/*
---------------------------------------------------
initialize the object, storage freed if repeat call
created -- 95dec17, cca
---------------------------------------------------
*/
void
Coords_init (
Coords *coords,
int type,
int ndim,
int ncoor
) {
/*
---------------
check the input
---------------
*/
if ( coords == NULL
|| !(type == COORDS_BY_TUPLE || type == COORDS_BY_COORD)
|| ndim < 1 || ncoor <= 0 ) {
fprintf(stderr, "\n fatal error in Coords_init(%p,%d,%d,%d)"
"\n bad input\n", coords, type, ndim, ncoor) ;
exit(-1) ;
}
/*
--------------
clear the data
--------------
*/
Coords_clearData(coords) ;
/*
-------------------
set the data fields
-------------------
*/
coords->type = type ;
coords->ndim = ndim ;
coords->ncoor = ncoor ;
coords->coors = FVinit(ndim*ncoor, 0.0) ;
return ; }
/*
-------------------------------------------------------
purpose -- given the pair of arrays (x1[],y1[]),
create a pair of arrays (x2[],y2[]) whose
entries are pairwise chosen from (x1[],y1[])
and whose distribution is an approximation.
return value -- the size of the (x2[],y2[]) arrays
created -- 95sep22, cca
-------------------------------------------------------
*/
int
FVcompress (
int size1,
float x1[],
float y1[],
int size2,
float x2[],
float y2[]
) {
float delta, dx, dy, path, totalPath ;
float *ds ;
int i, j ;
/*
--------------------
check the input data
--------------------
*/
if ( size1 <= 0 || size2 <= 0 ) {
return(0) ;
} else if ( x1 == NULL || y1 == NULL || x2 == NULL || y2 == NULL ) {
fprintf(stderr, "\n fatal error in FVcompress, invalid data"
"\n size1 = %d, x1 = %p, y1 = %p"
"\n size2 = %d, x2 = %p, y2 = %p",
size1, x1, y1, size2, x2, y2) ;
exit(-1) ;
}
/*
----------------------------------------
compute the path length and its segments
----------------------------------------
*/
ds = FVinit(size1, 0.0) ;
for ( j = 1 ; j < size1 ; j++ ) {
dx = x1[j] - x1[j-1] ;
dy = y1[j] - y1[j-1] ;
ds[j-1] = sqrt(dx*dx + dy*dy) ;
}
totalPath = FVsum(size1, ds) ;
delta = totalPath / (size2-2) ;
#if MYDEBUG > 0
fprintf(stdout, "\n totalPath = %12.4e, delta = %12.4e, ds",
totalPath, delta) ;
FVfprintf(stdout, size1, ds) ;
#endif
/*
---------------------
fill the second array
---------------------
*/
i = 0 ;
x2[i] = x1[i] ;
y2[i] = y1[i] ;
i++ ;
path = 0. ;
for ( j = 1 ; j < size1 - 1 ; j++ ) {
path += ds[j-1] ;
#if MYDEBUG > 0
fprintf(stdout, "\n j %d, path %12.4e", j, path) ;
#endif
if ( path >= delta ) {
#if MYDEBUG > 0
fprintf(stdout, ", accepted") ;
#endif
x2[i] = x1[j] ;
y2[i] = y1[j] ;
i++ ;
path = 0. ;
}
}
x2[i] = x1[size1-1] ;
y2[i] = y1[size1-1] ;
i++ ;
/*
------------------------
free the working storage
------------------------
*/
FVfree(ds) ;
return(i) ; }
