text: /*  -- translated by f2c (version 20100827).
     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"
  
  /* Table of constant values */
  
  static doublereal c_b4 = 1.;
  static doublereal c_b5 = 0.;
  static integer c__1 = 1;
  
  /* Subroutine */ int igraphdlarf_(char *side, integer *m, integer *n, doublereal *v,
  	 integer *incv, doublereal *tau, doublereal *c__, integer *ldc, 
  	doublereal *work)
  {
      /* System generated locals */
      integer c_dim1, c_offset;
      doublereal d__1;
  
      /* Local variables */
      integer i__;
      logical applyleft;
      extern /* Subroutine */ int igraphdger_(integer *, integer *, doublereal *, 
  	    doublereal *, integer *, doublereal *, integer *, doublereal *, 
  	    integer *);
      extern logical igraphlsame_(char *, char *);
      extern /* Subroutine */ int igraphdgemv_(char *, integer *, integer *, 
  	    doublereal *, doublereal *, integer *, doublereal *, integer *, 
  	    doublereal *, doublereal *, integer *);
      integer lastc, lastv;
      extern integer igraphiladlc_(integer *, integer *, doublereal *, integer *), 
  	    igraphiladlr_(integer *, integer *, doublereal *, integer *);
  
  
  /*  -- LAPACK auxiliary routine (version 3.3.1) --   
      -- LAPACK is a software package provided by Univ. of Tennessee,    --   
      -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--   
      -- April 2011                                                      --   
  
  
      Purpose   
      =======   
  
      DLARF applies a real elementary reflector H to a real m by n matrix   
      C, from either the left or the right. H is represented in the form   
  
            H = I - tau * v * v**T   
  
      where tau is a real scalar and v is a real vector.   
  
      If tau = 0, then H is taken to be the unit matrix.   
  
      Arguments   
      =========   
  
      SIDE    (input) CHARACTER*1   
              = 'L': form  H * C   
              = 'R': form  C * H   
  
      M       (input) INTEGER   
              The number of rows of the matrix C.   
  
      N       (input) INTEGER   
              The number of columns of the matrix C.   
  
      V       (input) DOUBLE PRECISION array, dimension   
                         (1 + (M-1)*abs(INCV)) if SIDE = 'L'   
                      or (1 + (N-1)*abs(INCV)) if SIDE = 'R'   
              The vector v in the representation of H. V is not used if   
              TAU = 0.   
  
      INCV    (input) INTEGER   
              The increment between elements of v. INCV <> 0.   
  
      TAU     (input) DOUBLE PRECISION   
              The value tau in the representation of H.   
  
      C       (input/output) DOUBLE PRECISION array, dimension (LDC,N)   
              On entry, the m by n matrix C.   
              On exit, C is overwritten by the matrix H * C if SIDE = 'L',   
              or C * H if SIDE = 'R'.   
  
      LDC     (input) INTEGER   
              The leading dimension of the array C. LDC >= max(1,M).   
  
      WORK    (workspace) DOUBLE PRECISION array, dimension   
                             (N) if SIDE = 'L'   
                          or (M) if SIDE = 'R'   
  
      =====================================================================   
  
  
         Parameter adjustments */
      --v;
      c_dim1 = *ldc;
      c_offset = 1 + c_dim1;
      c__ -= c_offset;
      --work;
  
      /* Function Body */
      applyleft = igraphlsame_(side, "L");
      lastv = 0;
      lastc = 0;
      if (*tau != 0.) {
  /*     Set up variables for scanning V.  LASTV begins pointing to the end   
         of V. */
  	if (applyleft) {
  	    lastv = *m;
  	} else {
  	    lastv = *n;
  	}
  	if (*incv > 0) {
  	    i__ = (lastv - 1) * *incv + 1;
  	} else {
  	    i__ = 1;
  	}
  /*     Look for the last non-zero row in V. */
  	while(lastv > 0 && v[i__] == 0.) {
  	    --lastv;
  	    i__ -= *incv;
  	}
  	if (applyleft) {
  /*     Scan for the last non-zero column in C(1:lastv,:). */
  	    lastc = igraphiladlc_(&lastv, n, &c__[c_offset], ldc);
  	} else {
  /*     Scan for the last non-zero row in C(:,1:lastv). */
  	    lastc = igraphiladlr_(m, &lastv, &c__[c_offset], ldc);
  	}
      }
  /*     Note that lastc.eq.0 renders the BLAS operations null; no special   
         case is needed at this level. */
      if (applyleft) {
  
  /*        Form  H * C */
  
  	if (lastv > 0) {
  
  /*           w(1:lastc,1) := C(1:lastv,1:lastc)**T * v(1:lastv,1) */
  
  	    igraphdgemv_("Transpose", &lastv, &lastc, &c_b4, &c__[c_offset], ldc, &
  		    v[1], incv, &c_b5, &work[1], &c__1);
  
  /*           C(1:lastv,1:lastc) := C(...) - v(1:lastv,1) * w(1:lastc,1)**T */
  
  	    d__1 = -(*tau);
  	    igraphdger_(&lastv, &lastc, &d__1, &v[1], incv, &work[1], &c__1, &c__[
  		    c_offset], ldc);
  	}
      } else {
  
  /*        Form  C * H */
  
  	if (lastv > 0) {
  
  /*           w(1:lastc,1) := C(1:lastc,1:lastv) * v(1:lastv,1) */
  
  	    igraphdgemv_("No transpose", &lastc, &lastv, &c_b4, &c__[c_offset], ldc,
  		     &v[1], incv, &c_b5, &work[1], &c__1);
  
  /*           C(1:lastc,1:lastv) := C(...) - w(1:lastc,1) * v(1:lastv,1)**T */
  
  	    d__1 = -(*tau);
  	    igraphdger_(&lastc, &lastv, &d__1, &work[1], &c__1, &v[1], incv, &c__[
  		    c_offset], ldc);
  	}
      }
      return 0;
  
  /*     End of DLARF */
  
  } /* igraphdlarf_ */
  
  