NAME
Math::SZaru::QuantileEstimator - Quantile estimation based on Munro-Paterson algorithm
SYNOPSIS
use Math::SZaru::QuantileEstimator;
my $ue = Math::SZaru::QuantileEstimator->new($maxelems);
$ue->add_elem("foo");
# add many more elems using add_elem ...
my $inserted_elems_count = $ue->tot_elems;
my $estimated_unique_count = $ue->estimate();DESCRIPTION
Math::SZaru::QuantileEstimator provides a statistical estimate of quantiles in a large data set (or stream). It uses the algorithm published by Munro and Paterson: Munro & Paterson, "Selection and Sorting with Limited Storage", Theoretical Computer Science, Vol 12, p 315-323, 1980.
METHODS
new
Constructor. Expects an integer indicating the number of quantiles to calculate. In a nutshell, passing 101 will mean that the return value of the estimate call (see below) will return a list of min, 1st-percentile, 2nd-percentile, ..., 99th-percentile, max (min + 100 = 101). Other values cause the space between min and max to be differently divided. Asking for only two quantiles will just yield min/max to be tracked. Asking for three quantiles will add the median (50th percentile).
add_elem
Given a floating point number, adds the number to the QuantileEstimator.
add_elems
Same as add_elem, but accepts an arbitrary list of numbers to insert into the estimator at once.
tot_elems
Returns the total count of the number of elements that were added to the estimator.
estimate
Returns the estimated quantiles in a raference to an array as described in the new documentation above.
SEE ALSO
SZaru: "SZaru/" in llamerada.github.com
Sawzall: http://code.google.com/p/szl/
AUTHOR
Steffen Mueller, <smueller@cpan.org>
COPYRIGHT AND LICENSE
The Perl wrapper of the SZaru library is:
Copyright (C) 2013 by Steffen Mueller
Just like SZaru itself, it is licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.