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12.3 weightpos

determine the mean weighted position of a group of objects

Synopsis

     #include <suplib/imagefcts.h>
     
     
     
double weightpos( void *objs, unsigned long n_tot, double tot_wt, size_t s_obj, double (*get_x)(const void *obj,double *x) );

Parameters

void *objs
list of objects whose mean position is to be determined
unsigned long n_tot
total number of objects to process
double tot_wt
total weight of objects. if zero, each object is assumed to have a weight of 1.
size_t s_obj
size of an object
double (*get_x)(const void *obj,double *x)
function which returns the position and weight of an object

Description

determine the mean weighted position of a group of objects. requires a user supplied function which extracts an object's position and weight. designed to be run over sub-groups of the list (for low memory situations). optimized for both weighted and unweighted (weight = 1) data.

Returns

It returns the mean weighted position of the group.

Author

Diab Jerius