Two reports:
(1) performance of {:: differs significantly between mapped and ordinary
variables
(2) (<3;3){ X=.10 10$a: crashes the system if X is a mapped variable
NB. Issue 1 =============================================
require'jmf'
jdatafn=: jpath '~temp\jdata.jmf'
createjmf_jmf_ jdatafn;100e6
map_jmf_ 'mapped';jdatafn
mapped=:1e6$a: NB variable mapped to file
ordinary=:1e6$a: NB. ordinary variable
NB. timings of { are consistent between mapped and ordinary variables
0j10":(10) 6!:2'10{mapped'
0.0000061740
0j10":(10) 6!:2'10{ordinary'
0.0000064254
NB. but for {:: the timings are inconsistent.
0j10":(10) 6!:2'10{::mapped'
0.0238224970
0j10":(10) 6!:2'10{::ordinary'
0.0000092749
NB. Issue 2 =============================================
mapped =. 10 10$a:
The following causes J to crash.
(<3;3){mapped
David
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