Math::LinearApprox - fast linear approximation of 2D sequential points
use Math::LinearApprox qw( linear_approx linear_approx_str );
# OO style
my @points = ( 0, 4 );
my $la = Math::LinearApprox->new();
my $la = Math::LinearApprox->new(\@points);
$la->add_point( 2, 1 );
$la->add_point( 7, 0 );
print $la->equation_str();
my ($A, $B) = $la->equation();
# Procedural style
my @points = ( 0, 4, 2, 1, 7, 0 );
print linear_approx_str(\@points);
Typically there are several methods of linear approximation in use to approximate 2D points series, including least squares method. All of them requires a lot of multiplication operations.
I have invented new numerical method which requires less complex instructions and much more suitable for approximation of really huge arrays of data. This method description and comparative analysis will be published in a separate scientific paper soon.
Currently there is a requirement for all the points to be sorted by X axis. Also currently this method uses all the points and does not include any filtering abilities. Hopefully, they will be added soon.
Each point should be specified by $x, $y
pair of coordinates.
You can either push the points from anywhere into the model -- they are not
being saved AS-IS -- or populate the model with @points = ($x, $y, ...)
reference.
To fill the model with data one can call $obj->add_point( $x, $y )
.
This function returns nothing meaningful.
Perl will cast anything illegal passed as $x, $y
into numbers.
So it is your responsibility to validate your points in advance.
$x
is X coordinate of the point.$y
is Y coordinate of the point.
Since any line that is not perpendicular to X axis could be represented
in a form of y = A * x + B
, then $obj->equation()
returns
($A, $B)
coefficients. The method returns undef unless the model could
not be represented in such a form.
The $obj->equation_str
returns stringified equation of the model either
in form "y = A * x + B"
, or "x = X"
in case all points are vertically
distributed. The method dies unless the model could not be approximated.
In most cases it is due to absense of points in the model.
The linear_approx( \@points )
is a procedural style alias for
new( \@points )->equation()
.
The linear_approx_str( \@points )
is a procedural style alias for
new( \@points )->equation_str()
.
$obj = Math::LinearApprox->new()
is an object constructor
that will instantiate the approximation model. The only parameter is
optional -- reference to array of points: [$x1, $y1, $x2, $y2, ...]
.
Sergei Zhmylev, <zhmylove@cpan.org>
Please report any bugs or feature requests to official GitHub page at
https://github.com/zhmylove/math-linearapprox.
You also can use official CPAN bugtracker by reporting to
bug-math-linearapprox at rt.cpan.org
, or through the web interface at
https://rt.cpan.org/NoAuth/ReportBug.html?Queue=Math-LinearApprox.
I will be notified, and then you'll automatically be notified of progress
on your bug as I make changes.
To install this module, run the following commands:
$ perl Makefile.PL
$ make
$ make test
$ make install
This software is Copyright (c) 2021 by Sergei Zhmylev.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)