Dear all,
After recent discussion of the math/calculus addon, I started playing
around with what could become a symbolic toolkit for J, which could in turn
serve as a backend for other projects, like future versions of the
math/calculus addon, explicit-to-tacit and vice versa, etc. It should thus
I've got a sparse csv with shape 1183748 2141. Where there is data, it
has usually tally 2, and probably never longer than 7.
My usual methods run out of memory, something like
([: <;._2 ,&',');._2 CR-.~LF_separated_csv
I tried sparse array to store index numbers of data, with data as a
preal
ps. remove "echo #" , it was nice when the loop runs just one pass.
The test file contained
id,x,xx
4,,t1
5,t2,t1
6,t1,
--
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Distinguish:
1. Notional function (f+)
2. Monadic application of a function (m+, conjugate)
3. Dyadic application of a function (d+, add)
Semantically, 2 and 3 are distinct from each other; but j puns them. (And 1
needs to be distinguished to bridge the gap with j semantics.)
The j -@:% is
See the 'prankb' and 'bslash' modifiers from my mailing list posting a few
months ago (or at
https://github.com/moon-chilled/j/blob/master/parallel/p.ijs). (I really
ought to polish these up into a library at some point.) The gist is, if you
have N cores, to slice up 'rows' into N chunks and
