RosettaCodeData/Task/Numerical-integration/Perl-6/numerical-integration-1.pl6
2016-12-05 22:15:40 +01:00

54 lines
1.4 KiB
Raku

use MONKEY-SEE-NO-EVAL;
sub leftrect(&f, $a, $b, $n) {
my $h = ($b - $a) / $n;
$h * [+] do f($_) for $a, $a+$h ... $b-$h;
}
sub rightrect(&f, $a, $b, $n) {
my $h = ($b - $a) / $n;
$h * [+] do f($_) for $a+$h, $a+$h+$h ... $b;
}
sub midrect(&f, $a, $b, $n) {
my $h = ($b - $a) / $n;
$h * [+] do f($_) for $a+$h/2, $a+$h+$h/2 ... $b-$h/2;
}
sub trapez(&f, $a, $b, $n) {
my $h = ($b - $a) / $n;
my $partial-sum += f($_) * 2 for $a+$h, $a+$h+$h ... $b-$h;
$h / 2 * [+] f($a), f($b), $partial-sum;
}
sub simpsons(&f, $a, $b, $n) {
my $h = ($b - $a) / $n;
my $h2 = $h/2;
my $sum1 = f($a + $h2);
my $sum2 = 0;
for $a+$h, *+$h ... $b-$h {
$sum1 += f($_ + $h2);
$sum2 += f($_);
}
($h / 6) * (f($a) + f($b) + 4*$sum1 + 2*$sum2);
}
sub tryem($f, $a, $b, $n, $exact) {
say "\n$f\n in [$a..$b] / $n";
EVAL "my &f = $f;
say ' exact result: ', $exact;
say ' rectangle method left: ', leftrect &f, $a, $b, $n;
say ' rectangle method right: ', rightrect &f, $a, $b, $n;
say ' rectangle method mid: ', midrect &f, $a, $b, $n;
say 'composite trapezoidal rule: ', trapez &f, $a, $b, $n;
say ' quadratic simpsons rule: ', simpsons &f, $a, $b, $n;"
}
tryem '{ $_ ** 3 }', 0, 1, 100, 0.25;
tryem '1 / *', 1, 100, 1000, log(100);
tryem '*.self', 0, 5_000, 5_000_000, 12_500_000;
tryem '*.self', 0, 6_000, 6_000_000, 18_000_000;