RuntimeWarning: divide by zero

[SteveKing]

The script appears to work (it generates an output file with the expected color differences) but I get a divide by zero warning and, with the --invert flag, an "invalid value encountered in power" warning.

Good work on this, BTW! I think perceptual color space is fascinating.

colorprofiles.zip

macabre:~/tmp/iterm_schemer$ python3 -m iterm_schemer irblack.itermcolors OutputLight.itermcolors --src-bg dark --dst-bg light --invert
/usr/local/lib/python3.6/site-packages/colour/appearance/ciecam02.py:1358: RuntimeWarning: divide by zero encountered in double_scalars
  P_1 = ((50000 / 13) * N_c * N_cb * e_t) / t
Ansi 0 Color       [  0   0   0] → [  0   0   0]
Ansi 1 Color       [252 111  92] → [255 118  91]
Ansi 2 Color       [174 250  58] → [169 255   0]
Ansi 3 Color       [255 253 173] → [255 255 146]
Ansi 4 Color       [150 201 255] → [153 209 255]
Ansi 5 Color       [250 115 255] → [255 123 255]
Ansi 6 Color       [197 196 255] → [202 201 255]
Ansi 7 Color       [237 237 237] → [244 244 244]
Ansi 8 Color       [123 123 123] → [160 160 160]
Ansi 9 Color       [253 182 175] → [255 187 178]
Ansi 10 Color      [209 252 162] → [203 255 132]
Ansi 11 Color      [255 253 197] → [255 255 178]
Ansi 12 Color      [181 218 255] → [179 222 255]
Ansi 13 Color      [251 156 255] → [255 157 255]
Ansi 14 Color      [222 222 255] → [222 222 255]
Ansi 15 Color      [254 255 254] → [254 255 254]
Foreground Color   [237 237 237] → [ 24  24  24]
Background Color   [  0   0   0] → [255 255 255]
Bold Color         [255 255 255] → [  0   0   0]
/usr/local/lib/python3.6/site-packages/colour/appearance/ciecam02.py:714: RuntimeWarning: invalid value encountered in power
  RGB_c = ((((400 * (F_L[..., np.newaxis] * RGB / 100) ** 0.42) /
/usr/local/lib/python3.6/site-packages/colour/appearance/ciecam02.py:715: RuntimeWarning: invalid value encountered in power
  (27.13 + (F_L[..., np.newaxis] * RGB / 100) ** 0.42))) + 0.1)
Cursor Color       [255 180 115] → [ 94  25   0]
Cursor Text Color  [237 237 237] → [ 24  24  24]
macabre:~/tmp/iterm_schemer$

[crowsonkb]

It looks like the 'invalid value encountered in power' warnings are due to colour-science not checking or and handling negative values in one place. I'm working on a pull request for it: colour-science/colour#326. The divide by zero warnings are due to colour-science not testing for divide by zero, and I am still working on it.

[crowsonkb]

Pull request colour-science/colour#327, fixing the divide by zero issue, submitted upstream. I also created a special branch in my colour-science fork for iterm_schemer, and if you reinstall it with this URL git+https://github.com/crowsonkb/colour@iterm_schemer it has these two pull requests merged already.