Linear Interpolation

#!/usr/bin/perl
#use warnings;
use Data::Dumper;
use FileHandle;
use FindBin;
#use strict;
use lib "$FindBin::Bin/../CLAPv3/";
use lib "$FindBin::Bin/../CLAPv3/Math/Interpolator/";
use Math::Interpolate;
#use PDL::Interpolate;
#use Math::Interpolate qw(derivatives constant_interpolate
#                          linear_interpolate robust_interpolate);
use Math::Interpolate qw(derivatives linear_interpolate);
#use Math::Interpolator;
#use Math::Interpolator::Linear;
#use Math::Interpolator::Source;
#use Math::Interpolator::Knot;
#### Done  in Hashes

our %data;
our %datac;
&intro;

sub intro {
	print " Welcome to C.L.A.P. 1.0\n\n";
	&calcscan;
	&calccsv;
}
sub calcscan {
	#@files = qw($redscan $bluescan $greenscan);
	$redscan = 'red_scan.txt';
	$bluescan = 'blue_scan.txt';
	$greenscan = 'green_scan.txt';
		open (FH, $redscan) or die "Oooooh Snap ";
		while (<FH>) {
			chomp;
			next if $. < 417;
			next if $. > 3664;
			 ($key,$value) = split (' ');
			$data{$key}= $value;
			#print dump(\%data);
			foreach $key (sort {$a <=> $b} keys %data) {
			}
		}
		close FH;
}
sub calccsv {
	$csv = 'CLAP_sensor_sensitivity.csv';
	open $FHc, $csv or die "Oh Snap";
	while (<$FHc>) {
		chomp;
		next if $. < 2;
		#next if $. > 100;
		 ($keyc,$valuec) = split (' ');
		chop($keyc);
		$data{$keyc}= $valuec;
		#print Dumper(\%data);
		foreach $keyc (sort {$a <=> $b} keys %datac) {}
		my @x = $keyc;
		my @y = $valuec;
		my @dy =  derivatives( \@x, \@y);
		my($l_y, $l_dy) = linear_interpolate($value, \@x, \@y);
		print $l_y, "\n";
		
}
close $FHc;



}

#!/usr/bin/perl -w
use strict;
use Time::Local;
use Data::Dumper;

my @data;
my @graph;
my $one_day = 60*60*24;    #one day in seconds

while (<DATA>)
{
   next if /^\s*$/;                #skip blank lines
   my ($date, $weight) = split;
   my $epoch = epoch($date);
   push (@data, [$epoch, $weight]);
}

# input data is sorted already sorted
# But the algortihm depends upon sorted date information
# so I did that to make sure
#
  @data = sort{$a->[0] <=> $b->[0]} @data; 
                                          
# axis x will be adjusted to #days from the date of first data
# axis y is in weight  

my ($x_base_epoch, $y1) = @{shift(@data)};
my $x1_day =0;
                                            
foreach my $r_xy(@data)
{
   my ($x2, $y2) = @$r_xy;
   $x2 -= $x_base_epoch;
   my $x2_day = int($x2/$one_day);
     
   # slope is delta weight/ delta days
     my $slope = ($y2-$y1)/($x2_day-$x1_day); 
   
   # fill in missing data points...
   # by linear interpolation 
   
   for (; $x1_day< $x2_day; $x1_day++) # x interval not tested for
                                       # other than 1
   {
      my $y = $slope*($x1_day-$x2_day) + $y2;
      push @graph, [$x1_day,$y];
   }   
         
   $y1= $y2;
}

#fix-up for last data point
my ($fx,$fy) = @{$data[-1]};
push @graph, [($fx-$x_base_epoch)/$one_day, $fy];

### data to graph is in @graph  ###
### I leave that part to the OP ###
print "$_->[0] $_->[1]\n" foreach @graph;

sub epoch
{
   my $date = shift;
   my ($month, $day, $year) = split(m|/|,$date);
   my $time = timelocal(0,0,0, $day, $month-1, $year-1900); 
   return $time;
}

C:\temp>cat ols.pl
use Statistics::LineFit;

my @x = ( 10, 20, 30 );
my @y = ( 10, 40, 70 );

$ols = Statistics::LineFit->new;
$ols->setData( \@x, \@y );

my ($b, $m) = $ols->coefficients;

my $x2 = 15;

printf "Interpolated f(%d) = %d\n", $x2, ($x2 * $m) + $b;

C:\temp>perl ols.pl
Interpolated f(15) = 25

($keyc,$valuec) = split (' ');
		chop($keyc);
		$datac{$keyc}= $valuec;
		foreach $keyc (sort {$a <=> $b} keys %datac) { print $keyc; }

for $key (sort keys %hash) {
  unless( defined $last_key ) {
    $last_key = $key;
    next;
  }
  # ... do something with $last_key and $hash{$last_key}
  # ... and $key and $hash{$key}
}

push @array, [ split /\s+/ ] while <FILE>;
@array= sort { $a->[0] <=> $b->[0] } @array;

for $i ( 1 .. $#array ) {
  # ... do something with $array[$i-1][0] and $array[$i-1][1]
  # ... and $array[$i][0] and $array[$i][1]
}

sub calccsv {
	$csv = 'CLAP_sensor_sensitivity.csv';
	open $FHc, $csv or die "Oh Snap";
	while (<$FHc>) {
		chomp;
		next if $. < 2;
		next if $. > 100;
		 ($keyc,$valuec) = split (' ');
		chop($keyc);
		$datac{$keyc}= $valuec;
		for $key (sort keys %datac) {
			unless ( defined $last_key) {
				$last_key = $keyc;
				next;
		} 
		@newkey = $last_key + $datac{$last_key};
		foreach (@newkey) {
			print $newkey[1..100], "\n";
}	
		
		#return ($keyc, $valuec);

}