*> \brief \b DZSUM1 forms the 1-norm of the complex vector using the true absolute value. * * =========== DOCUMENTATION =========== * * Online html documentation available at * http://www.netlib.org/lapack/explore-html/ * *> \htmlonly *> Download DZSUM1 + dependencies *> *> [TGZ] *> *> [ZIP] *> *> [TXT] *> \endhtmlonly * * Definition: * =========== * * DOUBLE PRECISION FUNCTION DZSUM1( N, CX, INCX ) * * .. Scalar Arguments .. * INTEGER INCX, N * .. * .. Array Arguments .. * COMPLEX*16 CX( * ) * .. * * *> \par Purpose: * ============= *> *> \verbatim *> *> DZSUM1 takes the sum of the absolute values of a complex *> vector and returns a double precision result. *> *> Based on DZASUM from the Level 1 BLAS. *> The change is to use the 'genuine' absolute value. *> \endverbatim * * Arguments: * ========== * *> \param[in] N *> \verbatim *> N is INTEGER *> The number of elements in the vector CX. *> \endverbatim *> *> \param[in] CX *> \verbatim *> CX is COMPLEX*16 array, dimension (N) *> The vector whose elements will be summed. *> \endverbatim *> *> \param[in] INCX *> \verbatim *> INCX is INTEGER *> The spacing between successive values of CX. INCX > 0. *> \endverbatim * * Authors: * ======== * *> \author Univ. of Tennessee *> \author Univ. of California Berkeley *> \author Univ. of Colorado Denver *> \author NAG Ltd. * *> \date December 2016 * *> \ingroup complex16OTHERauxiliary * *> \par Contributors: * ================== *> *> Nick Higham for use with ZLACON. * * ===================================================================== DOUBLE PRECISION FUNCTION DZSUM1( N, CX, INCX ) * * -- LAPACK auxiliary routine (version 3.7.0) -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- * December 2016 * * .. Scalar Arguments .. INTEGER INCX, N * .. * .. Array Arguments .. COMPLEX*16 CX( * ) * .. * * ===================================================================== * * .. Local Scalars .. INTEGER I, NINCX DOUBLE PRECISION STEMP * .. * .. Intrinsic Functions .. INTRINSIC ABS * .. * .. Executable Statements .. * DZSUM1 = 0.0D0 STEMP = 0.0D0 IF( N.LE.0 ) $ RETURN IF( INCX.EQ.1 ) $ GO TO 20 * * CODE FOR INCREMENT NOT EQUAL TO 1 * NINCX = N*INCX DO 10 I = 1, NINCX, INCX * * NEXT LINE MODIFIED. * STEMP = STEMP + ABS( CX( I ) ) 10 CONTINUE DZSUM1 = STEMP RETURN * * CODE FOR INCREMENT EQUAL TO 1 * 20 CONTINUE DO 30 I = 1, N * * NEXT LINE MODIFIED. * STEMP = STEMP + ABS( CX( I ) ) 30 CONTINUE DZSUM1 = STEMP RETURN * * End of DZSUM1 * END