Merge pull request #4 from compute-io/develop

[UPDATE] support new matrix api.

README.md

@@ -4,7 +4,7 @@ Mean
 
 > Computes the [arithmetic mean](http://en.wikipedia.org/wiki/Arithmetic_mean).
 
-The [arithmetic mean](http://en.wikipedia.org/wiki/Arithmetic_mean) is defined by
+The [arithmetic mean](http://en.wikipedia.org/wiki/Arithmetic_mean) is defined as
 
 <div class="equation" align="center" data-raw-text="\mu = \frac{1}{N} \sum_{i=0}^{N-1} x_i" data-equation="eq:arithmetic_mean">
 	<img src="https://cdn.rawgit.com/compute-io/mean/c98aa32b6fea5b040092dbf950cba79eb25e25b8/docs/img/eqn.svg" alt="Equation for the arithmetic mean.">
@@ -14,13 +14,13 @@ The [arithmetic mean](http://en.wikipedia.org/wiki/Arithmetic_mean) is defined b
 where `x_0, x_1,...,x_{N-1}` are individual data values and `N` is the total number of values in the data set.
 
 
-### Installation
+## Installation
 
 ``` bash
 $ npm install compute-mean
 ```
 
-### Usage
+## Usage
 
 ``` javascript
 var mean = require( 'compute-mean' );
@@ -164,7 +164,7 @@ mu = mean( matrix( [10,0] ) );
 
 
 
-### Examples
+## Examples
 
 ``` javascript
 var matrix = require( 'dstructs-matrix' ),

lib/matrix.js

@@ -14,6 +14,7 @@ function mean( out, mat, dim ) {
 		mu,
 		M, N,
 		s0, s1,
+		o,
 		i, j, k;
 
 	if ( dim === 1 ) {
@@ -32,8 +33,9 @@ function mean( out, mat, dim ) {
 	if ( M === 0 || N === 0 ) {
 		return null;
 	}
+	o = mat.offset;
 	for ( i = 0; i < M; i++ ) {
-		k = i * s0;
+		k = o + i*s0;
 		mu = 0;
 		for ( j = 0; j < N; j++ ) {
 			delta = mat.data[ k + j*s1 ] - mu;

package.json

@@ -44,16 +44,16 @@
   },
   "dependencies": {
     "compute-array-constructors": "^1.0.0",
-    "dstructs-matrix": "^1.0.0",
+    "dstructs-matrix": "^2.0.0",
     "validate.io-array-like": "^1.0.0",
     "validate.io-function": "^1.0.2",
-    "validate.io-matrix-like": "^1.0.0",
+    "validate.io-matrix-like": "^1.0.2",
     "validate.io-object": "^1.0.4",
     "validate.io-positive-integer": "^1.0.0",
     "validate.io-string-primitive": "^1.0.0"
   },
   "devDependencies": {
-    "chai": "2.x.x",
+    "chai": "3.x.x",
     "coveralls": "^2.11.1",
     "istanbul": "^0.3.0",
     "jshint": "^2.x.x",

test/test.matrix.js

@@ -1,4 +1,4 @@
-/* global describe, it, require */
+/* global describe, it, require, beforeEach */
 'use strict';
 
 // MODULES //
@@ -31,8 +31,10 @@ describe( 'matrix mean', function tests() {
 	for ( i = 0; i < data.length; i++ ) {
 		data[ i ] = i;
 	}
-	mat = matrix( data, [5,5], 'int8' );
 
+	beforeEach( function before() {
+		mat = matrix( data, [5,5], 'int8' );
+	});
 
 	it( 'should export a function', function test() {
 		expect( mean ).to.be.a( 'function' );
@@ -52,6 +54,15 @@ describe( 'matrix mean', function tests() {
 		expected = '2;7;12;17;22';
 
 		assert.strictEqual( mu.toString(), expected );
+
+		// Flip a matrix up-down:
+		mat.strides[ 0 ] *= -1;
+		mat.offset = mat.length + mat.strides[ 0 ];
+
+		mu = mean( out, mat );
+		expected = '22;17;12;7;2';
+
+		assert.strictEqual( mu.toString(), expected, 'flipud' );
 	});
 
 	it( 'should compute the arithmetic mean along matrix rows', function test() {
@@ -63,6 +74,15 @@ describe( 'matrix mean', function tests() {
 		expected = '10,11,12,13,14';
 
 		assert.strictEqual( mu.toString(), expected );
+
+		// Flip a matrix left-right:
+		mat.strides[ 1 ] *= -1;
+		mat.offset = mat.strides[ 0 ] - 1;
+
+		mu = mean( out, mat, 1 );
+		expected = '14,13,12,11,10';
+
+		assert.strictEqual( mu.toString(), expected, 'fliplr' );
 	});
 
 	it( 'should return null if provided a matrix having one or more zero dimensions', function test() {