B Jonas reported that ~. is inconsistent with the definition:
tb=. 1+2e_14*i:3
~: tb
1 0 0 0 0 0 0
=tb
1 1 1 0 0 0 0
You could fix that in the docs. But the problem is much more serious:
the partitioning induced by ~. does not match that induced by u/. .
That these be identical is a canon of J, relied on by code whose name is
legion.
~. tb
1
tb </. tb
+-----+-+-+-+-+
|1 1 1|1|1|1|1|
+-----+-+-+-+-+
What!? Only 1 unique item, but 4 partitions???
The special code for #/. shares the problem:
#/.~ tb
3
only 3 items from a list of 7!
The interpreter itself relies on the equivalence, and is let down:
(#,{.)/.~ tb
|length error
| (#,{.)/.~tb
there shouldn't be any error.
IMO this will be the first bug for us to fix, if Jsoftware ever creates
a proper open-source setup that allows user contributions to get into
the official release.
Henry Rich
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