[22] | 1 | *> \brief \b SLAPY2 |
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| 2 | * |
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| 3 | * =========== DOCUMENTATION =========== |
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| 4 | * |
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| 5 | * Online html documentation available at |
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| 6 | * http://www.netlib.org/lapack/explore-html/ |
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| 7 | * |
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| 8 | *> \htmlonly |
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| 9 | *> Download SLAPY2 + dependencies |
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| 10 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slapy2.f"> |
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| 11 | *> [TGZ]</a> |
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| 12 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slapy2.f"> |
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| 13 | *> [ZIP]</a> |
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| 14 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slapy2.f"> |
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| 15 | *> [TXT]</a> |
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| 16 | *> \endhtmlonly |
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| 17 | * |
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| 18 | * Definition: |
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| 19 | * =========== |
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| 20 | * |
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| 21 | * REAL FUNCTION SLAPY2( X, Y ) |
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| 22 | * |
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| 23 | * .. Scalar Arguments .. |
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| 24 | * REAL X, Y |
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| 25 | * .. |
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| 26 | * |
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| 27 | * |
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| 28 | *> \par Purpose: |
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| 29 | * ============= |
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| 30 | *> |
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| 31 | *> \verbatim |
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| 32 | *> |
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| 33 | *> SLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary |
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| 34 | *> overflow. |
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| 35 | *> \endverbatim |
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| 36 | * |
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| 37 | * Arguments: |
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| 38 | * ========== |
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| 39 | * |
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| 40 | *> \param[in] X |
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| 41 | *> \verbatim |
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| 42 | *> X is REAL |
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| 43 | *> \endverbatim |
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| 44 | *> |
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| 45 | *> \param[in] Y |
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| 46 | *> \verbatim |
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| 47 | *> Y is REAL |
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| 48 | *> X and Y specify the values x and y. |
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| 49 | *> \endverbatim |
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| 50 | * |
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| 51 | * Authors: |
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| 52 | * ======== |
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| 53 | * |
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| 54 | *> \author Univ. of Tennessee |
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| 55 | *> \author Univ. of California Berkeley |
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| 56 | *> \author Univ. of Colorado Denver |
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| 57 | *> \author NAG Ltd. |
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| 58 | * |
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| 59 | *> \date November 2011 |
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| 60 | * |
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| 61 | *> \ingroup auxOTHERauxiliary |
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| 62 | * |
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| 63 | * ===================================================================== |
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| 64 | REAL FUNCTION SLAPY2( X, Y ) |
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| 65 | * |
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| 66 | * -- LAPACK auxiliary routine (version 3.4.0) -- |
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| 67 | * -- LAPACK is a software package provided by Univ. of Tennessee, -- |
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| 68 | * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
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| 69 | * November 2011 |
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| 70 | * |
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| 71 | * .. Scalar Arguments .. |
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| 72 | REAL X, Y |
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| 73 | * .. |
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| 74 | * |
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| 75 | * ===================================================================== |
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| 76 | * |
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| 77 | * .. Parameters .. |
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| 78 | REAL ZERO |
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| 79 | PARAMETER ( ZERO = 0.0E0 ) |
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| 80 | REAL ONE |
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| 81 | PARAMETER ( ONE = 1.0E0 ) |
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| 82 | * .. |
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| 83 | * .. Local Scalars .. |
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| 84 | REAL W, XABS, YABS, Z |
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| 85 | * .. |
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| 86 | * .. Intrinsic Functions .. |
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| 87 | INTRINSIC ABS, MAX, MIN, SQRT |
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| 88 | * .. |
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| 89 | * .. Executable Statements .. |
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| 90 | * |
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| 91 | XABS = ABS( X ) |
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| 92 | YABS = ABS( Y ) |
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| 93 | W = MAX( XABS, YABS ) |
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| 94 | Z = MIN( XABS, YABS ) |
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| 95 | IF( Z.EQ.ZERO ) THEN |
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| 96 | SLAPY2 = W |
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| 97 | ELSE |
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| 98 | SLAPY2 = W*SQRT( ONE+( Z / W )**2 ) |
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| 99 | END IF |
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| 100 | RETURN |
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| 101 | * |
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| 102 | * End of SLAPY2 |
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| 103 | * |
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| 104 | END |
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