Update to 2.0.0 tree from current Fremantle build

[opencv] / 3rdparty / lapack / slartg.c

diff --git a/3rdparty/lapack/slartg.c b/3rdparty/lapack/slartg.c
new file mode 100644 (file)
index 0000000..c0a76dd
--- /dev/null
+++ b/3rdparty/lapack/slartg.c
@@ -0,0 +1,176 @@
+#include "clapack.h"
+
+/* Subroutine */ int slartg_(real *f, real *g, real *cs, real *sn, real *r__)
+{
+    /* System generated locals */
+    integer i__1;
+    real r__1, r__2;
+
+    /* Builtin functions */
+    double log(doublereal), pow_ri(real *, integer *), sqrt(doublereal);
+
+    /* Local variables */
+    integer i__;
+    real f1, g1, eps, scale;
+    integer count;
+    real safmn2, safmx2;
+    extern doublereal slamch_(char *);
+    real safmin;
+
+
+/*  -- LAPACK auxiliary routine (version 3.1) -- */
+/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/*     November 2006 */
+
+/*     .. Scalar Arguments .. */
+/*     .. */
+
+/*  Purpose */
+/*  ======= */
+
+/*  SLARTG generate a plane rotation so that */
+
+/*     [  CS  SN  ]  .  [ F ]  =  [ R ]   where CS**2 + SN**2 = 1. */
+/*     [ -SN  CS  ]     [ G ]     [ 0 ] */
+
+/*  This is a slower, more accurate version of the BLAS1 routine SROTG, */
+/*  with the following other differences: */
+/*     F and G are unchanged on return. */
+/*     If G=0, then CS=1 and SN=0. */
+/*     If F=0 and (G .ne. 0), then CS=0 and SN=1 without doing any */
+/*        floating point operations (saves work in SBDSQR when */
+/*        there are zeros on the diagonal). */
+
+/*  If F exceeds G in magnitude, CS will be positive. */
+
+/*  Arguments */
+/*  ========= */
+
+/*  F       (input) REAL */
+/*          The first component of vector to be rotated. */
+
+/*  G       (input) REAL */
+/*          The second component of vector to be rotated. */
+
+/*  CS      (output) REAL */
+/*          The cosine of the rotation. */
+
+/*  SN      (output) REAL */
+/*          The sine of the rotation. */
+
+/*  R       (output) REAL */
+/*          The nonzero component of the rotated vector. */
+
+/*  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 .. */
+/*     .. */
+/*     .. Save statement .. */
+/*     SAVE               FIRST, SAFMX2, SAFMIN, SAFMN2 */
+/*     .. */
+/*     .. Data statements .. */
+/*     DATA               FIRST / .TRUE. / */
+/*     .. */
+/*     .. Executable Statements .. */
+
+/*     IF( FIRST ) THEN */
+    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;
+/*        FIRST = .FALSE. */
+/*     END IF */
+    if (*g == 0.f) {
+       *cs = 1.f;
+       *sn = 0.f;
+       *r__ = *f;
+    } else if (*f == 0.f) {
+       *cs = 0.f;
+       *sn = 1.f;
+       *r__ = *g;
+    } else {
+       f1 = *f;
+       g1 = *g;
+/* Computing MAX */
+       r__1 = dabs(f1), r__2 = dabs(g1);
+       scale = dmax(r__1,r__2);
+       if (scale >= safmx2) {
+           count = 0;
+L10:
+           ++count;
+           f1 *= safmn2;
+           g1 *= safmn2;
+/* Computing MAX */
+           r__1 = dabs(f1), r__2 = dabs(g1);
+           scale = dmax(r__1,r__2);
+           if (scale >= safmx2) {
+               goto L10;
+           }
+/* Computing 2nd power */
+           r__1 = f1;
+/* Computing 2nd power */
+           r__2 = g1;
+           *r__ = sqrt(r__1 * r__1 + r__2 * r__2);
+           *cs = f1 / *r__;
+           *sn = g1 / *r__;
+           i__1 = count;
+           for (i__ = 1; i__ <= i__1; ++i__) {
+               *r__ *= safmx2;
+/* L20: */
+           }
+       } else if (scale <= safmn2) {
+           count = 0;
+L30:
+           ++count;
+           f1 *= safmx2;
+           g1 *= safmx2;
+/* Computing MAX */
+           r__1 = dabs(f1), r__2 = dabs(g1);
+           scale = dmax(r__1,r__2);
+           if (scale <= safmn2) {
+               goto L30;
+           }
+/* Computing 2nd power */
+           r__1 = f1;
+/* Computing 2nd power */
+           r__2 = g1;
+           *r__ = sqrt(r__1 * r__1 + r__2 * r__2);
+           *cs = f1 / *r__;
+           *sn = g1 / *r__;
+           i__1 = count;
+           for (i__ = 1; i__ <= i__1; ++i__) {
+               *r__ *= safmn2;
+/* L40: */
+           }
+       } else {
+/* Computing 2nd power */
+           r__1 = f1;
+/* Computing 2nd power */
+           r__2 = g1;
+           *r__ = sqrt(r__1 * r__1 + r__2 * r__2);
+           *cs = f1 / *r__;
+           *sn = g1 / *r__;
+       }
+       if (dabs(*f) > dabs(*g) && *cs < 0.f) {
+           *cs = -(*cs);
+           *sn = -(*sn);
+           *r__ = -(*r__);
+       }
+    }
+    return 0;
+
+/*     End of SLARTG */
+
+} /* slartg_ */