Annotation of rpl/lapack/lapack/dzsum1.f, revision 1.8
1.8 ! bertrand 1: *> \brief \b DZSUM1
! 2: *
! 3: * =========== DOCUMENTATION ===========
! 4: *
! 5: * Online html documentation available at
! 6: * http://www.netlib.org/lapack/explore-html/
! 7: *
! 8: *> \htmlonly
! 9: *> Download DZSUM1 + dependencies
! 10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dzsum1.f">
! 11: *> [TGZ]</a>
! 12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dzsum1.f">
! 13: *> [ZIP]</a>
! 14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dzsum1.f">
! 15: *> [TXT]</a>
! 16: *> \endhtmlonly
! 17: *
! 18: * Definition:
! 19: * ===========
! 20: *
! 21: * DOUBLE PRECISION FUNCTION DZSUM1( N, CX, INCX )
! 22: *
! 23: * .. Scalar Arguments ..
! 24: * INTEGER INCX, N
! 25: * ..
! 26: * .. Array Arguments ..
! 27: * COMPLEX*16 CX( * )
! 28: * ..
! 29: *
! 30: *
! 31: *> \par Purpose:
! 32: * =============
! 33: *>
! 34: *> \verbatim
! 35: *>
! 36: *> DZSUM1 takes the sum of the absolute values of a complex
! 37: *> vector and returns a double precision result.
! 38: *>
! 39: *> Based on DZASUM from the Level 1 BLAS.
! 40: *> The change is to use the 'genuine' absolute value.
! 41: *> \endverbatim
! 42: *
! 43: * Arguments:
! 44: * ==========
! 45: *
! 46: *> \param[in] N
! 47: *> \verbatim
! 48: *> N is INTEGER
! 49: *> The number of elements in the vector CX.
! 50: *> \endverbatim
! 51: *>
! 52: *> \param[in] CX
! 53: *> \verbatim
! 54: *> CX is COMPLEX*16 array, dimension (N)
! 55: *> The vector whose elements will be summed.
! 56: *> \endverbatim
! 57: *>
! 58: *> \param[in] INCX
! 59: *> \verbatim
! 60: *> INCX is INTEGER
! 61: *> The spacing between successive values of CX. INCX > 0.
! 62: *> \endverbatim
! 63: *
! 64: * Authors:
! 65: * ========
! 66: *
! 67: *> \author Univ. of Tennessee
! 68: *> \author Univ. of California Berkeley
! 69: *> \author Univ. of Colorado Denver
! 70: *> \author NAG Ltd.
! 71: *
! 72: *> \date November 2011
! 73: *
! 74: *> \ingroup complex16OTHERauxiliary
! 75: *
! 76: *> \par Contributors:
! 77: * ==================
! 78: *>
! 79: *> Nick Higham for use with ZLACON.
! 80: *
! 81: * =====================================================================
1.1 bertrand 82: DOUBLE PRECISION FUNCTION DZSUM1( N, CX, INCX )
83: *
1.8 ! bertrand 84: * -- LAPACK auxiliary routine (version 3.4.0) --
1.1 bertrand 85: * -- LAPACK is a software package provided by Univ. of Tennessee, --
86: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.8 ! bertrand 87: * November 2011
1.1 bertrand 88: *
89: * .. Scalar Arguments ..
90: INTEGER INCX, N
91: * ..
92: * .. Array Arguments ..
93: COMPLEX*16 CX( * )
94: * ..
95: *
96: * =====================================================================
97: *
98: * .. Local Scalars ..
99: INTEGER I, NINCX
100: DOUBLE PRECISION STEMP
101: * ..
102: * .. Intrinsic Functions ..
103: INTRINSIC ABS
104: * ..
105: * .. Executable Statements ..
106: *
107: DZSUM1 = 0.0D0
108: STEMP = 0.0D0
109: IF( N.LE.0 )
110: $ RETURN
111: IF( INCX.EQ.1 )
112: $ GO TO 20
113: *
114: * CODE FOR INCREMENT NOT EQUAL TO 1
115: *
116: NINCX = N*INCX
117: DO 10 I = 1, NINCX, INCX
118: *
119: * NEXT LINE MODIFIED.
120: *
121: STEMP = STEMP + ABS( CX( I ) )
122: 10 CONTINUE
123: DZSUM1 = STEMP
124: RETURN
125: *
126: * CODE FOR INCREMENT EQUAL TO 1
127: *
128: 20 CONTINUE
129: DO 30 I = 1, N
130: *
131: * NEXT LINE MODIFIED.
132: *
133: STEMP = STEMP + ABS( CX( I ) )
134: 30 CONTINUE
135: DZSUM1 = STEMP
136: RETURN
137: *
138: * End of DZSUM1
139: *
140: END
CVSweb interface <joel.bertrand@systella.fr>