Script: ritz.pl

scripts/ritz.pl

+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use utf8;
+
+my ($file, $n) = @ARGV;
+defined($file) or die "USAGE: $0 filename [set number]\n";
+defined($n) or $n = -1;
+
+my @data = loadData($file, $n);
+
+printData(\@data);
+
+sub printData
+{
+	my ($a) = @_;
+	my $n = scalar(@$a);
+	for (my $i = 0; $i < $n; ++$i) {
+		print "$i ".$a->[$i]."\n";
+	}
+}
+
+sub loadData
+{
+	my ($file, $n) = @_;
+	open(FILE, "<", "$file") or die "$0: Cannot open $file : $!\n";
+	my @temp;
+
+	my $counter = 0;
+	while (<FILE>) {
+		next unless (/RitzEigenvalues: index\=\d+\|/);
+		s/RitzEigenvalues: index=\d+\|//;
+		chomp;
+		@temp = split;
+		last if ($counter++ == $n);
+	}
+
+	close(FILE);
+	my $m = scalar(@temp);
+	die "$0: No /RitzEigenvalues found in $file\n" if ($m == 0);
+	return @temp;
+}
+
+