[PD] strange behaviour for look up table operation

[mick mengucci]

Hi lists,
we are making a new abstraction in Pd to convert from color space RGB to
CIE-Lch using a look up table. We map all the RGB triplets to an index of
the LUT that points to the correct conversion to CIE-Lch.

The problem is that when using [hsv2rgb] we get the same index number as
inputting directly the rgb triplet but different result from the look up
table.

How is that possible???

Here's a simplification of the patch to illustrate the problem (warning:
there are three tables with 1.65814e+07 values)

https://drive.google.com/file/d/0B6MlQyl-quuaYnEzQmtDOFFyckU

I hope somebody will have the patience to explain this very strange
behaviour of an apparently simple message to expression and look up table
operation. Maybe the size of the table and of the index is the reason for
it? We run Xubuntu and Pd 64bits.

Cheers

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