OpenBLAS/lapack-netlib/SRC/dlanv2.c

/* f2c.h  --  Standard Fortran to C header file */

/**  barf  [ba:rf]  2.  "He suggested using FORTRAN, and everybody barfed."

	- From The Shogakukan DICTIONARY OF NEW ENGLISH (Second edition) */

#ifndef F2C_INCLUDE
#define F2C_INCLUDE

#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <complex.h>
#ifdef complex
#undef complex
#endif
#ifdef I
#undef I
#endif

typedef int integer;
typedef unsigned int uinteger;
typedef char *address;
typedef short int shortint;
typedef float real;
typedef double doublereal;
typedef struct { real r, i; } complex;
typedef struct { doublereal r, i; } doublecomplex;
static inline _Complex float Cf(complex *z) {return z->r + z->i*_Complex_I;}
static inline _Complex double Cd(doublecomplex *z) {return z->r + z->i*_Complex_I;}
static inline _Complex float * _pCf(complex *z) {return (_Complex float*)z;}
static inline _Complex double * _pCd(doublecomplex *z) {return (_Complex double*)z;}
#define pCf(z) (*_pCf(z))
#define pCd(z) (*_pCd(z))
typedef int logical;
typedef short int shortlogical;
typedef char logical1;
typedef char integer1;

#define TRUE_ (1)
#define FALSE_ (0)

/* Extern is for use with -E */
#ifndef Extern
#define Extern extern
#endif

/* I/O stuff */

typedef int flag;
typedef int ftnlen;
typedef int ftnint;

/*external read, write*/
typedef struct
{	flag cierr;
	ftnint ciunit;
	flag ciend;
	char *cifmt;
	ftnint cirec;
} cilist;

/*internal read, write*/
typedef struct
{	flag icierr;
	char *iciunit;
	flag iciend;
	char *icifmt;
	ftnint icirlen;
	ftnint icirnum;
} icilist;

/*open*/
typedef struct
{	flag oerr;
	ftnint ounit;
	char *ofnm;
	ftnlen ofnmlen;
	char *osta;
	char *oacc;
	char *ofm;
	ftnint orl;
	char *oblnk;
} olist;

/*close*/
typedef struct
{	flag cerr;
	ftnint cunit;
	char *csta;
} cllist;

/*rewind, backspace, endfile*/
typedef struct
{	flag aerr;
	ftnint aunit;
} alist;

/* inquire */
typedef struct
{	flag inerr;
	ftnint inunit;
	char *infile;
	ftnlen infilen;
	ftnint	*inex;	/*parameters in standard's order*/
	ftnint	*inopen;
	ftnint	*innum;
	ftnint	*innamed;
	char	*inname;
	ftnlen	innamlen;
	char	*inacc;
	ftnlen	inacclen;
	char	*inseq;
	ftnlen	inseqlen;
	char 	*indir;
	ftnlen	indirlen;
	char	*infmt;
	ftnlen	infmtlen;
	char	*inform;
	ftnint	informlen;
	char	*inunf;
	ftnlen	inunflen;
	ftnint	*inrecl;
	ftnint	*innrec;
	char	*inblank;
	ftnlen	inblanklen;
} inlist;

#define VOID void

union Multitype {	/* for multiple entry points */
	integer1 g;
	shortint h;
	integer i;
	/* longint j; */
	real r;
	doublereal d;
	complex c;
	doublecomplex z;
	};

typedef union Multitype Multitype;

struct Vardesc {	/* for Namelist */
	char *name;
	char *addr;
	ftnlen *dims;
	int  type;
	};
typedef struct Vardesc Vardesc;

struct Namelist {
	char *name;
	Vardesc **vars;
	int nvars;
	};
typedef struct Namelist Namelist;

#define abs(x) ((x) >= 0 ? (x) : -(x))
#define dabs(x) (fabs(x))
#define f2cmin(a,b) ((a) <= (b) ? (a) : (b))
#define f2cmax(a,b) ((a) >= (b) ? (a) : (b))
#define dmin(a,b) (f2cmin(a,b))
#define dmax(a,b) (f2cmax(a,b))
#define bit_test(a,b)	((a) >> (b) & 1)
#define bit_clear(a,b)	((a) & ~((uinteger)1 << (b)))
#define bit_set(a,b)	((a) |  ((uinteger)1 << (b)))

#define abort_() { sig_die("Fortran abort routine called", 1); }
#define c_abs(z) (cabsf(Cf(z)))
#define c_cos(R,Z) { pCf(R)=ccos(Cf(Z)); }
#define c_div(c, a, b) {pCf(c) = Cf(a)/Cf(b);}
#define z_div(c, a, b) {pCd(c) = Cd(a)/Cd(b);}
#define c_exp(R, Z) {pCf(R) = cexpf(Cf(Z));}
#define c_log(R, Z) {pCf(R) = clogf(Cf(Z));}
#define c_sin(R, Z) {pCf(R) = csinf(Cf(Z));}
//#define c_sqrt(R, Z) {*(R) = csqrtf(Cf(Z));}
#define c_sqrt(R, Z) {pCf(R) = csqrtf(Cf(Z));}
#define d_abs(x) (fabs(*(x)))
#define d_acos(x) (acos(*(x)))
#define d_asin(x) (asin(*(x)))
#define d_atan(x) (atan(*(x)))
#define d_atn2(x, y) (atan2(*(x),*(y)))
#define d_cnjg(R, Z) { pCd(R) = conj(Cd(Z)); }
#define r_cnjg(R, Z) { pCf(R) = conj(Cf(Z)); }
#define d_cos(x) (cos(*(x)))
#define d_cosh(x) (cosh(*(x)))
#define d_dim(__a, __b) ( *(__a) > *(__b) ? *(__a) - *(__b) : 0.0 )
#define d_exp(x) (exp(*(x)))
#define d_imag(z) (cimag(Cd(z)))
#define r_imag(z) (cimag(Cf(z)))
#define d_int(__x) (*(__x)>0 ? floor(*(__x)) : -floor(- *(__x)))
#define r_int(__x) (*(__x)>0 ? floor(*(__x)) : -floor(- *(__x)))
#define d_lg10(x) ( 0.43429448190325182765 * log(*(x)) )
#define r_lg10(x) ( 0.43429448190325182765 * log(*(x)) )
#define d_log(x) (log(*(x)))
#define d_mod(x, y) (fmod(*(x), *(y)))
#define u_nint(__x) ((__x)>=0 ? floor((__x) + .5) : -floor(.5 - (__x)))
#define d_nint(x) u_nint(*(x))
#define u_sign(__a,__b) ((__b) >= 0 ? ((__a) >= 0 ? (__a) : -(__a)) : -((__a) >= 0 ? (__a) : -(__a)))
#define d_sign(a,b) u_sign(*(a),*(b))
#define r_sign(a,b) u_sign(*(a),*(b))
#define d_sin(x) (sin(*(x)))
#define d_sinh(x) (sinh(*(x)))
#define d_sqrt(x) (sqrt(*(x)))
#define d_tan(x) (tan(*(x)))
#define d_tanh(x) (tanh(*(x)))
#define i_abs(x) abs(*(x))
#define i_dnnt(x) ((integer)u_nint(*(x)))
#define i_len(s, n) (n)
#define i_nint(x) ((integer)u_nint(*(x)))
#define i_sign(a,b) ((integer)u_sign((integer)*(a),(integer)*(b)))
#define pow_dd(ap, bp) ( pow(*(ap), *(bp)))
#define pow_si(B,E) spow_ui(*(B),*(E))
#define pow_ri(B,E) spow_ui(*(B),*(E))
#define pow_di(B,E) dpow_ui(*(B),*(E))
#define pow_zi(p, a, b) {pCd(p) = zpow_ui(Cd(a), *(b));}
#define pow_ci(p, a, b) {pCf(p) = cpow_ui(Cf(a), *(b));}
#define pow_zz(R,A,B) {pCd(R) = cpow(Cd(A),*(B));}
#define s_cat(lpp, rpp, rnp, np, llp) { 	ftnlen i, nc, ll; char *f__rp, *lp; 	ll = (llp); lp = (lpp); 	for(i=0; i < (int)*(np); ++i) {         	nc = ll; 	        if((rnp)[i] < nc) nc = (rnp)[i]; 	        ll -= nc;         	f__rp = (rpp)[i]; 	        while(--nc >= 0) *lp++ = *(f__rp)++;         } 	while(--ll >= 0) *lp++ = ' '; }
#define s_cmp(a,b,c,d) ((integer)strncmp((a),(b),f2cmin((c),(d))))
#define s_copy(A,B,C,D) { int __i,__m; for (__i=0, __m=f2cmin((C),(D)); __i<__m && (B)[__i] != 0; ++__i) (A)[__i] = (B)[__i]; }
#define sig_die(s, kill) { exit(1); }
#define s_stop(s, n) {exit(0);}
static char junk[] = "\n@(#)LIBF77 VERSION 19990503\n";
#define z_abs(z) (cabs(Cd(z)))
#define z_exp(R, Z) {pCd(R) = cexp(Cd(Z));}
#define z_sqrt(R, Z) {pCd(R) = csqrt(Cd(Z));}
#define myexit_() break;
#define mycycle() continue;
#define myceiling(w) {ceil(w)}
#define myhuge(w) {HUGE_VAL}
//#define mymaxloc_(w,s,e,n) {if (sizeof(*(w)) == sizeof(double)) dmaxloc_((w),*(s),*(e),n); else dmaxloc_((w),*(s),*(e),n);}
#define mymaxloc(w,s,e,n) {dmaxloc_(w,*(s),*(e),n)}

/* procedure parameter types for -A and -C++ */

#define F2C_proc_par_types 1
#ifdef __cplusplus
typedef logical (*L_fp)(...);
#else
typedef logical (*L_fp)();
#endif

static float spow_ui(float x, integer n) {
	float pow=1.0; unsigned long int u;
	if(n != 0) {
		if(n < 0) n = -n, x = 1/x;
		for(u = n; ; ) {
			if(u & 01) pow *= x;
			if(u >>= 1) x *= x;
			else break;
		}
	}
	return pow;
}
static double dpow_ui(double x, integer n) {
	double pow=1.0; unsigned long int u;
	if(n != 0) {
		if(n < 0) n = -n, x = 1/x;
		for(u = n; ; ) {
			if(u & 01) pow *= x;
			if(u >>= 1) x *= x;
			else break;
		}
	}
	return pow;
}
static _Complex float cpow_ui(_Complex float x, integer n) {
	_Complex float pow=1.0; unsigned long int u;
	if(n != 0) {
		if(n < 0) n = -n, x = 1/x;
		for(u = n; ; ) {
			if(u & 01) pow *= x;
			if(u >>= 1) x *= x;
			else break;
		}
	}
	return pow;
}
static _Complex double zpow_ui(_Complex double x, integer n) {
	_Complex double pow=1.0; unsigned long int u;
	if(n != 0) {
		if(n < 0) n = -n, x = 1/x;
		for(u = n; ; ) {
			if(u & 01) pow *= x;
			if(u >>= 1) x *= x;
			else break;
		}
	}
	return pow;
}
static integer pow_ii(integer x, integer n) {
	integer pow; unsigned long int u;
	if (n <= 0) {
		if (n == 0 || x == 1) pow = 1;
		else if (x != -1) pow = x == 0 ? 1/x : 0;
		else n = -n;
	}
	if ((n > 0) || !(n == 0 || x == 1 || x != -1)) {
		u = n;
		for(pow = 1; ; ) {
			if(u & 01) pow *= x;
			if(u >>= 1) x *= x;
			else break;
		}
	}
	return pow;
}
static integer dmaxloc_(double *w, integer s, integer e, integer *n)
{
	double m; integer i, mi;
	for(m=w[s-1], mi=s, i=s+1; i<=e; i++)
		if (w[i-1]>m) mi=i ,m=w[i-1];
	return mi-s+1;
}
static integer smaxloc_(float *w, integer s, integer e, integer *n)
{
	float m; integer i, mi;
	for(m=w[s-1], mi=s, i=s+1; i<=e; i++)
		if (w[i-1]>m) mi=i ,m=w[i-1];
	return mi-s+1;
}
static inline void cdotc_(complex *z, integer *n_, complex *x, integer *incx_, complex *y, integer *incy_) {
	integer n = *n_, incx = *incx_, incy = *incy_, i;
	_Complex float zdotc = 0.0;
	if (incx == 1 && incy == 1) {
		for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
			zdotc += conjf(Cf(&x[i])) * Cf(&y[i]);
		}
	} else {
		for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
			zdotc += conjf(Cf(&x[i*incx])) * Cf(&y[i*incy]);
		}
	}
	pCf(z) = zdotc;
}
static inline void zdotc_(doublecomplex *z, integer *n_, doublecomplex *x, integer *incx_, doublecomplex *y, integer *incy_) {
	integer n = *n_, incx = *incx_, incy = *incy_, i;
	_Complex double zdotc = 0.0;
	if (incx == 1 && incy == 1) {
		for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
			zdotc += conj(Cd(&x[i])) * Cd(&y[i]);
		}
	} else {
		for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
			zdotc += conj(Cd(&x[i*incx])) * Cd(&y[i*incy]);
		}
	}
	pCd(z) = zdotc;
}	
static inline void cdotu_(complex *z, integer *n_, complex *x, integer *incx_, complex *y, integer *incy_) {
	integer n = *n_, incx = *incx_, incy = *incy_, i;
	_Complex float zdotc = 0.0;
	if (incx == 1 && incy == 1) {
		for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
			zdotc += Cf(&x[i]) * Cf(&y[i]);
		}
	} else {
		for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
			zdotc += Cf(&x[i*incx]) * Cf(&y[i*incy]);
		}
	}
	pCf(z) = zdotc;
}
static inline void zdotu_(doublecomplex *z, integer *n_, doublecomplex *x, integer *incx_, doublecomplex *y, integer *incy_) {
	integer n = *n_, incx = *incx_, incy = *incy_, i;
	_Complex double zdotc = 0.0;
	if (incx == 1 && incy == 1) {
		for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
			zdotc += Cd(&x[i]) * Cd(&y[i]);
		}
	} else {
		for (i=0;i<n;i++) { /* zdotc = zdotc + dconjg(x(i))* y(i) */
			zdotc += Cd(&x[i*incx]) * Cd(&y[i*incy]);
		}
	}
	pCd(z) = zdotc;
}
#endif
/*  -- translated by f2c (version 20000121).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/



/* Table of constant values */

static doublereal c_b6 = 1.;

/* > \brief \b DLANV2 computes the Schur factorization of a real 2-by-2 nonsymmetric matrix in standard form. 
*/

/*  =========== DOCUMENTATION =========== */

/* Online html documentation available at */
/*            http://www.netlib.org/lapack/explore-html/ */

/* > \htmlonly */
/* > Download DLANV2 + dependencies */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlanv2.
f"> */
/* > [TGZ]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlanv2.
f"> */
/* > [ZIP]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlanv2.
f"> */
/* > [TXT]</a> */
/* > \endhtmlonly */

/*  Definition: */
/*  =========== */

/*       SUBROUTINE DLANV2( A, B, C, D, RT1R, RT1I, RT2R, RT2I, CS, SN ) */

/*       DOUBLE PRECISION   A, B, C, CS, D, RT1I, RT1R, RT2I, RT2R, SN */


/* > \par Purpose: */
/*  ============= */
/* > */
/* > \verbatim */
/* > */
/* > DLANV2 computes the Schur factorization of a real 2-by-2 nonsymmetric */
/* > matrix in standard form: */
/* > */
/* >      [ A  B ] = [ CS -SN ] [ AA  BB ] [ CS  SN ] */
/* >      [ C  D ]   [ SN  CS ] [ CC  DD ] [-SN  CS ] */
/* > */
/* > where either */
/* > 1) CC = 0 so that AA and DD are real eigenvalues of the matrix, or */
/* > 2) AA = DD and BB*CC < 0, so that AA + or - sqrt(BB*CC) are complex */
/* > conjugate eigenvalues. */
/* > \endverbatim */

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

/* > \param[in,out] A */
/* > \verbatim */
/* >          A is DOUBLE PRECISION */
/* > \endverbatim */
/* > */
/* > \param[in,out] B */
/* > \verbatim */
/* >          B is DOUBLE PRECISION */
/* > \endverbatim */
/* > */
/* > \param[in,out] C */
/* > \verbatim */
/* >          C is DOUBLE PRECISION */
/* > \endverbatim */
/* > */
/* > \param[in,out] D */
/* > \verbatim */
/* >          D is DOUBLE PRECISION */
/* >          On entry, the elements of the input matrix. */
/* >          On exit, they are overwritten by the elements of the */
/* >          standardised Schur form. */
/* > \endverbatim */
/* > */
/* > \param[out] RT1R */
/* > \verbatim */
/* >          RT1R is DOUBLE PRECISION */
/* > \endverbatim */
/* > */
/* > \param[out] RT1I */
/* > \verbatim */
/* >          RT1I is DOUBLE PRECISION */
/* > \endverbatim */
/* > */
/* > \param[out] RT2R */
/* > \verbatim */
/* >          RT2R is DOUBLE PRECISION */
/* > \endverbatim */
/* > */
/* > \param[out] RT2I */
/* > \verbatim */
/* >          RT2I is DOUBLE PRECISION */
/* >          The real and imaginary parts of the eigenvalues. If the */
/* >          eigenvalues are a complex conjugate pair, RT1I > 0. */
/* > \endverbatim */
/* > */
/* > \param[out] CS */
/* > \verbatim */
/* >          CS is DOUBLE PRECISION */
/* > \endverbatim */
/* > */
/* > \param[out] SN */
/* > \verbatim */
/* >          SN is DOUBLE PRECISION */
/* >          Parameters of the rotation matrix. */
/* > \endverbatim */

/*  Authors: */
/*  ======== */

/* > \author Univ. of Tennessee */
/* > \author Univ. of California Berkeley */
/* > \author Univ. of Colorado Denver */
/* > \author NAG Ltd. */

/* > \date December 2016 */

/* > \ingroup doubleOTHERauxiliary */

/* > \par Further Details: */
/*  ===================== */
/* > */
/* > \verbatim */
/* > */
/* >  Modified by V. Sima, Research Institute for Informatics, Bucharest, */
/* >  Romania, to reduce the risk of cancellation errors, */
/* >  when computing real eigenvalues, and to ensure, if possible, that */
/* >  abs(RT1R) >= abs(RT2R). */
/* > \endverbatim */
/* > */
/*  ===================================================================== */
/* Subroutine */ int dlanv2_(doublereal *a, doublereal *b, doublereal *c__, 
	doublereal *d__, doublereal *rt1r, doublereal *rt1i, doublereal *rt2r,
	 doublereal *rt2i, doublereal *cs, doublereal *sn)
{
    /* System generated locals */
    integer i__1;
    doublereal d__1, d__2;

    /* Local variables */
    doublereal temp, p, scale, bcmax, z__, bcmis, sigma;
    integer count;
    doublereal safmn2;
    extern doublereal dlapy2_(doublereal *, doublereal *);
    doublereal safmx2, aa, bb, cc, dd;
    extern doublereal dlamch_(char *);
    doublereal safmin, cs1, sn1, sab, sac, eps, tau;


/*  -- LAPACK auxiliary routine (version 3.7.0) -- */
/*  -- LAPACK is a software package provided by Univ. of Tennessee,    -- */
/*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/*     December 2016 */


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


    safmin = dlamch_("S");
    eps = dlamch_("P");
    d__1 = dlamch_("B");
    i__1 = (integer) (log(safmin / eps) / log(dlamch_("B")) / 2.);
    safmn2 = pow_di(&d__1, &i__1);
    safmx2 = 1. / safmn2;
    if (*c__ == 0.) {
	*cs = 1.;
	*sn = 0.;

    } else if (*b == 0.) {

/*        Swap rows and columns */

	*cs = 0.;
	*sn = 1.;
	temp = *d__;
	*d__ = *a;
	*a = temp;
	*b = -(*c__);
	*c__ = 0.;

    } else if (*a - *d__ == 0. && d_sign(&c_b6, b) != d_sign(&c_b6, c__)) {
	*cs = 1.;
	*sn = 0.;

    } else {

	temp = *a - *d__;
	p = temp * .5;
/* Computing MAX */
	d__1 = abs(*b), d__2 = abs(*c__);
	bcmax = f2cmax(d__1,d__2);
/* Computing MIN */
	d__1 = abs(*b), d__2 = abs(*c__);
	bcmis = f2cmin(d__1,d__2) * d_sign(&c_b6, b) * d_sign(&c_b6, c__);
/* Computing MAX */
	d__1 = abs(p);
	scale = f2cmax(d__1,bcmax);
	z__ = p / scale * p + bcmax / scale * bcmis;

/*        If Z is of the order of the machine accuracy, postpone the */
/*        decision on the nature of eigenvalues */

	if (z__ >= eps * 4.) {

/*           Real eigenvalues. Compute A and D. */

	    d__1 = sqrt(scale) * sqrt(z__);
	    z__ = p + d_sign(&d__1, &p);
	    *a = *d__ + z__;
	    *d__ -= bcmax / z__ * bcmis;

/*           Compute B and the rotation matrix */

	    tau = dlapy2_(c__, &z__);
	    *cs = z__ / tau;
	    *sn = *c__ / tau;
	    *b -= *c__;
	    *c__ = 0.;

	} else {

/*           Complex eigenvalues, or real (almost) equal eigenvalues. */
/*           Make diagonal elements equal. */

	    count = 0;
	    sigma = *b + *c__;
L10:
	    ++count;
/* Computing MAX */
	    d__1 = abs(temp), d__2 = abs(sigma);
	    scale = f2cmax(d__1,d__2);
	    if (scale >= safmx2) {
		sigma *= safmn2;
		temp *= safmn2;
		if (count <= 20) {
		    goto L10;
		}
	    }
	    if (scale <= safmn2) {
		sigma *= safmx2;
		temp *= safmx2;
		if (count <= 20) {
		    goto L10;
		}
	    }
	    p = temp * .5;
	    tau = dlapy2_(&sigma, &temp);
	    *cs = sqrt((abs(sigma) / tau + 1.) * .5);
	    *sn = -(p / (tau * *cs)) * d_sign(&c_b6, &sigma);

/*           Compute [ AA  BB ] = [ A  B ] [ CS -SN ] */
/*                   [ CC  DD ]   [ C  D ] [ SN  CS ] */

	    aa = *a * *cs + *b * *sn;
	    bb = -(*a) * *sn + *b * *cs;
	    cc = *c__ * *cs + *d__ * *sn;
	    dd = -(*c__) * *sn + *d__ * *cs;

/*           Compute [ A  B ] = [ CS  SN ] [ AA  BB ] */
/*                   [ C  D ]   [-SN  CS ] [ CC  DD ] */

	    *a = aa * *cs + cc * *sn;
	    *b = bb * *cs + dd * *sn;
	    *c__ = -aa * *sn + cc * *cs;
	    *d__ = -bb * *sn + dd * *cs;

	    temp = (*a + *d__) * .5;
	    *a = temp;
	    *d__ = temp;

	    if (*c__ != 0.) {
		if (*b != 0.) {
		    if (d_sign(&c_b6, b) == d_sign(&c_b6, c__)) {

/*                    Real eigenvalues: reduce to upper triangular form */

			sab = sqrt((abs(*b)));
			sac = sqrt((abs(*c__)));
			d__1 = sab * sac;
			p = d_sign(&d__1, c__);
			tau = 1. / sqrt((d__1 = *b + *c__, abs(d__1)));
			*a = temp + p;
			*d__ = temp - p;
			*b -= *c__;
			*c__ = 0.;
			cs1 = sab * tau;
			sn1 = sac * tau;
			temp = *cs * cs1 - *sn * sn1;
			*sn = *cs * sn1 + *sn * cs1;
			*cs = temp;
		    }
		} else {
		    *b = -(*c__);
		    *c__ = 0.;
		    temp = *cs;
		    *cs = -(*sn);
		    *sn = temp;
		}
	    }
	}

    }

/*     Store eigenvalues in (RT1R,RT1I) and (RT2R,RT2I). */

    *rt1r = *a;
    *rt2r = *d__;
    if (*c__ == 0.) {
	*rt1i = 0.;
	*rt2i = 0.;
    } else {
	*rt1i = sqrt((abs(*b))) * sqrt((abs(*c__)));
	*rt2i = -(*rt1i);
    }
    return 0;

/*     End of DLANV2 */

} /* dlanv2_ */