv.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 clargv_(integer *n, complex *x, integer *incx, complex *
y, integer *incy, real *c__, integer *incc)
{
/* System generated locals */
integer i__1, i__2;
real r__1, r__2, r__3, r__4, r__5, r__6, r__7, r__8, r__9, r__10;
complex q__1, q__2, q__3;
/* Builtin functions */
double log(doublereal), pow_ri(real *, integer *), r_imag(complex *),
sqrt(doublereal);
void r_cnjg(complex *, complex *);
/* Local variables */
real d__;
complex f, g;
integer i__, j;
complex r__;
real f2, g2;
integer ic;
real di;
complex ff;
real cs, dr;
complex fs, gs;
integer ix, iy;
complex sn;
real f2s, g2s, eps, scale;
integer count;
real safmn2, safmx2;
extern doublereal slapy2_(real *, real *), slamch_(char *);
real safmin;
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CLARGV generates a vector of complex plane rotations with real */
/* cosines, determined by elements of the complex vectors x and y. */
/* For i = 1,2,...,n */
/* ( c(i) s(i) ) ( x(i) ) = ( r(i) ) */
/* ( -conjg(s(i)) c(i) ) ( y(i) ) = ( 0 ) */
/* where c(i)**2 + ABS(s(i))**2 = 1 */
/* The following conventions are used (these are the same as in CLARTG, */
/* but differ from the BLAS1 routine CROTG): */
/* If y(i)=0, then c(i)=1 and s(i)=0. */
/* If x(i)=0, then c(i)=0 and s(i) is chosen so that r(i) is real. */
/* Arguments */
/* ========= */
/* N (input) INTEGER */
/* The number of plane rotations to be generated. */
/* X (input/output) COMPLEX array, dimension (1+(N-1)*INCX) */
/* On entry, the vector x. */
/* On exit, x(i) is overwritten by r(i), for i = 1,...,n. */
/* INCX (input) INTEGER */
/* The increment between elements of X. INCX > 0. */
/* Y (input/output) COMPLEX array, dimension (1+(N-1)*INCY) */
/* On entry, the vector y. */
/* On exit, the sines of the plane rotations. */
/* INCY (input) INTEGER */
/* The increment between elements of Y. INCY > 0. */
/* C (output) REAL array, dimension (1+(N-1)*INCC) */
/* The cosines of the plane rotations. */
/* INCC (input) INTEGER */
/* The increment between elements of C. INCC > 0. */
/* Further Details */
/* ======= ======= */
/* 6-6-96 - Modified with a new algorithm by W. Kahan and J. Demmel */
/* This version has a few statements commented out for thread safety */
/* (machine parameters are computed on each entry). 10 feb 03, SJH. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* LOGICAL FIRST */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Statement Functions .. */
/* .. */
/* .. Save statement .. */
/* SAVE FIRST, SAFMX2, SAFMIN, SAFMN2 */
/* .. */
/* .. Data statements .. */
/* DATA FIRST / .TRUE. / */
/* .. */
/* .. Statement Function definitions .. */
/* .. */
/* .. Executable Statements .. */
/* IF( FIRST ) THEN */
/* FIRST = .FALSE. */
/* Parameter adjustments */
--c__;
--y;
--x;
/* Function Body */
safmin = slamch_("S");
eps = slamch_("E");
r__1 = slamch_("B");
i__1 = (integer) (log(safmin / eps) / log(slamch_("B")) / 2.f);
safmn2 = pow_ri(&r__1, &i__1);
safmx2 = 1.f / safmn2;
/* END IF */
ix = 1;
iy = 1;
ic = 1;
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
i__2 = ix;
f.r = x[i__2].r, f.i = x[i__2].i;
i__2 = iy;
g.r = y[i__2].r, g.i = y[i__2].i;
/* Use identical algorithm as in CLARTG */
/* Computing MAX */
/* Computing MAX */
r__7 = (r__1 = f.r, dabs(r__1)), r__8 = (r__2 = r_imag(&f), dabs(r__2)
);
/* Computing MAX */
r__9 = (r__3 = g.r, dabs(r__3)), r__10 = (r__4 = r_imag(&g), dabs(
r__4));
r__5 = dmax(r__7,r__8), r__6 = dmax(r__9,r__10);
scale = dmax(r__5,r__6);
fs.r = f.r, fs.i = f.i;
gs.r = g.r, gs.i = g.i;
count = 0;
if (scale >= safmx2) {
L10:
++count;
q__1.r = safmn2 * fs.r, q__1.i = safmn2 * fs.i;
fs.r = q__1.r, fs.i = q__1.i;
q__1.r = safmn2 * gs.r, q__1.i = safmn2 * gs.i;
gs.r = q__1.r, gs.i = q__1.i;
scale *= safmn2;
if (scale >= safmx2) {
goto L10;
}
} else if (scale <= safmn2) {
if (g.r == 0.f && g.i == 0.f) {
cs = 1.f;
sn.r = 0.f, sn.i = 0.f;
r__.r = f.r, r__.i = f.i;
goto L50;
}
L20:
--count;
q__1.r = safmx2 * fs.r, q__1.i = safmx2 * fs.i;
fs.r = q__1.r, fs.i = q__1.i;
q__1.r = safmx2 * gs.r, q__1.i = safmx2 * gs.i;
gs.r = q__1.r, gs.i = q__1.i;
scale *= safmx2;
if (scale <= safmn2) {
goto L20;
}
}
/* Computing 2nd power */
r__1 = fs.r;
/* Computing 2nd power */
r__2 = r_imag(&fs);
f2 = r__1 * r__1 + r__2 * r__2;
/* Computing 2nd power */
r__1 = gs.r;
/* Computing 2nd power */
r__2 = r_imag(&gs);
g2 = r__1 * r__1 + r__2 * r__2;
if (f2 <= dmax(g2,1.f) * safmin) {
/* This is a rare case: F is very small. */
if (f.r == 0.f && f.i == 0.f) {
cs = 0.f;
r__2 = g.r;
r__3 = r_imag(&g);
r__1 = slapy2_(&r__2, &r__3);
r__.r = r__1, r__.i = 0.f;
/* Do complex/real division explicitly with two real */
/* divisions */
r__1 = gs.r;
r__2 = r_imag(&gs);
d__ = slapy2_(&r__1, &r__2);
r__1 = gs.r / d__;
r__2 = -r_imag(&gs) / d__;
q__1.r = r__1, q__1.i = r__2;
sn.r = q__1.r, sn.i = q__1.i;
goto L50;
}
r__1 = fs.r;
r__2 = r_imag(&fs);
f2s = slapy2_(&r__1, &r__2);
/* G2 and G2S are accurate */
/* G2 is at least SAFMIN, and G2S is at least SAFMN2 */
g2s = sqrt(g2);
/* Error in CS from underflow in F2S is at most */
/* UNFL / SAFMN2 .lt. sqrt(UNFL*EPS) .lt. EPS */
/* If MAX(G2,ONE)=G2, then F2 .lt. G2*SAFMIN, */
/* and so CS .lt. sqrt(SAFMIN) */
/* If MAX(G2,ONE)=ONE, then F2 .lt. SAFMIN */
/* and so CS .lt. sqrt(SAFMIN)/SAFMN2 = sqrt(EPS) */
/* Therefore, CS = F2S/G2S / sqrt( 1 + (F2S/G2S)**2 ) = F2S/G2S */
cs = f2s / g2s;
/* Make sure abs(FF) = 1 */
/* Do complex/real division explicitly with 2 real divisions */
/* Computing MAX */
r__3 = (r__1 = f.r, dabs(r__1)), r__4 = (r__2 = r_imag(&f), dabs(
r__2));
if (dmax(r__3,r__4) > 1.f) {
r__1 = f.r;
r__2 = r_imag(&f);
d__ = slapy2_(&r__1, &r__2);
r__1 = f.r / d__;
r__2 = r_imag(&f) / d__;
q__1.r = r__1, q__1.i = r__2;
ff.r = q__1.r, ff.i = q__1.i;
} else {
dr = safmx2 * f.r;
di = safmx2 * r_imag(&f);
d__ = slapy2_(&dr, &di);
r__1 = dr / d__;
r__2 = di / d__;
q__1.r = r__1, q__1.i = r__2;
ff.r = q__1.r, ff.i = q__1.i;
}
r__1 = gs.r / g2s;
r__2 = -r_imag(&gs) / g2s;
q__2.r = r__1, q__2.i = r__2;
q__1.r = ff.r * q__2.r - ff.i * q__2.i, q__1.i = ff.r * q__2.i +
ff.i * q__2.r;
sn.r = q__1.r, sn.i = q__1.i;
q__2.r = cs * f.r, q__2.i = cs * f.i;
q__3.r = sn.r * g.r - sn.i * g.i, q__3.i = sn.r * g.i + sn.i *
g.r;
q__1.r = q__2.r + q__3.r, q__1.i = q__2.i + q__3.i;
r__.r = q__1.r, r__.i = q__1.i;
} else {
/* This is the most common case. */
/* Neither F2 nor F2/G2 are less than SAFMIN */
/* F2S cannot overflow, and it is accurate */
f2s = sqrt(g2 / f2 + 1.f);
/* Do the F2S(real)*FS(complex) multiply with two real */
/* multiplies */
r__1 = f2s * fs.r;
r__2 = f2s * r_imag(&fs);
q__1.r = r__1, q__1.i = r__2;
r__.r = q__1.r, r__.i = q__1.i;
cs = 1.f / f2s;
d__ = f2 + g2;
/* Do complex/real division explicitly with two real divisions */
r__1 = r__.r / d__;
r__2 = r_imag(&r__) / d__;
q__1.r = r__1, q__1.i = r__2;
sn.r = q__1.r, sn.i = q__1.i;
r_cnjg(&q__2, &gs);
q__1.r = sn.r * q__2.r - sn.i * q__2.i, q__1.i = sn.r * q__2.i +
sn.i * q__2.r;
sn.r = q__1.r, sn.i = q__1.i;
if (count != 0) {
if (count > 0) {
i__2 = count;
for (j = 1; j <= i__2; ++j) {
q__1.r = safmx2 * r__.r, q__1.i = safmx2 * r__.i;
r__.r = q__1.r, r__.i = q__1.i;
/* L30: */
}
} else {
i__2 = -count;
for (j = 1; j <= i__2; ++j) {
q__1.r = safmn2 * r__.r, q__1.i = safmn2 * r__.i;
r__.r = q__1.r, r__.i = q__1.i;
/* L40: */
}
}
}
}
L50:
c__[ic] = cs;
i__2 = iy;
y[i__2].r = sn.r, y[i__2].i = sn.i;
i__2 = ix;
x[i__2].r = r__.r, x[i__2].i = r__.i;
ic += *incc;
iy += *incy;
ix += *incx;
/* L60: */
}
return 0;
/* End of CLARGV */
} /* clargv_ */
|
