Resistance network calculator: Difference between revisions
Added Perl example
(→{{header|Python}}: Changed `i+argmax` to built-in `max` with `key=func`) |
SqrtNegInf (talk | contribs) (Added Perl example) |
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</pre>
=={{header|Perl}}==
<lang perl>use strict;
use warnings;
sub gauss {
our @m; local *m = shift;
my ($lead, $rows, $cols) = (0, scalar(@m), scalar(@{$m[0]}));
foreach my $r (0 .. $rows - 1) {
$lead < $cols or return;
my $i = $r;
until ($m[$i][$lead])
{++$i == $rows or next;
$i = $r;
++$lead == $cols and return;}
@m[$i, $r] = @m[$r, $i];
my $lv = $m[$r][$lead];
$_ /= $lv foreach @{ $m[$r] };
my @mr = @{ $m[$r] };
foreach my $i (0 .. $rows - 1)
{$i == $r and next;
($lv, my $n) = ($m[$i][$lead], -1);
$_ -= $lv * $mr[++$n] foreach @{ $m[$i] };}
++$lead;}
}
sub network {
my($n,$k0,$k1,$grid) = @_;
my @m;
push @m, [(0)x($n+1)] for 1..$n;
for my $resistor (split '\|', $grid) {
my ($a,$b,$r_inv) = split /\s+/, $resistor;
my $r = 1 / $r_inv;
$m[$a][$a] += $r;
$m[$b][$b] += $r;
$m[$a][$b] -= $r if $a > 0;
$m[$b][$a] -= $r if $b > 0;
}
$m[$k0][$k0] = 1;
$m[$k1][ -1] = 1;
gauss(\@m);
return $m[$k1][-1];
}
for (
[ 7, 0, 1, '0 2 6|2 3 4|3 4 10|4 5 2|5 6 8|6 1 4|3 5 6|3 6 6|3 1 8|2 1 8' ],
[ 3*3, 0, 3*3-1, '0 1 1|1 2 1|3 4 1|4 5 1|6 7 1|7 8 1|0 3 1|3 6 1|1 4 1|4 7 1|2 5 1|5 8 1' ],
[ 4*4, 0, 4*4-1, '0 1 1|1 2 1|2 3 1|4 5 1|5 6 1|6 7 1|8 9 1|9 10 1|10 11 1|12 13 1|13 14 1|14 15 1|0 4 1|4 8 1|8 12 1|1 5 1|5 9 1|9 13
[ 4, 0, 3, '0 1 150|0 2 50|1 3 300|2 3 250' ],
) {
printf "%10.3f\n", network(@$_);
}
</lang>
{{out}}
<pre> 10.000
1.500
1.857
180.000</pre>
=={{header|Perl 6}}==
{{trans|Python}}
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