#include "blaswrap.h" /* zlargv.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" /* Subroutine */ int zlargv_(integer *n, doublecomplex *x, integer *incx, doublecomplex *y, integer *incy, doublereal *c__, integer *incc) { /* System generated locals */ integer i__1, i__2; doublereal d__1, d__2, d__3, d__4, d__5, d__6, d__7, d__8, d__9, d__10; doublecomplex z__1, z__2, z__3; /* Builtin functions */ double log(doublereal), pow_di(doublereal *, integer *), d_imag( doublecomplex *), sqrt(doublereal); void d_cnjg(doublecomplex *, doublecomplex *); /* Local variables */ static doublereal d__; static doublecomplex f, g; static integer i__, j; static doublecomplex r__; static doublereal f2, g2; static integer ic; static doublereal di; static doublecomplex ff; static doublereal cs, dr; static doublecomplex fs, gs; static integer ix, iy; static doublecomplex sn; static doublereal f2s, g2s, eps, scale; static integer count; static doublereal safmn2; extern doublereal dlapy2_(doublereal *, doublereal *); static doublereal safmx2; extern doublereal dlamch_(char *); static doublereal safmin; /* -- LAPACK auxiliary routine (version 3.1) -- Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. November 2006 Purpose ======= ZLARGV 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 ZLARTG, but differ from the BLAS1 routine ZROTG): 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*16 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*16 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) DOUBLE PRECISION 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. ===================================================================== LOGICAL FIRST SAVE FIRST, SAFMX2, SAFMIN, SAFMN2 DATA FIRST / .TRUE. / IF( FIRST ) THEN FIRST = .FALSE. Parameter adjustments */ --c__; --y; --x; /* Function Body */ safmin = dlamch_("S"); eps = dlamch_("E"); d__1 = dlamch_("B"); i__1 = (integer) (log(safmin / eps) / log(dlamch_("B")) / 2.); safmn2 = pow_di(&d__1, &i__1); safmx2 = 1. / 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 ZLARTG Computing MAX Computing MAX */ d__7 = (d__1 = f.r, abs(d__1)), d__8 = (d__2 = d_imag(&f), abs(d__2)); /* Computing MAX */ d__9 = (d__3 = g.r, abs(d__3)), d__10 = (d__4 = d_imag(&g), abs(d__4)) ; d__5 = max(d__7,d__8), d__6 = max(d__9,d__10); scale = max(d__5,d__6); fs.r = f.r, fs.i = f.i; gs.r = g.r, gs.i = g.i; count = 0; if (scale >= safmx2) { L10: ++count; z__1.r = safmn2 * fs.r, z__1.i = safmn2 * fs.i; fs.r = z__1.r, fs.i = z__1.i; z__1.r = safmn2 * gs.r, z__1.i = safmn2 * gs.i; gs.r = z__1.r, gs.i = z__1.i; scale *= safmn2; if (scale >= safmx2) { goto L10; } } else if (scale <= safmn2) { if (g.r == 0. && g.i == 0.) { cs = 1.; sn.r = 0., sn.i = 0.; r__.r = f.r, r__.i = f.i; goto L50; } L20: --count; z__1.r = safmx2 * fs.r, z__1.i = safmx2 * fs.i; fs.r = z__1.r, fs.i = z__1.i; z__1.r = safmx2 * gs.r, z__1.i = safmx2 * gs.i; gs.r = z__1.r, gs.i = z__1.i; scale *= safmx2; if (scale <= safmn2) { goto L20; } } /* Computing 2nd power */ d__1 = fs.r; /* Computing 2nd power */ d__2 = d_imag(&fs); f2 = d__1 * d__1 + d__2 * d__2; /* Computing 2nd power */ d__1 = gs.r; /* Computing 2nd power */ d__2 = d_imag(&gs); g2 = d__1 * d__1 + d__2 * d__2; if (f2 <= max(g2,1.) * safmin) { /* This is a rare case: F is very small. */ if (f.r == 0. && f.i == 0.) { cs = 0.; d__2 = g.r; d__3 = d_imag(&g); d__1 = dlapy2_(&d__2, &d__3); r__.r = d__1, r__.i = 0.; /* Do complex/real division explicitly with two real divisions */ d__1 = gs.r; d__2 = d_imag(&gs); d__ = dlapy2_(&d__1, &d__2); d__1 = gs.r / d__; d__2 = -d_imag(&gs) / d__; z__1.r = d__1, z__1.i = d__2; sn.r = z__1.r, sn.i = z__1.i; goto L50; } d__1 = fs.r; d__2 = d_imag(&fs); f2s = dlapy2_(&d__1, &d__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 */ d__3 = (d__1 = f.r, abs(d__1)), d__4 = (d__2 = d_imag(&f), abs( d__2)); if (max(d__3,d__4) > 1.) { d__1 = f.r; d__2 = d_imag(&f); d__ = dlapy2_(&d__1, &d__2); d__1 = f.r / d__; d__2 = d_imag(&f) / d__; z__1.r = d__1, z__1.i = d__2; ff.r = z__1.r, ff.i = z__1.i; } else { dr = safmx2 * f.r; di = safmx2 * d_imag(&f); d__ = dlapy2_(&dr, &di); d__1 = dr / d__; d__2 = di / d__; z__1.r = d__1, z__1.i = d__2; ff.r = z__1.r, ff.i = z__1.i; } d__1 = gs.r / g2s; d__2 = -d_imag(&gs) / g2s; z__2.r = d__1, z__2.i = d__2; z__1.r = ff.r * z__2.r - ff.i * z__2.i, z__1.i = ff.r * z__2.i + ff.i * z__2.r; sn.r = z__1.r, sn.i = z__1.i; z__2.r = cs * f.r, z__2.i = cs * f.i; z__3.r = sn.r * g.r - sn.i * g.i, z__3.i = sn.r * g.i + sn.i * g.r; z__1.r = z__2.r + z__3.r, z__1.i = z__2.i + z__3.i; r__.r = z__1.r, r__.i = z__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.); /* Do the F2S(real)*FS(complex) multiply with two real multiplies */ d__1 = f2s * fs.r; d__2 = f2s * d_imag(&fs); z__1.r = d__1, z__1.i = d__2; r__.r = z__1.r, r__.i = z__1.i; cs = 1. / f2s; d__ = f2 + g2; /* Do complex/real division explicitly with two real divisions */ d__1 = r__.r / d__; d__2 = d_imag(&r__) / d__; z__1.r = d__1, z__1.i = d__2; sn.r = z__1.r, sn.i = z__1.i; d_cnjg(&z__2, &gs); z__1.r = sn.r * z__2.r - sn.i * z__2.i, z__1.i = sn.r * z__2.i + sn.i * z__2.r; sn.r = z__1.r, sn.i = z__1.i; if (count != 0) { if (count > 0) { i__2 = count; for (j = 1; j <= i__2; ++j) { z__1.r = safmx2 * r__.r, z__1.i = safmx2 * r__.i; r__.r = z__1.r, r__.i = z__1.i; /* L30: */ } } else { i__2 = -count; for (j = 1; j <= i__2; ++j) { z__1.r = safmn2 * r__.r, z__1.i = safmn2 * r__.i; r__.r = z__1.r, r__.i = z__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 ZLARGV */ } /* zlargv_ */