Abdelrahman Said
144 lines
3.3 KiB
C
144 lines
3.3 KiB
C
/* -- translated by f2c (version 20240504).
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You must link the resulting object file with libf2c:
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on Microsoft Windows system, link with libf2c.lib;
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on Linux or Unix systems, link with .../path/to/libf2c.a -lm
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or, if you install libf2c.a in a standard place, with -lf2c -lm
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-- in that order, at the end of the command line, as in
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cc *.o -lf2c -lm
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Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
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http://www.netlib.org/f2c/libf2c.zip
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*/
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#include "f2c.h"
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/* > \brief \b IDAMAX
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=========== DOCUMENTATION ===========
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Online html documentation available at
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http://www.netlib.org/lapack/explore-html/
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Definition:
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===========
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INTEGER FUNCTION IDAMAX(N,DX,INCX)
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INTEGER INCX,N
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DOUBLE PRECISION DX(*)
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> \par Purpose:
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=============
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>
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> \verbatim
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>
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> IDAMAX finds the index of the first element having maximum absolute value.
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> \endverbatim
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Arguments:
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==========
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> \param[in] N
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> \verbatim
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> N is INTEGER
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> number of elements in input vector(s)
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> \endverbatim
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>
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> \param[in] DX
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> \verbatim
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> DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
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> \endverbatim
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>
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> \param[in] INCX
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> \verbatim
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> INCX is INTEGER
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> storage spacing between elements of DX
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> \endverbatim
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Authors:
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========
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> \author Univ. of Tennessee
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> \author Univ. of California Berkeley
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> \author Univ. of Colorado Denver
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> \author NAG Ltd.
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> \ingroup iamax
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> \par Further Details:
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=====================
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>
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> \verbatim
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>
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> jack dongarra, linpack, 3/11/78.
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> modified 3/93 to return if incx .le. 0.
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> modified 12/3/93, array(1) declarations changed to array(*)
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> \endverbatim
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>
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===================================================================== */
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integer igraphidamax_(integer *n, doublereal *dx, integer *incx)
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{
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/* System generated locals */
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integer ret_val, i__1;
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doublereal d__1;
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/* Local variables */
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integer i__, ix;
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doublereal dmax__;
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/* -- Reference BLAS level1 routine --
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-- Reference BLAS is a software package provided by Univ. of Tennessee, --
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-- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
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=====================================================================
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Parameter adjustments */
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--dx;
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/* Function Body */
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ret_val = 0;
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if (*n < 1 || *incx <= 0) {
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return ret_val;
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}
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ret_val = 1;
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if (*n == 1) {
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return ret_val;
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}
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if (*incx == 1) {
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/* code for increment equal to 1 */
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dmax__ = abs(dx[1]);
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i__1 = *n;
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for (i__ = 2; i__ <= i__1; ++i__) {
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if ((d__1 = dx[i__], abs(d__1)) > dmax__) {
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ret_val = i__;
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dmax__ = (d__1 = dx[i__], abs(d__1));
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}
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}
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} else {
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/* code for increment not equal to 1 */
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ix = 1;
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dmax__ = abs(dx[1]);
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ix += *incx;
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i__1 = *n;
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for (i__ = 2; i__ <= i__1; ++i__) {
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if ((d__1 = dx[ix], abs(d__1)) > dmax__) {
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ret_val = i__;
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dmax__ = (d__1 = dx[ix], abs(d__1));
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}
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ix += *incx;
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}
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}
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return ret_val;
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/* End of IDAMAX */
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} /* igraphidamax_ */
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