text: /* ztgevc.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"
  
  /* Table of constant values */
  
  static doublecomplex c_b1 = {0.,0.};
  static doublecomplex c_b2 = {1.,0.};
  static integer c__1 = 1;
  
  /* Subroutine */ int ztgevc_(char *side, char *howmny, logical *select, 
  	integer *n, doublecomplex *s, integer *lds, doublecomplex *p, integer 
  	*ldp, doublecomplex *vl, integer *ldvl, doublecomplex *vr, integer *
  	ldvr, integer *mm, integer *m, doublecomplex *work, doublereal *rwork, 
  	 integer *info)
  {
      /* System generated locals */
      integer p_dim1, p_offset, s_dim1, s_offset, vl_dim1, vl_offset, vr_dim1, 
  	    vr_offset, i__1, i__2, i__3, i__4, i__5;
      doublereal d__1, d__2, d__3, d__4, d__5, d__6;
      doublecomplex z__1, z__2, z__3, z__4;
  
      /* Builtin functions */
      double d_imag(doublecomplex *);
      void d_cnjg(doublecomplex *, doublecomplex *);
  
      /* Local variables */
      doublecomplex d__;
      integer i__, j;
      doublecomplex ca, cb;
      integer je, im, jr;
      doublereal big;
      logical lsa, lsb;
      doublereal ulp;
      doublecomplex sum;
      integer ibeg, ieig, iend;
      doublereal dmin__;
      integer isrc;
      doublereal temp;
      doublecomplex suma, sumb;
      doublereal xmax, scale;
      logical ilall;
      integer iside;
      doublereal sbeta;
      extern logical lsame_(char *, char *);
      doublereal small;
      logical compl;
      doublereal anorm, bnorm;
      logical compr;
      extern /* Subroutine */ int zgemv_(char *, integer *, integer *, 
  	    doublecomplex *, doublecomplex *, integer *, doublecomplex *, 
  	    integer *, doublecomplex *, doublecomplex *, integer *), 
  	    dlabad_(doublereal *, doublereal *);
      logical ilbbad;
      doublereal acoefa, bcoefa, acoeff;
      doublecomplex bcoeff;
      logical ilback;
      doublereal ascale, bscale;
      extern doublereal dlamch_(char *);
      doublecomplex salpha;
      doublereal safmin;
      extern /* Subroutine */ int xerbla_(char *, integer *);
      doublereal bignum;
      logical ilcomp;
      extern /* Double Complex */ VOID zladiv_(doublecomplex *, doublecomplex *, 
  	     doublecomplex *);
      integer ihwmny;
  
  
  /*  -- LAPACK routine (version 3.2) -- */
  /*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
  /*     November 2006 */
  
  /*     .. Scalar Arguments .. */
  /*     .. */
  /*     .. Array Arguments .. */
  /*     .. */
  
  
  /*  Purpose */
  /*  ======= */
  
  /*  ZTGEVC computes some or all of the right and/or left eigenvectors of */
  /*  a pair of complex matrices (S,P), where S and P are upper triangular. */
  /*  Matrix pairs of this type are produced by the generalized Schur */
  /*  factorization of a complex matrix pair (A,B): */
  
  /*     A = Q*S*Z**H,  B = Q*P*Z**H */
  
  /*  as computed by ZGGHRD + ZHGEQZ. */
  
  /*  The right eigenvector x and the left eigenvector y of (S,P) */
  /*  corresponding to an eigenvalue w are defined by: */
  
  /*     S*x = w*P*x,  (y**H)*S = w*(y**H)*P, */
  
  /*  where y**H denotes the conjugate tranpose of y. */
  /*  The eigenvalues are not input to this routine, but are computed */
  /*  directly from the diagonal elements of S and P. */
  
  /*  This routine returns the matrices X and/or Y of right and left */
  /*  eigenvectors of (S,P), or the products Z*X and/or Q*Y, */
  /*  where Z and Q are input matrices. */
  /*  If Q and Z are the unitary factors from the generalized Schur */
  /*  factorization of a matrix pair (A,B), then Z*X and Q*Y */
  /*  are the matrices of right and left eigenvectors of (A,B). */
  
  /*  Arguments */
  /*  ========= */
  
  /*  SIDE    (input) CHARACTER*1 */
  /*          = 'R': compute right eigenvectors only; */
  /*          = 'L': compute left eigenvectors only; */
  /*          = 'B': compute both right and left eigenvectors. */
  
  /*  HOWMNY  (input) CHARACTER*1 */
  /*          = 'A': compute all right and/or left eigenvectors; */
  /*          = 'B': compute all right and/or left eigenvectors, */
  /*                 backtransformed by the matrices in VR and/or VL; */
  /*          = 'S': compute selected right and/or left eigenvectors, */
  /*                 specified by the logical array SELECT. */
  
  /*  SELECT  (input) LOGICAL array, dimension (N) */
  /*          If HOWMNY='S', SELECT specifies the eigenvectors to be */
  /*          computed.  The eigenvector corresponding to the j-th */
  /*          eigenvalue is computed if SELECT(j) = .TRUE.. */
  /*          Not referenced if HOWMNY = 'A' or 'B'. */
  
  /*  N       (input) INTEGER */
  /*          The order of the matrices S and P.  N >= 0. */
  
  /*  S       (input) COMPLEX*16 array, dimension (LDS,N) */
  /*          The upper triangular matrix S from a generalized Schur */
  /*          factorization, as computed by ZHGEQZ. */
  
  /*  LDS     (input) INTEGER */
  /*          The leading dimension of array S.  LDS >= max(1,N). */
  
  /*  P       (input) COMPLEX*16 array, dimension (LDP,N) */
  /*          The upper triangular matrix P from a generalized Schur */
  /*          factorization, as computed by ZHGEQZ.  P must have real */
  /*          diagonal elements. */
  
  /*  LDP     (input) INTEGER */
  /*          The leading dimension of array P.  LDP >= max(1,N). */
  
  /*  VL      (input/output) COMPLEX*16 array, dimension (LDVL,MM) */
  /*          On entry, if SIDE = 'L' or 'B' and HOWMNY = 'B', VL must */
  /*          contain an N-by-N matrix Q (usually the unitary matrix Q */
  /*          of left Schur vectors returned by ZHGEQZ). */
  /*          On exit, if SIDE = 'L' or 'B', VL contains: */
  /*          if HOWMNY = 'A', the matrix Y of left eigenvectors of (S,P); */
  /*          if HOWMNY = 'B', the matrix Q*Y; */
  /*          if HOWMNY = 'S', the left eigenvectors of (S,P) specified by */
  /*                      SELECT, stored consecutively in the columns of */
  /*                      VL, in the same order as their eigenvalues. */
  /*          Not referenced if SIDE = 'R'. */
  
  /*  LDVL    (input) INTEGER */
  /*          The leading dimension of array VL.  LDVL >= 1, and if */
  /*          SIDE = 'L' or 'l' or 'B' or 'b', LDVL >= N. */
  
  /*  VR      (input/output) COMPLEX*16 array, dimension (LDVR,MM) */
  /*          On entry, if SIDE = 'R' or 'B' and HOWMNY = 'B', VR must */
  /*          contain an N-by-N matrix Q (usually the unitary matrix Z */
  /*          of right Schur vectors returned by ZHGEQZ). */
  /*          On exit, if SIDE = 'R' or 'B', VR contains: */
  /*          if HOWMNY = 'A', the matrix X of right eigenvectors of (S,P); */
  /*          if HOWMNY = 'B', the matrix Z*X; */
  /*          if HOWMNY = 'S', the right eigenvectors of (S,P) specified by */
  /*                      SELECT, stored consecutively in the columns of */
  /*                      VR, in the same order as their eigenvalues. */
  /*          Not referenced if SIDE = 'L'. */
  
  /*  LDVR    (input) INTEGER */
  /*          The leading dimension of the array VR.  LDVR >= 1, and if */
  /*          SIDE = 'R' or 'B', LDVR >= N. */
  
  /*  MM      (input) INTEGER */
  /*          The number of columns in the arrays VL and/or VR. MM >= M. */
  
  /*  M       (output) INTEGER */
  /*          The number of columns in the arrays VL and/or VR actually */
  /*          used to store the eigenvectors.  If HOWMNY = 'A' or 'B', M */
  /*          is set to N.  Each selected eigenvector occupies one column. */
  
  /*  WORK    (workspace) COMPLEX*16 array, dimension (2*N) */
  
  /*  RWORK   (workspace) DOUBLE PRECISION array, dimension (2*N) */
  
  /*  INFO    (output) INTEGER */
  /*          = 0:  successful exit. */
  /*          < 0:  if INFO = -i, the i-th argument had an illegal value. */
  
  /*  ===================================================================== */
  
  /*     .. Parameters .. */
  /*     .. */
  /*     .. Local Scalars .. */
  /*     .. */
  /*     .. External Functions .. */
  /*     .. */
  /*     .. External Subroutines .. */
  /*     .. */
  /*     .. Intrinsic Functions .. */
  /*     .. */
  /*     .. Statement Functions .. */
  /*     .. */
  /*     .. Statement Function definitions .. */
  /*     .. */
  /*     .. Executable Statements .. */
  
  /*     Decode and Test the input parameters */
  
      /* Parameter adjustments */
      --select;
      s_dim1 = *lds;
      s_offset = 1 + s_dim1;
      s -= s_offset;
      p_dim1 = *ldp;
      p_offset = 1 + p_dim1;
      p -= p_offset;
      vl_dim1 = *ldvl;
      vl_offset = 1 + vl_dim1;
      vl -= vl_offset;
      vr_dim1 = *ldvr;
      vr_offset = 1 + vr_dim1;
      vr -= vr_offset;
      --work;
      --rwork;
  
      /* Function Body */
      if (lsame_(howmny, "A")) {
  	ihwmny = 1;
  	ilall = TRUE_;
  	ilback = FALSE_;
      } else if (lsame_(howmny, "S")) {
  	ihwmny = 2;
  	ilall = FALSE_;
  	ilback = FALSE_;
      } else if (lsame_(howmny, "B")) {
  	ihwmny = 3;
  	ilall = TRUE_;
  	ilback = TRUE_;
      } else {
  	ihwmny = -1;
      }
  
      if (lsame_(side, "R")) {
  	iside = 1;
  	compl = FALSE_;
  	compr = TRUE_;
      } else if (lsame_(side, "L")) {
  	iside = 2;
  	compl = TRUE_;
  	compr = FALSE_;
      } else if (lsame_(side, "B")) {
  	iside = 3;
  	compl = TRUE_;
  	compr = TRUE_;
      } else {
  	iside = -1;
      }
  
      *info = 0;
      if (iside < 0) {
  	*info = -1;
      } else if (ihwmny < 0) {
  	*info = -2;
      } else if (*n < 0) {
  	*info = -4;
      } else if (*lds < max(1,*n)) {
  	*info = -6;
      } else if (*ldp < max(1,*n)) {
  	*info = -8;
      }
      if (*info != 0) {
  	i__1 = -(*info);
  	xerbla_("ZTGEVC", &i__1);
  	return 0;
      }
  
  /*     Count the number of eigenvectors */
  
      if (! ilall) {
  	im = 0;
  	i__1 = *n;
  	for (j = 1; j <= i__1; ++j) {
  	    if (select[j]) {
  		++im;
  	    }
  /* L10: */
  	}
      } else {
  	im = *n;
      }
  
  /*     Check diagonal of B */
  
      ilbbad = FALSE_;
      i__1 = *n;
      for (j = 1; j <= i__1; ++j) {
  	if (d_imag(&p[j + j * p_dim1]) != 0.) {
  	    ilbbad = TRUE_;
  	}
  /* L20: */
      }
  
      if (ilbbad) {
  	*info = -7;
      } else if (compl && *ldvl < *n || *ldvl < 1) {
  	*info = -10;
      } else if (compr && *ldvr < *n || *ldvr < 1) {
  	*info = -12;
      } else if (*mm < im) {
  	*info = -13;
      }
      if (*info != 0) {
  	i__1 = -(*info);
  	xerbla_("ZTGEVC", &i__1);
  	return 0;
      }
  
  /*     Quick return if possible */
  
      *m = im;
      if (*n == 0) {
  	return 0;
      }
  
  /*     Machine Constants */
  
      safmin = dlamch_("Safe minimum");
      big = 1. / safmin;
      dlabad_(&safmin, &big);
      ulp = dlamch_("Epsilon") * dlamch_("Base");
      small = safmin * *n / ulp;
      big = 1. / small;
      bignum = 1. / (safmin * *n);
  
  /*     Compute the 1-norm of each column of the strictly upper triangular */
  /*     part of A and B to check for possible overflow in the triangular */
  /*     solver. */
  
      i__1 = s_dim1 + 1;
      anorm = (d__1 = s[i__1].r, abs(d__1)) + (d__2 = d_imag(&s[s_dim1 + 1]), 
  	    abs(d__2));
      i__1 = p_dim1 + 1;
      bnorm = (d__1 = p[i__1].r, abs(d__1)) + (d__2 = d_imag(&p[p_dim1 + 1]), 
  	    abs(d__2));
      rwork[1] = 0.;
      rwork[*n + 1] = 0.;
      i__1 = *n;
      for (j = 2; j <= i__1; ++j) {
  	rwork[j] = 0.;
  	rwork[*n + j] = 0.;
  	i__2 = j - 1;
  	for (i__ = 1; i__ <= i__2; ++i__) {
  	    i__3 = i__ + j * s_dim1;
  	    rwork[j] += (d__1 = s[i__3].r, abs(d__1)) + (d__2 = d_imag(&s[i__ 
  		    + j * s_dim1]), abs(d__2));
  	    i__3 = i__ + j * p_dim1;
  	    rwork[*n + j] += (d__1 = p[i__3].r, abs(d__1)) + (d__2 = d_imag(&
  		    p[i__ + j * p_dim1]), abs(d__2));
  /* L30: */
  	}
  /* Computing MAX */
  	i__2 = j + j * s_dim1;
  	d__3 = anorm, d__4 = rwork[j] + ((d__1 = s[i__2].r, abs(d__1)) + (
  		d__2 = d_imag(&s[j + j * s_dim1]), abs(d__2)));
  	anorm = max(d__3,d__4);
  /* Computing MAX */
  	i__2 = j + j * p_dim1;
  	d__3 = bnorm, d__4 = rwork[*n + j] + ((d__1 = p[i__2].r, abs(d__1)) + 
  		(d__2 = d_imag(&p[j + j * p_dim1]), abs(d__2)));
  	bnorm = max(d__3,d__4);
  /* L40: */
      }
  
      ascale = 1. / max(anorm,safmin);
      bscale = 1. / max(bnorm,safmin);
  
  /*     Left eigenvectors */
  
      if (compl) {
  	ieig = 0;
  
  /*        Main loop over eigenvalues */
  
  	i__1 = *n;
  	for (je = 1; je <= i__1; ++je) {
  	    if (ilall) {
  		ilcomp = TRUE_;
  	    } else {
  		ilcomp = select[je];
  	    }
  	    if (ilcomp) {
  		++ieig;
  
  		i__2 = je + je * s_dim1;
  		i__3 = je + je * p_dim1;
  		if ((d__2 = s[i__2].r, abs(d__2)) + (d__3 = d_imag(&s[je + je 
  			* s_dim1]), abs(d__3)) <= safmin && (d__1 = p[i__3].r,
  			 abs(d__1)) <= safmin) {
  
  /*                 Singular matrix pencil -- return unit eigenvector */
  
  		    i__2 = *n;
  		    for (jr = 1; jr <= i__2; ++jr) {
  			i__3 = jr + ieig * vl_dim1;
  			vl[i__3].r = 0., vl[i__3].i = 0.;
  /* L50: */
  		    }
  		    i__2 = ieig + ieig * vl_dim1;
  		    vl[i__2].r = 1., vl[i__2].i = 0.;
  		    goto L140;
  		}
  
  /*              Non-singular eigenvalue: */
  /*              Compute coefficients  a  and  b  in */
  /*                   H */
  /*                 y  ( a A - b B ) = 0 */
  
  /* Computing MAX */
  		i__2 = je + je * s_dim1;
  		i__3 = je + je * p_dim1;
  		d__4 = ((d__2 = s[i__2].r, abs(d__2)) + (d__3 = d_imag(&s[je 
  			+ je * s_dim1]), abs(d__3))) * ascale, d__5 = (d__1 = 
  			p[i__3].r, abs(d__1)) * bscale, d__4 = max(d__4,d__5);
  		temp = 1. / max(d__4,safmin);
  		i__2 = je + je * s_dim1;
  		z__2.r = temp * s[i__2].r, z__2.i = temp * s[i__2].i;
  		z__1.r = ascale * z__2.r, z__1.i = ascale * z__2.i;
  		salpha.r = z__1.r, salpha.i = z__1.i;
  		i__2 = je + je * p_dim1;
  		sbeta = temp * p[i__2].r * bscale;
  		acoeff = sbeta * ascale;
  		z__1.r = bscale * salpha.r, z__1.i = bscale * salpha.i;
  		bcoeff.r = z__1.r, bcoeff.i = z__1.i;
  
  /*              Scale to avoid underflow */
  
  		lsa = abs(sbeta) >= safmin && abs(acoeff) < small;
  		lsb = (d__1 = salpha.r, abs(d__1)) + (d__2 = d_imag(&salpha), 
  			abs(d__2)) >= safmin && (d__3 = bcoeff.r, abs(d__3)) 
  			+ (d__4 = d_imag(&bcoeff), abs(d__4)) < small;
  
  		scale = 1.;
  		if (lsa) {
  		    scale = small / abs(sbeta) * min(anorm,big);
  		}
  		if (lsb) {
  /* Computing MAX */
  		    d__3 = scale, d__4 = small / ((d__1 = salpha.r, abs(d__1))
  			     + (d__2 = d_imag(&salpha), abs(d__2))) * min(
  			    bnorm,big);
  		    scale = max(d__3,d__4);
  		}
  		if (lsa || lsb) {
  /* Computing MIN */
  /* Computing MAX */
  		    d__5 = 1., d__6 = abs(acoeff), d__5 = max(d__5,d__6), 
  			    d__6 = (d__1 = bcoeff.r, abs(d__1)) + (d__2 = 
  			    d_imag(&bcoeff), abs(d__2));
  		    d__3 = scale, d__4 = 1. / (safmin * max(d__5,d__6));
  		    scale = min(d__3,d__4);
  		    if (lsa) {
  			acoeff = ascale * (scale * sbeta);
  		    } else {
  			acoeff = scale * acoeff;
  		    }
  		    if (lsb) {
  			z__2.r = scale * salpha.r, z__2.i = scale * salpha.i;
  			z__1.r = bscale * z__2.r, z__1.i = bscale * z__2.i;
  			bcoeff.r = z__1.r, bcoeff.i = z__1.i;
  		    } else {
  			z__1.r = scale * bcoeff.r, z__1.i = scale * bcoeff.i;
  			bcoeff.r = z__1.r, bcoeff.i = z__1.i;
  		    }
  		}
  
  		acoefa = abs(acoeff);
  		bcoefa = (d__1 = bcoeff.r, abs(d__1)) + (d__2 = d_imag(&
  			bcoeff), abs(d__2));
  		xmax = 1.;
  		i__2 = *n;
  		for (jr = 1; jr <= i__2; ++jr) {
  		    i__3 = jr;
  		    work[i__3].r = 0., work[i__3].i = 0.;
  /* L60: */
  		}
  		i__2 = je;
  		work[i__2].r = 1., work[i__2].i = 0.;
  /* Computing MAX */
  		d__1 = ulp * acoefa * anorm, d__2 = ulp * bcoefa * bnorm, 
  			d__1 = max(d__1,d__2);
  		dmin__ = max(d__1,safmin);
  
  /*                                              H */
  /*              Triangular solve of  (a A - b B)  y = 0 */
  
  /*                                      H */
  /*              (rowwise in  (a A - b B) , or columnwise in a A - b B) */
  
  		i__2 = *n;
  		for (j = je + 1; j <= i__2; ++j) {
  
  /*                 Compute */
  /*                       j-1 */
  /*                 SUM = sum  conjg( a*S(k,j) - b*P(k,j) )*x(k) */
  /*                       k=je */
  /*                 (Scale if necessary) */
  
  		    temp = 1. / xmax;
  		    if (acoefa * rwork[j] + bcoefa * rwork[*n + j] > bignum * 
  			    temp) {
  			i__3 = j - 1;
  			for (jr = je; jr <= i__3; ++jr) {
  			    i__4 = jr;
  			    i__5 = jr;
  			    z__1.r = temp * work[i__5].r, z__1.i = temp * 
  				    work[i__5].i;
  			    work[i__4].r = z__1.r, work[i__4].i = z__1.i;
  /* L70: */
  			}
  			xmax = 1.;
  		    }
  		    suma.r = 0., suma.i = 0.;
  		    sumb.r = 0., sumb.i = 0.;
  
  		    i__3 = j - 1;
  		    for (jr = je; jr <= i__3; ++jr) {
  			d_cnjg(&z__3, &s[jr + j * s_dim1]);
  			i__4 = jr;
  			z__2.r = z__3.r * work[i__4].r - z__3.i * work[i__4]
  				.i, z__2.i = z__3.r * work[i__4].i + z__3.i * 
  				work[i__4].r;
  			z__1.r = suma.r + z__2.r, z__1.i = suma.i + z__2.i;
  			suma.r = z__1.r, suma.i = z__1.i;
  			d_cnjg(&z__3, &p[jr + j * p_dim1]);
  			i__4 = jr;
  			z__2.r = z__3.r * work[i__4].r - z__3.i * work[i__4]
  				.i, z__2.i = z__3.r * work[i__4].i + z__3.i * 
  				work[i__4].r;
  			z__1.r = sumb.r + z__2.r, z__1.i = sumb.i + z__2.i;
  			sumb.r = z__1.r, sumb.i = z__1.i;
  /* L80: */
  		    }
  		    z__2.r = acoeff * suma.r, z__2.i = acoeff * suma.i;
  		    d_cnjg(&z__4, &bcoeff);
  		    z__3.r = z__4.r * sumb.r - z__4.i * sumb.i, z__3.i = 
  			    z__4.r * sumb.i + z__4.i * sumb.r;
  		    z__1.r = z__2.r - z__3.r, z__1.i = z__2.i - z__3.i;
  		    sum.r = z__1.r, sum.i = z__1.i;
  
  /*                 Form x(j) = - SUM / conjg( a*S(j,j) - b*P(j,j) ) */
  
  /*                 with scaling and perturbation of the denominator */
  
  		    i__3 = j + j * s_dim1;
  		    z__3.r = acoeff * s[i__3].r, z__3.i = acoeff * s[i__3].i;
  		    i__4 = j + j * p_dim1;
  		    z__4.r = bcoeff.r * p[i__4].r - bcoeff.i * p[i__4].i, 
  			    z__4.i = bcoeff.r * p[i__4].i + bcoeff.i * p[i__4]
  			    .r;
  		    z__2.r = z__3.r - z__4.r, z__2.i = z__3.i - z__4.i;
  		    d_cnjg(&z__1, &z__2);
  		    d__.r = z__1.r, d__.i = z__1.i;
  		    if ((d__1 = d__.r, abs(d__1)) + (d__2 = d_imag(&d__), abs(
  			    d__2)) <= dmin__) {
  			z__1.r = dmin__, z__1.i = 0.;
  			d__.r = z__1.r, d__.i = z__1.i;
  		    }
  
  		    if ((d__1 = d__.r, abs(d__1)) + (d__2 = d_imag(&d__), abs(
  			    d__2)) < 1.) {
  			if ((d__1 = sum.r, abs(d__1)) + (d__2 = d_imag(&sum), 
  				abs(d__2)) >= bignum * ((d__3 = d__.r, abs(
  				d__3)) + (d__4 = d_imag(&d__), abs(d__4)))) {
  			    temp = 1. / ((d__1 = sum.r, abs(d__1)) + (d__2 = 
  				    d_imag(&sum), abs(d__2)));
  			    i__3 = j - 1;
  			    for (jr = je; jr <= i__3; ++jr) {
  				i__4 = jr;
  				i__5 = jr;
  				z__1.r = temp * work[i__5].r, z__1.i = temp * 
  					work[i__5].i;
  				work[i__4].r = z__1.r, work[i__4].i = z__1.i;
  /* L90: */
  			    }
  			    xmax = temp * xmax;
  			    z__1.r = temp * sum.r, z__1.i = temp * sum.i;
  			    sum.r = z__1.r, sum.i = z__1.i;
  			}
  		    }
  		    i__3 = j;
  		    z__2.r = -sum.r, z__2.i = -sum.i;
  		    zladiv_(&z__1, &z__2, &d__);
  		    work[i__3].r = z__1.r, work[i__3].i = z__1.i;
  /* Computing MAX */
  		    i__3 = j;
  		    d__3 = xmax, d__4 = (d__1 = work[i__3].r, abs(d__1)) + (
  			    d__2 = d_imag(&work[j]), abs(d__2));
  		    xmax = max(d__3,d__4);
  /* L100: */
  		}
  
  /*              Back transform eigenvector if HOWMNY='B'. */
  
  		if (ilback) {
  		    i__2 = *n + 1 - je;
  		    zgemv_("N", n, &i__2, &c_b2, &vl[je * vl_dim1 + 1], ldvl, 
  			    &work[je], &c__1, &c_b1, &work[*n + 1], &c__1);
  		    isrc = 2;
  		    ibeg = 1;
  		} else {
  		    isrc = 1;
  		    ibeg = je;
  		}
  
  /*              Copy and scale eigenvector into column of VL */
  
  		xmax = 0.;
  		i__2 = *n;
  		for (jr = ibeg; jr <= i__2; ++jr) {
  /* Computing MAX */
  		    i__3 = (isrc - 1) * *n + jr;
  		    d__3 = xmax, d__4 = (d__1 = work[i__3].r, abs(d__1)) + (
  			    d__2 = d_imag(&work[(isrc - 1) * *n + jr]), abs(
  			    d__2));
  		    xmax = max(d__3,d__4);
  /* L110: */
  		}
  
  		if (xmax > safmin) {
  		    temp = 1. / xmax;
  		    i__2 = *n;
  		    for (jr = ibeg; jr <= i__2; ++jr) {
  			i__3 = jr + ieig * vl_dim1;
  			i__4 = (isrc - 1) * *n + jr;
  			z__1.r = temp * work[i__4].r, z__1.i = temp * work[
  				i__4].i;
  			vl[i__3].r = z__1.r, vl[i__3].i = z__1.i;
  /* L120: */
  		    }
  		} else {
  		    ibeg = *n + 1;
  		}
  
  		i__2 = ibeg - 1;
  		for (jr = 1; jr <= i__2; ++jr) {
  		    i__3 = jr + ieig * vl_dim1;
  		    vl[i__3].r = 0., vl[i__3].i = 0.;
  /* L130: */
  		}
  
  	    }
  L140:
  	    ;
  	}
      }
  
  /*     Right eigenvectors */
  
      if (compr) {
  	ieig = im + 1;
  
  /*        Main loop over eigenvalues */
  
  	for (je = *n; je >= 1; --je) {
  	    if (ilall) {
  		ilcomp = TRUE_;
  	    } else {
  		ilcomp = select[je];
  	    }
  	    if (ilcomp) {
  		--ieig;
  
  		i__1 = je + je * s_dim1;
  		i__2 = je + je * p_dim1;
  		if ((d__2 = s[i__1].r, abs(d__2)) + (d__3 = d_imag(&s[je + je 
  			* s_dim1]), abs(d__3)) <= safmin && (d__1 = p[i__2].r,
  			 abs(d__1)) <= safmin) {
  
  /*                 Singular matrix pencil -- return unit eigenvector */
  
  		    i__1 = *n;
  		    for (jr = 1; jr <= i__1; ++jr) {
  			i__2 = jr + ieig * vr_dim1;
  			vr[i__2].r = 0., vr[i__2].i = 0.;
  /* L150: */
  		    }
  		    i__1 = ieig + ieig * vr_dim1;
  		    vr[i__1].r = 1., vr[i__1].i = 0.;
  		    goto L250;
  		}
  
  /*              Non-singular eigenvalue: */
  /*              Compute coefficients  a  and  b  in */
  
  /*              ( a A - b B ) x  = 0 */
  
  /* Computing MAX */
  		i__1 = je + je * s_dim1;
  		i__2 = je + je * p_dim1;
  		d__4 = ((d__2 = s[i__1].r, abs(d__2)) + (d__3 = d_imag(&s[je 
  			+ je * s_dim1]), abs(d__3))) * ascale, d__5 = (d__1 = 
  			p[i__2].r, abs(d__1)) * bscale, d__4 = max(d__4,d__5);
  		temp = 1. / max(d__4,safmin);
  		i__1 = je + je * s_dim1;
  		z__2.r = temp * s[i__1].r, z__2.i = temp * s[i__1].i;
  		z__1.r = ascale * z__2.r, z__1.i = ascale * z__2.i;
  		salpha.r = z__1.r, salpha.i = z__1.i;
  		i__1 = je + je * p_dim1;
  		sbeta = temp * p[i__1].r * bscale;
  		acoeff = sbeta * ascale;
  		z__1.r = bscale * salpha.r, z__1.i = bscale * salpha.i;
  		bcoeff.r = z__1.r, bcoeff.i = z__1.i;
  
  /*              Scale to avoid underflow */
  
  		lsa = abs(sbeta) >= safmin && abs(acoeff) < small;
  		lsb = (d__1 = salpha.r, abs(d__1)) + (d__2 = d_imag(&salpha), 
  			abs(d__2)) >= safmin && (d__3 = bcoeff.r, abs(d__3)) 
  			+ (d__4 = d_imag(&bcoeff), abs(d__4)) < small;
  
  		scale = 1.;
  		if (lsa) {
  		    scale = small / abs(sbeta) * min(anorm,big);
  		}
  		if (lsb) {
  /* Computing MAX */
  		    d__3 = scale, d__4 = small / ((d__1 = salpha.r, abs(d__1))
  			     + (d__2 = d_imag(&salpha), abs(d__2))) * min(
  			    bnorm,big);
  		    scale = max(d__3,d__4);
  		}
  		if (lsa || lsb) {
  /* Computing MIN */
  /* Computing MAX */
  		    d__5 = 1., d__6 = abs(acoeff), d__5 = max(d__5,d__6), 
  			    d__6 = (d__1 = bcoeff.r, abs(d__1)) + (d__2 = 
  			    d_imag(&bcoeff), abs(d__2));
  		    d__3 = scale, d__4 = 1. / (safmin * max(d__5,d__6));
  		    scale = min(d__3,d__4);
  		    if (lsa) {
  			acoeff = ascale * (scale * sbeta);
  		    } else {
  			acoeff = scale * acoeff;
  		    }
  		    if (lsb) {
  			z__2.r = scale * salpha.r, z__2.i = scale * salpha.i;
  			z__1.r = bscale * z__2.r, z__1.i = bscale * z__2.i;
  			bcoeff.r = z__1.r, bcoeff.i = z__1.i;
  		    } else {
  			z__1.r = scale * bcoeff.r, z__1.i = scale * bcoeff.i;
  			bcoeff.r = z__1.r, bcoeff.i = z__1.i;
  		    }
  		}
  
  		acoefa = abs(acoeff);
  		bcoefa = (d__1 = bcoeff.r, abs(d__1)) + (d__2 = d_imag(&
  			bcoeff), abs(d__2));
  		xmax = 1.;
  		i__1 = *n;
  		for (jr = 1; jr <= i__1; ++jr) {
  		    i__2 = jr;
  		    work[i__2].r = 0., work[i__2].i = 0.;
  /* L160: */
  		}
  		i__1 = je;
  		work[i__1].r = 1., work[i__1].i = 0.;
  /* Computing MAX */
  		d__1 = ulp * acoefa * anorm, d__2 = ulp * bcoefa * bnorm, 
  			d__1 = max(d__1,d__2);
  		dmin__ = max(d__1,safmin);
  
  /*              Triangular solve of  (a A - b B) x = 0  (columnwise) */
  
  /*              WORK(1:j-1) contains sums w, */
  /*              WORK(j+1:JE) contains x */
  
  		i__1 = je - 1;
  		for (jr = 1; jr <= i__1; ++jr) {
  		    i__2 = jr;
  		    i__3 = jr + je * s_dim1;
  		    z__2.r = acoeff * s[i__3].r, z__2.i = acoeff * s[i__3].i;
  		    i__4 = jr + je * p_dim1;
  		    z__3.r = bcoeff.r * p[i__4].r - bcoeff.i * p[i__4].i, 
  			    z__3.i = bcoeff.r * p[i__4].i + bcoeff.i * p[i__4]
  			    .r;
  		    z__1.r = z__2.r - z__3.r, z__1.i = z__2.i - z__3.i;
  		    work[i__2].r = z__1.r, work[i__2].i = z__1.i;
  /* L170: */
  		}
  		i__1 = je;
  		work[i__1].r = 1., work[i__1].i = 0.;
  
  		for (j = je - 1; j >= 1; --j) {
  
  /*                 Form x(j) := - w(j) / d */
  /*                 with scaling and perturbation of the denominator */
  
  		    i__1 = j + j * s_dim1;
  		    z__2.r = acoeff * s[i__1].r, z__2.i = acoeff * s[i__1].i;
  		    i__2 = j + j * p_dim1;
  		    z__3.r = bcoeff.r * p[i__2].r - bcoeff.i * p[i__2].i, 
  			    z__3.i = bcoeff.r * p[i__2].i + bcoeff.i * p[i__2]
  			    .r;
  		    z__1.r = z__2.r - z__3.r, z__1.i = z__2.i - z__3.i;
  		    d__.r = z__1.r, d__.i = z__1.i;
  		    if ((d__1 = d__.r, abs(d__1)) + (d__2 = d_imag(&d__), abs(
  			    d__2)) <= dmin__) {
  			z__1.r = dmin__, z__1.i = 0.;
  			d__.r = z__1.r, d__.i = z__1.i;
  		    }
  
  		    if ((d__1 = d__.r, abs(d__1)) + (d__2 = d_imag(&d__), abs(
  			    d__2)) < 1.) {
  			i__1 = j;
  			if ((d__1 = work[i__1].r, abs(d__1)) + (d__2 = d_imag(
  				&work[j]), abs(d__2)) >= bignum * ((d__3 = 
  				d__.r, abs(d__3)) + (d__4 = d_imag(&d__), abs(
  				d__4)))) {
  			    i__1 = j;
  			    temp = 1. / ((d__1 = work[i__1].r, abs(d__1)) + (
  				    d__2 = d_imag(&work[j]), abs(d__2)));
  			    i__1 = je;
  			    for (jr = 1; jr <= i__1; ++jr) {
  				i__2 = jr;
  				i__3 = jr;
  				z__1.r = temp * work[i__3].r, z__1.i = temp * 
  					work[i__3].i;
  				work[i__2].r = z__1.r, work[i__2].i = z__1.i;
  /* L180: */
  			    }
  			}
  		    }
  
  		    i__1 = j;
  		    i__2 = j;
  		    z__2.r = -work[i__2].r, z__2.i = -work[i__2].i;
  		    zladiv_(&z__1, &z__2, &d__);
  		    work[i__1].r = z__1.r, work[i__1].i = z__1.i;
  
  		    if (j > 1) {
  
  /*                    w = w + x(j)*(a S(*,j) - b P(*,j) ) with scaling */
  
  			i__1 = j;
  			if ((d__1 = work[i__1].r, abs(d__1)) + (d__2 = d_imag(
  				&work[j]), abs(d__2)) > 1.) {
  			    i__1 = j;
  			    temp = 1. / ((d__1 = work[i__1].r, abs(d__1)) + (
  				    d__2 = d_imag(&work[j]), abs(d__2)));
  			    if (acoefa * rwork[j] + bcoefa * rwork[*n + j] >= 
  				    bignum * temp) {
  				i__1 = je;
  				for (jr = 1; jr <= i__1; ++jr) {
  				    i__2 = jr;
  				    i__3 = jr;
  				    z__1.r = temp * work[i__3].r, z__1.i = 
  					    temp * work[i__3].i;
  				    work[i__2].r = z__1.r, work[i__2].i = 
  					    z__1.i;
  /* L190: */
  				}
  			    }
  			}
  
  			i__1 = j;
  			z__1.r = acoeff * work[i__1].r, z__1.i = acoeff * 
  				work[i__1].i;
  			ca.r = z__1.r, ca.i = z__1.i;
  			i__1 = j;
  			z__1.r = bcoeff.r * work[i__1].r - bcoeff.i * work[
  				i__1].i, z__1.i = bcoeff.r * work[i__1].i + 
  				bcoeff.i * work[i__1].r;
  			cb.r = z__1.r, cb.i = z__1.i;
  			i__1 = j - 1;
  			for (jr = 1; jr <= i__1; ++jr) {
  			    i__2 = jr;
  			    i__3 = jr;
  			    i__4 = jr + j * s_dim1;
  			    z__3.r = ca.r * s[i__4].r - ca.i * s[i__4].i, 
  				    z__3.i = ca.r * s[i__4].i + ca.i * s[i__4]
  				    .r;
  			    z__2.r = work[i__3].r + z__3.r, z__2.i = work[
  				    i__3].i + z__3.i;
  			    i__5 = jr + j * p_dim1;
  			    z__4.r = cb.r * p[i__5].r - cb.i * p[i__5].i, 
  				    z__4.i = cb.r * p[i__5].i + cb.i * p[i__5]
  				    .r;
  			    z__1.r = z__2.r - z__4.r, z__1.i = z__2.i - 
  				    z__4.i;
  			    work[i__2].r = z__1.r, work[i__2].i = z__1.i;
  /* L200: */
  			}
  		    }
  /* L210: */
  		}
  
  /*              Back transform eigenvector if HOWMNY='B'. */
  
  		if (ilback) {
  		    zgemv_("N", n, &je, &c_b2, &vr[vr_offset], ldvr, &work[1], 
  			     &c__1, &c_b1, &work[*n + 1], &c__1);
  		    isrc = 2;
  		    iend = *n;
  		} else {
  		    isrc = 1;
  		    iend = je;
  		}
  
  /*              Copy and scale eigenvector into column of VR */
  
  		xmax = 0.;
  		i__1 = iend;
  		for (jr = 1; jr <= i__1; ++jr) {
  /* Computing MAX */
  		    i__2 = (isrc - 1) * *n + jr;
  		    d__3 = xmax, d__4 = (d__1 = work[i__2].r, abs(d__1)) + (
  			    d__2 = d_imag(&work[(isrc - 1) * *n + jr]), abs(
  			    d__2));
  		    xmax = max(d__3,d__4);
  /* L220: */
  		}
  
  		if (xmax > safmin) {
  		    temp = 1. / xmax;
  		    i__1 = iend;
  		    for (jr = 1; jr <= i__1; ++jr) {
  			i__2 = jr + ieig * vr_dim1;
  			i__3 = (isrc - 1) * *n + jr;
  			z__1.r = temp * work[i__3].r, z__1.i = temp * work[
  				i__3].i;
  			vr[i__2].r = z__1.r, vr[i__2].i = z__1.i;
  /* L230: */
  		    }
  		} else {
  		    iend = 0;
  		}
  
  		i__1 = *n;
  		for (jr = iend + 1; jr <= i__1; ++jr) {
  		    i__2 = jr + ieig * vr_dim1;
  		    vr[i__2].r = 0., vr[i__2].i = 0.;
  /* L240: */
  		}
  
  	    }
  L250:
  	    ;
  	}
      }
  
      return 0;
  
  /*     End of ZTGEVC */
  
  } /* ztgevc_ */
  