Computes an element-wise division.
npm install compute-divideDivide
===
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> Computes an element-wise division.
`` bash`
$ npm install compute-divide
For use in the browser, use browserify.
` javascript`
var divide = require( 'compute-divide' );
#### divide( arr, x[, opts] )
Computes an element-wise division. x may be either an array of equal length or a numeric value.
` javascript
var arr = [ 2, 1, 4, 2 ],
out;
out = divide( arr, 2 );
// returns [ 1, 0.5, 2, 1 ]
out = divide( arr, [ 1, 2, 8, 8 ] );
// returns [ 2, 1, 0.5, 0.25 ]
`
The function accepts the following options:
* __copy__: boolean indicating whether to return a new array. Default: true.function
* __accessor__: accessor for accessing values in object arrays.
To mutate the input array (e.g., when input values can be discarded or when optimizing memory usage), set the copy option to false.
` javascript
var arr = [ 5, 3, 8, 3, 2 ];
var out = divide( arr, 4, {
'copy': false
});
// returns [ 1.25, 0.75, 0.5, 0.75, 0.5 ]
console.log( arr === out );
// returns true
`
__Note__: mutation is the array equivalent of a __slash-equal__ (/=).
For object arrays, provide an accessor function for accessing array values.
` javascript
var data = [
['beep', 5],
['boop', 3],
['bip', 8],
['bap', 3],
['baz', 2]
];
function getValue( d, i ) {
return d[ 1 ];
}
var out = divide( data, 4, {
'accessor': getValue
});
// returns [ 1.25, 0.75, 2, 0.75, 0.5 ]
`
When dividing values between two object arrays, provide an accessor function which accepts 3 arguments.
` javascript
var data = [
['beep', 5],
['boop', 3],
['bip', 8],
['bap', 3],
['baz', 2]
];
var arr = [
{'x': 4},
{'x': 5},
{'x': 6},
{'x': 5},
{'x': 3}
];
function getValue( d, i, j ) {
if ( j === 0 ) {
return d[ 1 ];
}
return d.x;
}
var out = divide( data, arr, {
'accessor': getValue
});
// returns [ 1.25, 0.6, ~1.33, 0.6, ~0.67 ]
`
__Note__: j corresponds to the input array index, where j=0 is the index for the first input array and j=1 is the index for the second input array.
` javascript
var divide = require( 'compute-divide' );
var data = new Array( 100 );
for ( var i = 0; i < data.length; i++ ) {
data[ i ] = Math.round( Math.random()*100 );
}
var out = divide( data, 10 );
console.log( out.join( '\n' ) );
`
To run the example code from the top-level application directory,
` bash`
$ node ./examples/index.js
Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:
` bash`
$ make test
All new feature development should have corresponding unit tests to validate correct functionality.
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:
` bash`
$ make test-cov
Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,
` bash``
$ make view-cov
---
Copyright © 2015. The Compute.io Authors.
[npm-image]: http://img.shields.io/npm/v/compute-divide.svg
[npm-url]: https://npmjs.org/package/compute-divide
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[travis-url]: https://travis-ci.org/compute-io/divide
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[dependencies-url]: https://david-dm.org/compute-io/divide
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[dev-dependencies-url]: https://david-dm.org/dev/compute-io/divide
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[github-issues-url]: https://github.com/compute-io/divide/issues