NAME
Tie::Hash::Interpolate - tied mathematical interpolation/extrapolation
SYNOPSIS
use Tie::Hash::Interpolate;
## use tie interface
tie my %lut, 'Tie::Hash::Interpolate', extrapolate => 'linear';
$lut{3} = 4;
$lut{5} = 6;
print $lut{4}; ## prints 5
print $lut{6.5}; ## prints 7.5
## or constructor interface
my $lut = Tie::Hash::Interpolate->new( extrapolate => 'linear' );
$lut->{3} = 4;
$lut->{5} = 6;
print $lut->{4}; ## prints 5
print $lut->{6.5}; ## prints 7.5
DESCRIPTION
Tie::Hash::Interpolate
provides a mechanism for using a hash as a lookup table for interpolated and extrapolated values.
Hashes can either be tied using the tie
builtin or by constructing one with the new()
method.
After your hash is tied (NOTE: key-value pairs added prior to the tie will be ignored), insert your known key-value pairs. If you then fetch a key that does not exist, an interpolation or extrapolation will be performed as necessary. If you fetch a key that does exist, the value stored for that key will be returned.
OPTIONS
Options can be passed to tie
after the Tie::Hash::Interpolate
name is given, or directly to new()
as key-value pairs.
tie my %lut, 'Tie::Hash::Interpolate', extrapolate => 'fatal';
## or
my $lut = Tie::Hash::Interpolate->new( one_key => 'constant' );
extrapolate
This option controls the behavior of the tied hash when a key is requested outside the range of known keys. Valid extrapolate
values include:
linear
(default)extrapolate linearly based on the two nearest points
constant
keep the nearest value constant rather than extrapolating
fatal
throw a fatal exception
undef
return
undef
one_key
This option controls the behavior of the tied hash when a key is requested and only one key exists in the hash. Valid one_key
values include:
fatal
(default)throw a fatal exception
constant
all fetches return the one value that exists
undef
return
undef
TO DO
- - support multiple dimensions
- - support autovivification of tied hashes
- - set a per-instance mode for insertion or lookup
- - be smarter (proximity based direction) about searching when doing interpolation
AUTHOR
Daniel B. Boorstein, <danboo@cpan.org>
COPYRIGHT AND LICENSE
Copyright 2004 by Daniel B. Boorstein
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.