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Re: anything faster than say [+] lines?

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From:
William Michels via perl6-users
Date:
September 26, 2019 18:24
Subject:
Re: anything faster than say [+] lines?
Message ID:
CAA99HCxBuJQ_3f+bhxKrU_EFgNXF8aggZ02G6Sjp0y8j2D0Aog@mail.gmail.com
Thank you, Andy and Joseph!


On Thu, Sep 26, 2019 at 8:47 AM Andy Bach <Andy_Bach@wiwb.uscourts.gov> wrote:
>
> >  Still, it's just "works for me":
>
> seq 1000000 | time perl6 -ne 'my $y += $_; END { print $y; }'
>
> I think that's still the wrong one - your missing the "Int"
> $ seq 1000000 | perl6 -ne 'my Int $y += $_; END { print $y; }'
> 500000500000
>
> though that works here, admittedly, my p6 is sort old
> This is Rakudo version 2018.03 built on MoarVM version 2018.03
> implementing Perl 6.c.
>
> I'm a little puzzled, I'd've thought the loop around the 'my Int $y' would redeclare a local $y each time.  Instead it behaves like:
> $ time perl6 -e 'my Int $y = 0;for ( 1 .. 1000000) { $y += $_} ;  say $y; '
>
> (which is signficantly faster ;-)
> 500000500000
> real 0m1.229s
> user 0m1.254s
> sys 0m0.040s
>
> )
> ________________________________
> From: Joseph Brenner <doomvox@gmail.com>
> Sent: Wednesday, September 25, 2019 11:13 PM
> To: William Michels <wjm1@caa.columbia.edu>
> Cc: Marc Chantreux <eiro@phear.org>; Vittore Scolari <vittore.scolari@gmail.com>; Elizabeth Mattijsen <liz@dijkmat.nl>; perl6 <perl6-users@perl.org>
> Subject: Re: anything faster than say [+] lines?
>
> Oh, wait.  I tried the wrong one-liner.  Still, it's just "works for me":
>
> seq 1000000 | time perl6 -ne 'my $y += $_; END { print $y; }'
> 50000050000029.29user 0.06system 0:28.41elapsed 103%CPU
> (0avgtext+0avgdata 76196maxresident)k
> 63328inputs+0outputs (32major+15588minor)pagefaults 0swaps
>
>
>
> On 9/25/19, Joseph Brenner <doomvox@gmail.com> wrote:
> > I just gave that one-liner a try, but I didn't see that error:
> >
> >> seq 1000000 | time perl6 -e 'say [+] lines'
> > 500000500000
> > 28.70user 0.07system 0:28.29elapsed 101%CPU (0avgtext+0avgdata
> > 74188maxresident)k
> > 63424inputs+0outputs (32major+15409minor)pagefaults 0swaps
> >
> >
> > perl6 --version
> > This is Rakudo Star version 2019.03.1 built on MoarVM version 2019.03
> > implementing Perl 6.d.
> >
> > uname -a
> > Linux fandango 4.9.0-8-686 #1 SMP Debian 4.9.144-3 (2019-02-02) i686
> > GNU/Linux
> >
> >
> >
> > On 9/24/19, William Michels via perl6-users <perl6-users@perl.org> wrote:
> >> I'm seeing a strange error. I started trying out Marc's original code,
> >> then tried to adapt some Perl5-type solutions from SO to see how they
> >> performed when re-written as Perl6. One thing I wanted to explicitly
> >> test was how restricting to an "Int" type affected performance.
> >>
> >> However, I found a surprising result: a sequence of one-million Ints
> >> throws an error, but a sequence of 999,999 Ints does not:
> >>
> >>> mbook:~ homedir$ seq 1000000 | time perl6 -e 'say [+] lines'
> >>> 500000500000
> >>>         4.81 real         4.86 user         0.20 sys
> >>> mbook:~ homedir$ seq 1000000 | time perl6 -ne 'my $y += $_; END { print
> >>> $y; }'
> >>> 500000500000        4.88 real         5.06 user         0.19 sys
> >>> mbook:~ homedir$ seq 1000000 | time perl6 -ne 'my Int $y += $_; END {
> >>> print $y; }'
> >>> Type check failed in assignment to $y; expected Int but got Num
> >>> (500000500000e0)
> >>>   in block <unit> at -e line 1
> >>> 499999500000        4.77 real         4.97 user         0.19 sys
> >>> mbook:~ homedir$ seq 999999 | time perl6 -ne 'my Int $y += $_; END {
> >>> print
> >>> $y; }'
> >>> 499999500000        4.86 real         5.05 user         0.19 sys
> >>> mbook:~ homedir$ perl6 -v
> >>> This is Rakudo version 2019.07.1 built on MoarVM version 2019.07.1
> >>> implementing Perl 6.d.
> >>> mbook:~ homedir$
> >>
> >> Any comments or explanation appreciated,
> >>
> >> Best Regards, Bill.
> >>
> >>
> >>
> >>
> >> On Tue, Sep 24, 2019 at 1:59 AM Marc Chantreux <eiro@phear.org> wrote:
> >>>
> >>> hello,
> >>>
> >>> > > > > nice ... but when x is ~ 75440 (not always), there is a problem
> >>> > > > What is x here?
> >>> > > sorry. x is the arg of seq (number of lines).
> >>> > That never happens on my laptop
> >>>
> >>> well.. so it's a problem with my station. nevermind :)
> >>>
> >>> thanks again for helping
> >>> marc
> >>
> >

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