slapy2.f revision 7faaa9f3f0df9d23790277834d426c3d992ac3ba
17faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \brief \b SLAPY2 27faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 37faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* =========== DOCUMENTATION =========== 47faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 57faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* Online html documentation available at 67faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* http://www.netlib.org/lapack/explore-html/ 77faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 87faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \htmlonly 97faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> Download SLAPY2 + dependencies 107faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slapy2.f"> 117faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> [TGZ]</a> 127faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slapy2.f"> 137faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> [ZIP]</a> 147faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slapy2.f"> 157faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> [TXT]</a> 167faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \endhtmlonly 177faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 187faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* Definition: 197faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* =========== 207faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 217faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* REAL FUNCTION SLAPY2( X, Y ) 227faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 237faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. Scalar Arguments .. 247faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* REAL X, Y 257faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. 267faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 277faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 287faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \par Purpose: 297faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* ============= 307faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> 317faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \verbatim 327faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> 337faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> SLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary 347faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> overflow. 357faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \endverbatim 367faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 377faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* Arguments: 387faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* ========== 397faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 407faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \param[in] X 417faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \verbatim 427faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> X is REAL 437faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \endverbatim 447faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> 457faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \param[in] Y 467faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \verbatim 477faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> Y is REAL 487faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> X and Y specify the values x and y. 497faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \endverbatim 507faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 517faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* Authors: 527faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* ======== 537faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 547faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \author Univ. of Tennessee 557faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \author Univ. of California Berkeley 567faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \author Univ. of Colorado Denver 577faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \author NAG Ltd. 587faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 597faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \date November 2011 607faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 617faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez*> \ingroup auxOTHERauxiliary 627faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 637faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* ===================================================================== 647faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez REAL FUNCTION SLAPY2( X, Y ) 657faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 667faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* -- LAPACK auxiliary routine (version 3.4.0) -- 677faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* -- LAPACK is a software package provided by Univ. of Tennessee, -- 687faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 697faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* November 2011 707faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 717faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. Scalar Arguments .. 727faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez REAL X, Y 737faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. 747faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 757faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* ===================================================================== 767faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 777faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. Parameters .. 787faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez REAL ZERO 797faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez PARAMETER ( ZERO = 0.0E0 ) 807faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez REAL ONE 817faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez PARAMETER ( ONE = 1.0E0 ) 827faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. 837faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. Local Scalars .. 847faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez REAL W, XABS, YABS, Z 857faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. 867faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. Intrinsic Functions .. 877faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez INTRINSIC ABS, MAX, MIN, SQRT 887faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. 897faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* .. Executable Statements .. 907faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 917faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez XABS = ABS( X ) 927faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez YABS = ABS( Y ) 937faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez W = MAX( XABS, YABS ) 947faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez Z = MIN( XABS, YABS ) 957faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez IF( Z.EQ.ZERO ) THEN 967faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez SLAPY2 = W 977faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez ELSE 987faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez SLAPY2 = W*SQRT( ONE+( Z / W )**2 ) 997faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez END IF 1007faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez RETURN 1017faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 1027faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* End of SLAPY2 1037faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez* 1047faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez END 105