Encoding binary categories & empty input

[breznak]

In DateTime encoder #462 I noticed a field weekend is encoded as a Category (with scalar encoder).

Weekend is a binary field : T/F.
We use scalar encoder for categories, with radius=1(no overlap).
Say w=5.
T = [1111100000]
F = [0000011111]

This encoding makes sense for number of categories >2, but for binary cats, I'd prefer
T = [11111]
F = [00000]

Do we want to add such hack to Scalar?

[breznak]

CC @ctrl-z-9000-times

[breznak]

..ok, probably not worth it, as scalar is more an example encoder. For real problems, one should use RDSE (which can encode categories the same way), and there this should not be applicable.

[ctrl-z-9000-times]

T = [11111]
F = [00000]

This does not have a constant sparsity, and I think that the spatial pool might have trouble recognizing "F"

If you want to do this anyways then there is a simple hack for this:
SDR({ w }).randomize( float( data == "T" ) )

[breznak]

This does not have a constant sparsity,

this is a good point. And with above "solved by RDSE", probably not worth hacking.

and I think that the spatial pool might have trouble recognizing "F"

this is a good point, an old issue. I think SP should be able to recognize and act on "no input" as some input. I'll make a separate issue for this. A solution on my mind, have a const random SDR that is encoded each time {} is on SP.compute()