compute-hamming
v1.1.0
Published
Computes the Hamming distance between two sequences.
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Hamming Distance
Computes the Hamming distance between two sequences.
In information theory, the Hamming distance is number of differences between two sequences of the same length. These sequences may be represented as character strings, binary strings, or arrays.
Installation
$ npm install compute-hamming
For use in the browser, use browserify.
Usage
var hamming = require( 'compute-hamming' );
hamming( a, b[, accessor] )
Computes the Hamming distance between two sequences. The sequences must be either both equal length strings
or equal length arrays
.
var a = 'this is a string.',
b = 'thiz iz a string.';
var dist = hamming( a, b );
// returns 2
var c = [ 5, 23, 2, 5, 9 ],
d = [ 3, 21, 2, 5, 14 ];
dist = hamming( c, d );
// returns 3
To compute the Hamming distance between nested array
values, provide an accessor function
for accessing array
values.
var a = [
{'x':2},
{'x':4},
{'x':5},
{'x':3},
{'x':8},
{'x':2}
];
var b = [
[1,3],
[2,1],
[3,5],
[4,3],
[5,7],
[6,2]
];
function getValue( d, i, j ) {
if ( j === 0 ) {
return d.x;
}
return d[ 1 ];
}
var dist = hamming( a, b, getValue );
// returns 3
The accessor function
is provided three arguments:
- d: current datum.
- i: current datum index.
- j: sequence index; e.g., sequence
a
has index0
and sequenceb
has index1
.
Examples
To run the example code from the top-level application directory,
$ node ./examples/index.js
Tests
Unit
Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:
$ make test
All new feature development should have corresponding unit tests to validate correct functionality.
Test Coverage
This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:
$ make test-cov
Istanbul creates a ./reports/coverage
directory. To access an HTML version of the report,
$ make view-cov
License
Copyright
Copyright © 2014-2015. Athan Reines.