VEC_$DAMAX_I Domain/OS VEC_$DAMAX_I
NAME
vec_$damax_i - find the maximum absolute value in a double-precision vec-
tor
SYNOPSIS (C)
#include <apollo/base.h>
#include <apollo/vec.h>
long int vec_$damax_i(
double *start_vec,
long int &start_inc,
long int &length,
double *result)
SYNOPSIS (Pascal)
%include '/sys/ins/base.ins.pas';
%include '/sys/ins/vec.ins.pas';
function vec_$damax_i(
in start_vec: univ vec_$double_vector;
in start_inc: integer32;
in length: integer32;
out result: double): integer32;
SYNOPSIS (FORTRAN)
%include '/sys/ins/base.ins.ftn'
%include '/sys/ins/vec.ins.ftn'
parameter (nvec = 10)
real*8 start_vec(nvec), result
integer*4 length, location
integer*4 start_inc
location = vec_$damax_i(start_vec, start_inc, length, result)
DESCRIPTION
Vec_$damax_i searches through length elements of start_vec, places the
greatest absolute-valued element in result, and returns the location of
the element with the greatest absolute value. By contrast, vec_$drmax_i
finds the element with greatest signed value. (The procedure vec_$dmax_i
is obsolete and should not be used.) In the case of a tie, vec_$damax_i
returns the index of the first maximum value found. vec_$damax differs
from vec_$amax in that the argument vector is double-precision floating-
point.
This call, like all vec_$ calls ending in _i, takes a set of extra stride
arguments, one for every vector argument. The stride arguments determine
which elements in the array are actually processed. For instance, if the
stride for a particular array is set to 3, every third element in the
array will be processed by the routine. The stride arguments need not be
identical. If all stride arguments are set to 1, this call behaves
exactly like the version without the _i in its name.
If the argument start_inc is not set to 1, the returned index is relative
to the stride; it does not necessarily correspond to the actual vector
index. For example, if start_inc is set to 5, and the third element
examined is the largest, this routine will return 3, even though the
actual index of the largest element is 11.
start_vec
The vector to be searched.
start_inc
The stride for start_vec.
length
The number of elements to be operated on; normally the same as the
number of elements in the vectors.
result
The value of the greatest element in start_vec.
NOTES
In C and Pascal, vec_$damax_i searches a row vector; in FORTRAN, it
searches a column vector.
SEE ALSO
vec_$rmax, vec_$rmin, vec_$amin, vec_$amax_i, vec_$amax, vec_$damax,
vec_$iamax, vec_$iamax_i, vec_$iamax16, vec_$iamax16_i.