** Reply Requested When Convenient ** Sorry for asking this. White-spaces are not accumulated. the file had to be changed into: 280 0 0 0.251 260 0 0 0.237 240 0 0 0.231 220 0 0 0.229 200 0 0 0.236 180 0 0 0.232 160 0 0 0.227 now read_matrix works. Robert