Something has gone terribly awry with 2 ~:/\ q.  I'll look into it.

Henry Rich

On 1/15/2020 2:30 AM, Joey K Tuttle wrote:
I was fiddling with patterns in the first 10e9 digits of Pi this evening and 
was surprised by a timing.

Rather than what I was fooling with, I put it into a smaller easily reproduced 
example, to wit -

MBpro-3:JKTststs jkt$ ja
    JVERSION
Engine: j807/j64/darwin
Release-e: commercial/2019-11-04T12:57:58
Library: 8.07.26
Platform: Darwin 64
Installer: J807 install
InstallPath: /applications/j64-807
Contact: www.jsoftware.com
    20?.@$ 2
0 1 0 1 1 0 0 1 1 1 0 0 0 0 1 0 0 0 1 0
    rl
[: #;.1~ 1 , 2 ~:/\ ]
    rl 20?.@$ 2
1 1 1 2 2 3 4 1 3 1 1
    q=. (50e6 ?.@$ 10){'0123456789'
    timex 'z=. rl q'
1.720735 649991296
    hist
~. ,: #/.~
    hist z
        1      3       2     4    5  7   6 8 9
40500537 405764 4048327 40574 4095 35 410 4 1
    NB. i.e. one run of 9 digits, 4 of length 8 etc.
    timex 'hist z'
0.295335 536872960
    exit 0

MBpro-3:JKTststs jkt$ jb
    JVERSION
Engine: j901/j64avx2/darwin
Release-c: commercial/2020-01-11T12:24:26
Library: 9.01.18
Platform: Darwin 64
Installer: J901 install
InstallPath: /applications/j901
Contact: www.jsoftware.com
    q=. (50e6 ?.@$ 10){'0123456789'
    timex 'z=. rl q'
6.56145 649995392
    hist z
        1      3       2     4    5  7   6 8 9
40500537 405764 4048327 40574 4095 35 410 4 1
    6.56145 % 1.720735
3.813167048
    exit 0
MBpro-3:JKTststs jkt$

What surprised me was that the run length function rl took more space and about 
4 times  as long in J9.01 as in J8.07 - most things I try are the other way 
around.

Have others had similar experiences?
Does anyone see a reason my run length verb should bog down?

- joey


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