Specifically Iterating through a file in perl - perl

Question

So, I have this script :
#!/usr/bin/perl
use strict;
use warnings;
use diagnostics;
use Math::Vector::Real;
use constant DEG_PER_RAD => 45 / atan2(1, 1);
my ( $source, $out ) = qw/ OUT4 OUTABA12 /;
open my $in_fh, '<', $source or die qq{Unable to open "$source" for input: $!\n};
open my $out_fh, '>', $out or die qq{Unable to open "$out" for output: $!\n};
my #data;
push #data, V(split) while <$in_fh>;
my #aoa;
for my $i ( 0 .. $#data ) {
for my $j ( 0 .. $#data ) {
my $val1 = $data[$i];
my $val2 = $data[$j];
if ($val1 != $val2) {
my $math = sqrt(($val1->[0] - $val2->[0])**2 +
($val1->[1] - $val2->[1])**2 +
($val1->[2] - $val2->[2])**2);
if ($math < 2.2) {
print "#$val1 #$val2 $math\n";
push #aoa, [#$val1, #$val2, $math];
}
}
}
}
for my $k ( 0 .. $#aoa-1 ) {
my $aoadata1 = $aoa[$k];
my $aoadata2 = $aoa[$k+1];
my $vect1 = [ #{ $aoa[$k] }[0..2] ];
my $vect2 = [ #{ $aoa[$k+1] }[0..2] ];
my $vect3 = [ #{ $aoa[$k] }[3..5] ];
my $vect4 = [ #{ $aoa[$k+1] }[3..5] ];
my $math1 = [ #{ $aoa[$k] }[6] ];
my $math2 = [ #{ $aoa[$k+1] }[6] ];
my #matha = #$math1;
my #mathb = #$math2;
my #vecta = #$vect1;
my #vectb = #$vect2;
my #vectc = #$vect3;
my #vectd = #$vect4;
if ( #vecta != #vectb ) {
print "1\n";
}
}
Which runs on a test file like so:
18.474525 20.161419 20.33903
21.999333 20.220667 19.786734
18.333228 21.649157 21.125111
20.371077 19.675844 19.77649
17.04323 19.3106 20.148842
22.941106 19.105412 19.069893
and it calculates the distance between each point and every other point, and if it's below a threshold push it to an array for later. (For testing purposes, I also have it printing it. )
What I've been stuck on is the bottom half - I'm trying to eventually get to the point where the bottom half of the script script will iterate between rows like so:
If the first triple set of values on row 1 is not identical to the first set of triple values on row two, print 180, but only if this is the only instance of this line. If there is ever a point where row one's values were equal to row two's, do not print 180 whatsoever.
I cannot, for the life of me, get it to work. Any help is appreciated.

Answer 1

I think this is correct
I've used the facilities of the Math::Vector::Real module as I described in a comment
I leave the vectors as objects and avoid accessing their their contents directly
I calculate the distance between $vec1 and $vec2 as abs($vec1 - $vec2
I use the class's stringify ability to display it instead of extracting the individual values in my code
I have also changed the intermediate data format. The distance is no longer kept because it's not necessary, and the array #groups now contains an array for each group of vector pairs that have a common first vector. Each group is of the form
[ $vec1, $vec2, $vec2, $vec2, ... ]
and I use the first function from List::Util to find the group that each new vector pair belongs in. If an existing group is found with a matching first value then the second vector is just pushed onto the end of the group; otherwise a new group is created that looks like [ $vec1, $vec2 ]
Once the #groups array is built, it is processed again to generate the output
If there are only two values in the group then they are $vec1 and $vec2 of a unique point. $vec1 is printed with 180
If there are more than two elements then a line of output is generated for every pair of $vec2 values, each containing the value $vec1 together with the angle between the two $vec2 vectors in the pair
use strict;
use warnings;
use Math::Vector::Real qw/ V /;
use List::Util qw / first /;
use constant DEG_PER_RAD => 45 / atan2(1, 1);
my ( $source, $out ) = qw/ OUT4 OUTABA12 /;
open my $in_fh, '<', $source or die qq{Unable to open "$source" for input: $!\n};
my #data = map V(split), <$in_fh>;
my #groups;
for my $vec1 ( #data ) {
for my $vec2 ( #data ) {
next if abs($vec1 - $vec2) > 2.2 or $vec1 == $vec2;
my $group = first { $_->[0] == $vec1 } #groups;
if ( $group ) {
push #$group, $vec2;
}
else {
push #groups, [ $vec1, $vec2 ];
}
}
}
open my $out_fh, '>', $out or die qq{Unable to open "$out" for output: $!\n};
select $out_fh;
for my $group ( #groups ) {
my ($vec1, #vec2) = #$group;
if ( #vec2 == 1 ) {
print "$vec1 180\n";
next;
}
for my $i ( 0 .. $#vec2-1 ) {
for my $j ( $i+1 .. $#vec2 ) {
my ($vec2a, $vec2b) = #vec2[$i, $j];
my $angle = atan2( $vec2a, $vec2b ) * DEG_PER_RAD;
print "$vec1 $angle\n";
}
}
}
output
{18.474525, 20.161419, 20.33903} 4.96831567625921
{18.474525, 20.161419, 20.33903} 1.65052300046634
{18.474525, 20.161419, 20.33903} 4.80888617553369
{21.999333, 20.220667, 19.786734} 4.22499387836286
{18.333228, 21.649157, 21.125111} 180
{20.371077, 19.675844, 19.77649} 5.09280172684743
{17.04323, 19.3106, 20.148842} 180
{22.941106, 19.105412, 19.069893} 180