Re^2: How to transpose lines faster?

[rsFalse]

On my PC, 2e3 x 2e3 matrices:

$transposed[ $i ++ ] .= chop while $_ (incorrect): 0.6s

$transposed[ $i ++ ] .= chop while length (correct) (by pryrt): 0.75s

$transposed[ $i ++ ] .= chop while /./ (assuming that dot match any input char): 1.35s

$transposed[ $i ++ ] .= chop while !/^$/: 1.35s

next are without reverse:

$transposed[ $i ++ ] .= $& while /./g: 1.85s

$transposed[ $i ++ ] .= substr $_, 0, 1, '' while length: 1.0s

$transposed[ $i ++ ] .= $_ for split //: 1.0s

push @out, join '', map substr( $_,$i,1 ), @in (by BrowserUK): 1.1s

(pryrt's substr+substr variant ommited)

[pryrt]

I'm actually curious how my multi-substr variant would perform in your bench... because in my tests (on two different machines), and much to my surprise, mine significantly outperforms the join-map-substr.

anomalous_map: 20 wallclock secs (17.09 usr +  0.16 sys = 17.25 CPU) @
+  2.03/s (n=35)
anomalous_two: 17 wallclock secs (15.12 usr +  0.08 sys = 15.20 CPU) @
+  2.04/s (n=31)
buk_substr: 16 wallclock secs (15.59 usr +  0.01 sys = 15.61 CPU) @  0
+.70/s (n=11)
with_chop_fixed: 16 wallclock secs (15.09 usr +  0.17 sys = 15.27 CPU)
+ @  2.23/s (n=34)
with_split: 16 wallclock secs (15.19 usr +  0.00 sys = 15.19 CPU) @  0
+.86/s (n=13)
with_substr: 15 wallclock secs (15.39 usr +  0.00 sys = 15.39 CPU) @  
+1.75/s (n=27)

                   Rate buk_substr with_split with_substr anomalous_ma
+p anomalous_two with_chop_fixed
buk_substr      0.705/s         --       -18%        -60%          -65
+%          -65%            -68%
with_split      0.856/s        21%         --        -51%          -58
+%          -58%            -62%
with_substr      1.75/s       149%       105%          --          -14
+%          -14%            -21%
anomalous_map    2.03/s       188%       137%         16%            -
+-           -0%             -9%
anomalous_two    2.04/s       189%       138%         16%            0
+%            --             -8%
with_chop_fixed  2.23/s       216%       160%         27%           10
+%            9%              --

anomalous_map: 16 wallclock secs (15.34 usr +  0.06 sys = 15.41 CPU) @
+  1.49/s (n=23)
anomalous_two: 15 wallclock secs (14.98 usr +  0.02 sys = 15.00 CPU) @
+  1.60/s (n=24)
buk_substr: 17 wallclock secs (16.56 usr +  0.03 sys = 16.59 CPU) @  0
+.30/s (n=5)
with_chop_fixed: 15 wallclock secs (15.22 usr +  0.02 sys = 15.23 CPU)
+ @  1.51/s (n=23)
with_split: 17 wallclock secs (17.41 usr +  0.00 sys = 17.41 CPU) @  0
+.34/s (n=6)
with_substr: 15 wallclock secs (15.50 usr +  0.00 sys = 15.50 CPU) @  
+1.29/s (n=20)

                   Rate buk_substr with_split with_substr anomalous_ma
+p with_chop_fixed anomalous_two
buk_substr      0.301/s         --       -13%        -77%          -80
+%            -80%          -81%
with_split      0.345/s        14%         --        -73%          -77
+%            -77%          -78%
with_substr      1.29/s       328%       274%          --          -14
+%            -15%          -19%
anomalous_map    1.49/s       395%       333%         16%            -
+-             -1%           -7%
with_chop_fixed  1.51/s       401%       338%         17%            1
+%              --           -6%
anomalous_two    1.60/s       431%       364%         24%            7
+%              6%            --

And yes, the anomalous_map, anomalous_two and with_chop_fixed seemed to go back and forth a lot, even on the first system. It's not had a lot of runs, so the timing's not very accurate. Trying with 200x200 on the second machine, to give it more runs per function:

                  Rate buk_substr with_split with_substr with_chop_fix
+ed anomalous_map anomalous_two
buk_substr      29.1/s         --       -15%        -77%            -7
+8%          -78%          -80%
with_split      34.3/s        18%         --        -73%            -7
+4%          -74%          -76%
with_substr      127/s       337%       271%          --             -
+2%           -5%          -12%
with_chop_fixed  130/s       348%       280%          3%              
+--           -3%          -10%
anomalous_map    134/s       360%       291%          5%              
+3%            --           -8%
anomalous_two    145/s       399%       323%         14%             1
+1%            8%            --

<Reveal this spoiler or all in this thread>