Artifact 2a37e11e5a281ae9e79c757aa76afb418ebe718a:

• File operator/stats-float.crimp — part of check-in [fcddf7d438] at 2011-04-22 17:05:22 on branch trunk — Added macros for area and volume calculations, with proper casting to avoid the 4-gpixel barrier. Updated various places to use these macros now. Note that Tcl_Objs are still limited to 4G, mostly. (user: andreask size: 1764) [more...]

stats_float
Tcl_Obj* imageObj

crimp_image* image;
Tcl_Obj* result;
Tcl_Obj* cname;
Tcl_Obj* cdata;

size_t n;
int x, y, w, h;
double min, max, var, stddev, mean, median, middle, sum, sumsq;

crimp_input (imageObj, image, float);

w = image->w;
h = image->h;
n = crimp_image_area (image);

/* 
 * Scan image
 */

sum = sumsq = 0;
min = max = FLOATP (image, 0, 0);

for (y = 0; y < h; y++) {
    for (x = 0; x < w; x++) {
	double val = FLOATP (image, x, y);

	sum   += val;
	sumsq += val*val;
	min = MIN (min, val);
	max = MAX (max, val);
    }
}

mean   = sum / n;
middle = (min + max)/2;
var    = sumsq/n - mean*mean;
stddev = sqrt (var);

/*
 * Fill the dictonary.
 * NOTES:
 * (1) No histogram, we currently have no efficient way of computing that for floats.
 * (2) No median either, as this is based on the histogram.
 *
 * FUTURE: Some way of sharing the string Tcl_Obj* for the fixed keys.
 */

cdata = Tcl_NewDictObj ();
Tcl_DictObjPut (NULL, cdata, Tcl_NewStringObj ("min",      -1), Tcl_NewDoubleObj (min));
Tcl_DictObjPut (NULL, cdata, Tcl_NewStringObj ("max",      -1), Tcl_NewDoubleObj (max));
Tcl_DictObjPut (NULL, cdata, Tcl_NewStringObj ("mean",     -1), Tcl_NewDoubleObj (mean));
Tcl_DictObjPut (NULL, cdata, Tcl_NewStringObj ("middle",   -1), Tcl_NewDoubleObj (middle));
Tcl_DictObjPut (NULL, cdata, Tcl_NewStringObj ("variance", -1), Tcl_NewDoubleObj (var));
Tcl_DictObjPut (NULL, cdata, Tcl_NewStringObj ("stddev",   -1), Tcl_NewDoubleObj (stddev));

result = Tcl_NewDictObj ();
Tcl_DictObjPut (NULL, result, Tcl_NewStringObj (image->itype->cname[0],-1), cdata);

Tcl_SetObjResult (interp, result);
return TCL_OK;


/* vim: set sts=4 sw=4 tw=80 et ft=c: */
/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */