Update to 2.0.0 tree from current Fremantle build

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

diff --git a/3rdparty/lapack/slabad.c b/3rdparty/lapack/slabad.c
new file mode 100644 (file)
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+++ b/3rdparty/lapack/slabad.c
@@ -0,0 +1,59 @@
+#include "clapack.h"
+
+/* Subroutine */ int slabad_(real *small, real *large)
+{
+    /* Builtin functions */
+    double r_lg10(real *), sqrt(doublereal);
+
+
+/*  -- LAPACK auxiliary routine (version 3.1) -- */
+/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/*     November 2006 */
+
+/*     .. Scalar Arguments .. */
+/*     .. */
+
+/*  Purpose */
+/*  ======= */
+
+/*  SLABAD takes as input the values computed by SLAMCH for underflow and */
+/*  overflow, and returns the square root of each of these values if the */
+/*  log of LARGE is sufficiently large.  This subroutine is intended to */
+/*  identify machines with a large exponent range, such as the Crays, and */
+/*  redefine the underflow and overflow limits to be the square roots of */
+/*  the values computed by SLAMCH.  This subroutine is needed because */
+/*  SLAMCH does not compensate for poor arithmetic in the upper half of */
+/*  the exponent range, as is found on a Cray. */
+
+/*  Arguments */
+/*  ========= */
+
+/*  SMALL   (input/output) REAL */
+/*          On entry, the underflow threshold as computed by SLAMCH. */
+/*          On exit, if LOG10(LARGE) is sufficiently large, the square */
+/*          root of SMALL, otherwise unchanged. */
+
+/*  LARGE   (input/output) REAL */
+/*          On entry, the overflow threshold as computed by SLAMCH. */
+/*          On exit, if LOG10(LARGE) is sufficiently large, the square */
+/*          root of LARGE, otherwise unchanged. */
+
+/*  ===================================================================== */
+
+/*     .. Intrinsic Functions .. */
+/*     .. */
+/*     .. Executable Statements .. */
+
+/*     If it looks like we're on a Cray, take the square root of */
+/*     SMALL and LARGE to avoid overflow and underflow problems. */
+
+    if (r_lg10(large) > 2e3f) {
+       *small = sqrt(*small);
+       *large = sqrt(*large);
+    }
+
+    return 0;
+
+/*     End of SLABAD */
+
+} /* slabad_ */