Yes, I get similar timings in J602, J807 and J901 under Windows 10.
I happen to have found that rl performs better (for this example) on the
list of indices
than on the parent string, inadvertently, as I was looking for the
maximum of q!
In JQt 9.01:
Callinjg the long q "ql",
iql =: i.~ q
timex'rl iql'
2.40118
timex'rl ql'
7.50985
while this clunky work in progress gives:
timex'(+/\ inv @: I.@: ~: >:@(>./),~}.) iql'
1.24205
(It's almost right: !
10 {.+/\ inv ( I.@: ~: >:@(>./),~}.) iql
0 1 1 1 1 1 3 1 1 1
10 {.rl iql
1 1 1 1 1 1 3 1 1 1
)
Space isn't so good:
ts'(+/\ inv @: I.@: ~: >:@(>./),~}.) iql' NB. time and space
1.32368 1.67773e9
ts'rl iql'
2.42318 6.49995e8
So - why is the elegant rl "worse" for timing than my horrible cobble?
Mike
On 15/01/2020 08:18, bill lam wrote:
I have no idea, but I got similar results on linux
time space
j907 : 5.05662 6.49995e8
j807 : 1.24932 6.49991e8
j602 : 0.514155 6.03982e8
A bigger surprise is j602 being the fastest, almost 10 times
faster than j901.
Tue, 14 Jan 2020, Joey K Tuttle написал(а):
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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