printf("%i,%i[%i] %g -> %i + %g\n", x, y, i, p, (int)d, e);

----
perfs for pipi random:256x256 --wrap --median X:

X = 1  X = 2  X = 3  X = 4  X = 5   X = 6
0.133  0.458  1.288  3.066  6.370  11.931
0.127  0.435  1.289  3.062  6.355  11.944
0.128  0.445  1.282  3.053  6.354  11.916
0.120  0.432  1.264  3.089  6.362  11.938
0.120  0.436  1.292  3.048  6.366  11.911

after switching to qsort:
X = 1  X = 2  X = 3  X = 4  X = 5  X = 6  X = 7   X = 8
0.257  0.733  1.519  2.704  4.192  6.143  8.193  10.880
0.241  0.731  1.541  2.709  4.179  6.172  8.194  10.889
0.243  0.736  1.540  2.728  4.174  6.123  8.221  10.824
0.241  0.725  1.530  2.706  4.161  6.135  8.288  10.791
0.241  0.725  1.528  2.733  4.168  6.142  8.208  10.805

my qsort:
X = 1  X = 2  X = 3  X = 4  X = 5  X = 6  X = 7   X = 8
0.161  0.438  0.974  1.856  3.155  5.041  7.637  11.191
0.157  0.427  0.971  1.840  3.138  5.047  7.641  11.170
0.156  0.438  0.972  1.845  3.146  5.040  7.650  11.165
0.164  0.437  0.969  1.839  3.150  5.025  7.647  11.119
0.164  0.450  0.968  1.834  3.152  5.043  7.651  11.097