GRASS Programmer's Manual  6.4.2(2012)
c_stddev.c
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00001 #include <math.h>
00002 #include <grass/gis.h>
00003 #include <grass/stats.h>
00004 
00005 void c_stddev(DCELL * result, DCELL * values, int n, const void *closure)
00006 {
00007     DCELL var;
00008 
00009     c_var(&var, values, n, closure);
00010 
00011     if (G_is_d_null_value(&var))
00012         G_set_d_null_value(result, 1);
00013     else
00014         *result = sqrt(var);
00015 }
00016 
00017 void w_stddev(DCELL * result, DCELL(*values)[2], int n, const void *closure)
00018 {
00019     DCELL var;
00020 
00021     w_var(&var, values, n, closure);
00022 
00023     if (G_is_d_null_value(&var))
00024         G_set_d_null_value(result, 1);
00025     else
00026         *result = sqrt(var);
00027 }
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