For me, this works with the latest change about the compression algorithm:

```
$ gmic input 32,32,32,3,[x,y,z]*8-127 +compress_clut 0.5,0.1 +decompress_clut. 32
```

Command `input`

creates the out-of-gammut CLUT, then I compress it with quite high fidelity parameters, then decompress it, and it seems I get two similar CLUTs.

```
[gmic]-0./ Start G'MIC interpreter.
[gmic]-0./ Input image at position 0, with values '[x,y,z]*8-127' (1 image 32x32x32x3).
[gmic]-1./ Compress color LUT [0] as a set of colored keypoints, with maximum error 0.5, average error 0.1, 2048 maximum keypoints, DeltaE_2000 metric and srgb colorspace for reconstruction.
* Process CLUT '[image of '[x,y,z]*8-127']' (32x32x32).
> Add [#22] Max_Err = 0.403142, Avg_Err = 0.0885882
> Rem [#16/17] Max_Err = 0.956023, Avg_Err = 0.118862
[gmic]-1./ Decompress colored keypoint [1] into 32x32x32 CLUTs, using srgb colorspace for reconstruction.
[gmic]-3./ Display images [0,1,2] = '[image of '[x,y,z]*8-127'], image_of_x,y,z*8-127_c1, image_of_x,y,z*8-127_c2'.
[0] = '[image of '[x,y,z]*8-127']':
size = (32,32,32,3) [384 Kio of floats].
data = (-127,-119,-111,-103,-95,-87,-79,-71,-63,-55,-47,-39,(...),121,121,121,121,121,121,121,121,121,121,121,121).
min = -127, max = 121, mean = -3, std = 73.8651, coords_min = (0,0,0,0), coords_max = (31,0,0,0).
[1] = 'image_of_x,y,z*8-127_c1':
size = (1,18,1,6) [432 b of floats].
data = (0;0;0;0;24.6774;41.129;57.5806;82.2581;98.7097;139.839;172.742;172.742;(...),-47;-95;49;25;-103;1;-103;89;-127;121;-127;121).
min = -127, max = 255, mean = 63.4519, std = 121.061, coords_min = (0,0,0,3), coords_max = (0,14,0,0).
[2] = 'image_of_x,y,z*8-127_c2':
size = (32,32,32,3) [384 Kio of floats].
data = (-127,-118.653,-110.382,-102.172,-94.0126,-85.8976,-77.8207,-69.7767,-61.7611,-53.77,-45.7999,-37.8478,(...),121.345,121.336,121.319,121.292,121.256,121.209,121.153,121.09,121.028,120.978,120.959,121).
min = -127.958, max = 121.644, mean = -2.91478, std = 73.6164, coords_min = (18,31,0,2), coords_max = (0,19,31,2).
[gmic]-3./ End G'MIC interpreter.
```

(look at stats of images [0] and [1], which are basically the same).