Moving Sum
Computes a moving sum over an array.
Installation
$ npm install compute-msum
For use in the browser, use browserify.
Usage
var msum = ;
msum( arr, window[, options] )
Slides a window
over an array
to compute a moving sum. For numeric arrays
,
var arr = 1 2 3 4 5 ;var values = ;// returns [ 3, 5, 7, 9 ]
The function accepts two options
:
- copy:
boolean
indicating whether to return a newarray
containing the computed sums. Default:true
. - accessor: accessor
function
for accessing values in objectarrays
.
To mutate the input array
(e.g., when input values can be discarded or when optimizing memory usage), set the copy
option to false
.
var arr = 1 2 3 4 5 ;var values =;// returns [ 3, 5, 7, 9 ]console;// returns true
For non-numeric arrays
, provide an accessor function
for accessing numeric array
values.
var arr ='x':1'x':2'x':3'x':4;{return dx;}var values =;// returns [ 3, 5, 7 ]
Note: the returned array
has length L - W + 1
, where L
is the length of the input array
and W
is the window
size.
Examples
var msum = ;var data = 50 ;for var i = 0; i < datalength; i++data i = Math * 100;var values = ;console;
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. Rebekah Smith.