The definition for the Chi squared Cumulative Distribution Function given in the essay http://www.jsoftware.com/jwiki/Essays/Chi%20Squared%20CDF and in the distribution.ijs script of the stats/base addon, seems to be unstable for large values. For example:
9 chisqcdf 5 10 30 100 1000 1400 1420 1470 1471 0.16569174 0.64951479 0.99956128 1 1 1 0 0 0 9 chisqcdf 1472 |NaN error: chisqcdf | (1 H.(1+x)%x&((*^)*(^-)~))y Also: 100 200 400 600 3545 chisqcdf 3 4.8195188e_57 9.8668347e_142 0 0 0 3546 chisqcdf 3 |NaN error: chisqcdf | 3546 chisqcdf 3 Has anyone come up with more robust implementations? ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
