Update to 2.0.0 tree from current Fremantle build

[opencv] / 3rdparty / lapack / slasq6.c

diff --git a/3rdparty/lapack/slasq6.c b/3rdparty/lapack/slasq6.c
new file mode 100644 (file)
index 0000000..c9fbd35
--- /dev/null
+++ b/3rdparty/lapack/slasq6.c
@@ -0,0 +1,193 @@
+#include "clapack.h"
+
+/* Subroutine */ int slasq6_(integer *i0, integer *n0, real *z__, integer *pp, 
+        real *dmin__, real *dmin1, real *dmin2, real *dn, real *dnm1, real *
+       dnm2)
+{
+    /* System generated locals */
+    integer i__1;
+    real r__1, r__2;
+
+    /* Local variables */
+    real d__;
+    integer j4, j4p2;
+    real emin, temp;
+    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 .. */
+/*     .. */
+/*     .. Array Arguments .. */
+/*     .. */
+
+/*  Purpose */
+/*  ======= */
+
+/*  SLASQ6 computes one dqd (shift equal to zero) transform in */
+/*  ping-pong form, with protection against underflow and overflow. */
+
+/*  Arguments */
+/*  ========= */
+
+/*  I0    (input) INTEGER */
+/*        First index. */
+
+/*  N0    (input) INTEGER */
+/*        Last index. */
+
+/*  Z     (input) REAL array, dimension ( 4*N ) */
+/*        Z holds the qd array. EMIN is stored in Z(4*N0) to avoid */
+/*        an extra argument. */
+
+/*  PP    (input) INTEGER */
+/*        PP=0 for ping, PP=1 for pong. */
+
+/*  DMIN  (output) REAL */
+/*        Minimum value of d. */
+
+/*  DMIN1 (output) REAL */
+/*        Minimum value of d, excluding D( N0 ). */
+
+/*  DMIN2 (output) REAL */
+/*        Minimum value of d, excluding D( N0 ) and D( N0-1 ). */
+
+/*  DN    (output) REAL */
+/*        d(N0), the last value of d. */
+
+/*  DNM1  (output) REAL */
+/*        d(N0-1). */
+
+/*  DNM2  (output) REAL */
+/*        d(N0-2). */
+
+/*  ===================================================================== */
+
+/*     .. Parameter .. */
+/*     .. */
+/*     .. Local Scalars .. */
+/*     .. */
+/*     .. External Function .. */
+/*     .. */
+/*     .. Intrinsic Functions .. */
+/*     .. */
+/*     .. Executable Statements .. */
+
+    /* Parameter adjustments */
+    --z__;
+
+    /* Function Body */
+    if (*n0 - *i0 - 1 <= 0) {
+       return 0;
+    }
+
+    safmin = slamch_("Safe minimum");
+    j4 = (*i0 << 2) + *pp - 3;
+    emin = z__[j4 + 4];
+    d__ = z__[j4];
+    *dmin__ = d__;
+
+    if (*pp == 0) {
+       i__1 = *n0 - 3 << 2;
+       for (j4 = *i0 << 2; j4 <= i__1; j4 += 4) {
+           z__[j4 - 2] = d__ + z__[j4 - 1];
+           if (z__[j4 - 2] == 0.f) {
+               z__[j4] = 0.f;
+               d__ = z__[j4 + 1];
+               *dmin__ = d__;
+               emin = 0.f;
+           } else if (safmin * z__[j4 + 1] < z__[j4 - 2] && safmin * z__[j4 
+                   - 2] < z__[j4 + 1]) {
+               temp = z__[j4 + 1] / z__[j4 - 2];
+               z__[j4] = z__[j4 - 1] * temp;
+               d__ *= temp;
+           } else {
+               z__[j4] = z__[j4 + 1] * (z__[j4 - 1] / z__[j4 - 2]);
+               d__ = z__[j4 + 1] * (d__ / z__[j4 - 2]);
+           }
+           *dmin__ = dmin(*dmin__,d__);
+/* Computing MIN */
+           r__1 = emin, r__2 = z__[j4];
+           emin = dmin(r__1,r__2);
+/* L10: */
+       }
+    } else {
+       i__1 = *n0 - 3 << 2;
+       for (j4 = *i0 << 2; j4 <= i__1; j4 += 4) {
+           z__[j4 - 3] = d__ + z__[j4];
+           if (z__[j4 - 3] == 0.f) {
+               z__[j4 - 1] = 0.f;
+               d__ = z__[j4 + 2];
+               *dmin__ = d__;
+               emin = 0.f;
+           } else if (safmin * z__[j4 + 2] < z__[j4 - 3] && safmin * z__[j4 
+                   - 3] < z__[j4 + 2]) {
+               temp = z__[j4 + 2] / z__[j4 - 3];
+               z__[j4 - 1] = z__[j4] * temp;
+               d__ *= temp;
+           } else {
+               z__[j4 - 1] = z__[j4 + 2] * (z__[j4] / z__[j4 - 3]);
+               d__ = z__[j4 + 2] * (d__ / z__[j4 - 3]);
+           }
+           *dmin__ = dmin(*dmin__,d__);
+/* Computing MIN */
+           r__1 = emin, r__2 = z__[j4 - 1];
+           emin = dmin(r__1,r__2);
+/* L20: */
+       }
+    }
+
+/*     Unroll last two steps. */
+
+    *dnm2 = d__;
+    *dmin2 = *dmin__;
+    j4 = (*n0 - 2 << 2) - *pp;
+    j4p2 = j4 + (*pp << 1) - 1;
+    z__[j4 - 2] = *dnm2 + z__[j4p2];
+    if (z__[j4 - 2] == 0.f) {
+       z__[j4] = 0.f;
+       *dnm1 = z__[j4p2 + 2];
+       *dmin__ = *dnm1;
+       emin = 0.f;
+    } else if (safmin * z__[j4p2 + 2] < z__[j4 - 2] && safmin * z__[j4 - 2] < 
+           z__[j4p2 + 2]) {
+       temp = z__[j4p2 + 2] / z__[j4 - 2];
+       z__[j4] = z__[j4p2] * temp;
+       *dnm1 = *dnm2 * temp;
+    } else {
+       z__[j4] = z__[j4p2 + 2] * (z__[j4p2] / z__[j4 - 2]);
+       *dnm1 = z__[j4p2 + 2] * (*dnm2 / z__[j4 - 2]);
+    }
+    *dmin__ = dmin(*dmin__,*dnm1);
+
+    *dmin1 = *dmin__;
+    j4 += 4;
+    j4p2 = j4 + (*pp << 1) - 1;
+    z__[j4 - 2] = *dnm1 + z__[j4p2];
+    if (z__[j4 - 2] == 0.f) {
+       z__[j4] = 0.f;
+       *dn = z__[j4p2 + 2];
+       *dmin__ = *dn;
+       emin = 0.f;
+    } else if (safmin * z__[j4p2 + 2] < z__[j4 - 2] && safmin * z__[j4 - 2] < 
+           z__[j4p2 + 2]) {
+       temp = z__[j4p2 + 2] / z__[j4 - 2];
+       z__[j4] = z__[j4p2] * temp;
+       *dn = *dnm1 * temp;
+    } else {
+       z__[j4] = z__[j4p2 + 2] * (z__[j4p2] / z__[j4 - 2]);
+       *dn = z__[j4p2 + 2] * (*dnm1 / z__[j4 - 2]);
+    }
+    *dmin__ = dmin(*dmin__,*dn);
+
+    z__[j4 + 2] = *dn;
+    z__[(*n0 << 2) - *pp] = emin;
+    return 0;
+
+/*     End of SLASQ6 */
+
+} /* slasq6_ */