61 lines
1.3 KiB
C
61 lines
1.3 KiB
C
#include "clapack.h"
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doublereal dlapy2_(doublereal *x, doublereal *y)
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{
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/* System generated locals */
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doublereal ret_val, d__1;
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/* Builtin functions */
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double sqrt(doublereal);
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/* Local variables */
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doublereal w, z__, xabs, yabs;
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/* -- LAPACK auxiliary routine (version 3.1) -- */
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/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
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/* November 2006 */
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/* .. Scalar Arguments .. */
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/* .. */
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/* Purpose */
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/* ======= */
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/* DLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary */
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/* overflow. */
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/* Arguments */
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/* ========= */
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/* X (input) DOUBLE PRECISION */
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/* Y (input) DOUBLE PRECISION */
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/* X and Y specify the values x and y. */
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/* ===================================================================== */
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/* .. Parameters .. */
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/* .. */
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/* .. Local Scalars .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. Executable Statements .. */
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xabs = abs(*x);
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yabs = abs(*y);
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w = max(xabs,yabs);
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z__ = min(xabs,yabs);
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if (z__ == 0.) {
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ret_val = w;
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} else {
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/* Computing 2nd power */
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d__1 = z__ / w;
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ret_val = w * sqrt(d__1 * d__1 + 1.);
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}
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return ret_val;
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/* End of DLAPY2 */
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} /* dlapy2_ */
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