Skip to content

Commit 7c108ad

Browse files
gururaj1512kgrytestdlib-bot
authored
feat: add stats/nanmean
PR-URL: #7968 Co-authored-by: Athan Reines <[email protected]> Reviewed-by: Athan Reines <[email protected]> Co-authored-by: stdlib-bot <[email protected]>
1 parent 0144b30 commit 7c108ad

File tree

13 files changed

+2820
-0
lines changed

13 files changed

+2820
-0
lines changed

‎lib/node_modules/@stdlib/stats/nanmean/README.md

Lines changed: 296 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,296 @@
1+
<!--
2+
3+
@license Apache-2.0
4+
5+
Copyright (c) 2025 The Stdlib Authors.
6+
7+
Licensed under the Apache License, Version 2.0 (the "License");
8+
you may not use this file except in compliance with the License.
9+
You may obtain a copy of the License at
10+
11+
http://www.apache.org/licenses/LICENSE-2.0
12+
13+
Unless required by applicable law or agreed to in writing, software
14+
distributed under the License is distributed on an "AS IS" BASIS,
15+
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16+
See the License for the specific language governing permissions and
17+
limitations under the License.
18+
19+
-->
20+
21+
# nanmean
22+
23+
> Compute the [arithmetic mean][arithmetic-mean] along one or more [ndarray][@stdlib/ndarray/ctor] dimensions, ignoring `NaN` values.
24+
25+
<section class="intro">
26+
27+
The [arithmetic mean][arithmetic-mean] is defined as
28+
29+
<!-- <equation class="equation" label="eq:arithmetic_mean" align="center" raw="\mu = \frac{1}{n} \sum_{i=0}^{n-1} x_i" alt="Equation for the arithmetic mean."> -->
30+
31+
```math
32+
\mu = \frac{1}{n} \sum_{i=0}^{n-1} x_i
33+
```
34+
35+
<!-- <div class="equation" align="center" data-raw-text="\mu = \frac{1}{n} \sum_{i=0}^{n-1} x_i" data-equation="eq:arithmetic_mean">
36+
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@42d8f64d805113ab899c79c7c39d6c6bac7fe25c/lib/node_modules/@stdlib/stats/strided/nanmean/docs/img/equation_arithmetic_mean.svg" alt="Equation for the arithmetic mean.">
37+
<br>
38+
</div> -->
39+
40+
<!-- </equation> -->
41+
42+
</section>
43+
44+
<!-- /.intro -->
45+
46+
<section class="usage">
47+
48+
## Usage
49+
50+
```javascript
51+
var nanmean = require( '@stdlib/stats/nanmean' );
52+
```
53+
54+
#### nanmean( x\[, options] )
55+
56+
Computes the [arithmetic mean][arithmetic-mean] along one or more [ndarray][@stdlib/ndarray/ctor] dimensions, ignoring `NaN` values.
57+
58+
```javascript
59+
var array = require( '@stdlib/ndarray/array' );
60+
61+
var x = array( [ 1.0, NaN, -2.0, 4.0 ] );
62+
63+
var y = nanmean( x );
64+
// returns <ndarray>
65+
66+
var v = y.get();
67+
// returns 1.0
68+
```
69+
70+
The function has the following parameters:
71+
72+
- **x**: input [ndarray][@stdlib/ndarray/ctor]. Must have a real-valued or "generic" [data type][@stdlib/ndarray/dtypes].
73+
- **options**: function options (_optional_).
74+
75+
The function accepts the following options:
76+
77+
- **dims**: list of dimensions over which to perform a reduction. If not provided, the function performs a reduction over all elements in a provided input [ndarray][@stdlib/ndarray/ctor].
78+
- **dtype**: output ndarray [data type][@stdlib/ndarray/dtypes]. Must be a real-valued floating-point or "generic" [data type][@stdlib/ndarray/dtypes].
79+
- **keepdims**: boolean indicating whether the reduced dimensions should be included in the returned [ndarray][@stdlib/ndarray/ctor] as singleton dimensions. Default: `false`.
80+
81+
By default, the function performs a reduction over all elements in a provided input [ndarray][@stdlib/ndarray/ctor]. To perform a reduction over specific dimensions, provide a `dims` option.
82+
83+
```javascript
84+
var ndarray2array = require( '@stdlib/ndarray/to-array' );
85+
var array = require( '@stdlib/ndarray/array' );
86+
87+
var x = array( [ 1.0, NaN, -2.0, 4.0 ], {
88+
'shape': [ 2, 2 ],
89+
'order': 'row-major'
90+
});
91+
var v = ndarray2array( x );
92+
// returns [ [ 1.0, NaN ], [ -2.0, 4.0 ] ]
93+
94+
var y = nanmean( x, {
95+
'dims': [ 0 ]
96+
});
97+
// returns <ndarray>
98+
99+
v = ndarray2array( y );
100+
// returns [ -0.5, 4.0 ]
101+
102+
y = nanmean( x, {
103+
'dims': [ 1 ]
104+
});
105+
// returns <ndarray>
106+
107+
v = ndarray2array( y );
108+
// returns [ 1.0, 1.0 ]
109+
110+
y = nanmean( x, {
111+
'dims': [ 0, 1 ]
112+
});
113+
// returns <ndarray>
114+
115+
v = y.get();
116+
// returns 1.0
117+
```
118+
119+
By default, the function excludes reduced dimensions from the output [ndarray][@stdlib/ndarray/ctor]. To include the reduced dimensions as singleton dimensions, set the `keepdims` option to `true`.
120+
121+
```javascript
122+
var ndarray2array = require( '@stdlib/ndarray/to-array' );
123+
var array = require( '@stdlib/ndarray/array' );
124+
125+
var x = array( [ 1.0, NaN, -2.0, 4.0 ], {
126+
'shape': [ 2, 2 ],
127+
'order': 'row-major'
128+
});
129+
130+
var v = ndarray2array( x );
131+
// returns [ [ 1.0, NaN ], [ -2.0, 4.0 ] ]
132+
133+
var y = nanmean( x, {
134+
'dims': [ 0 ],
135+
'keepdims': true
136+
});
137+
// returns <ndarray>
138+
139+
v = ndarray2array( y );
140+
// returns [ [ -0.5, 4.0 ] ]
141+
142+
y = nanmean( x, {
143+
'dims': [ 1 ],
144+
'keepdims': true
145+
});
146+
// returns <ndarray>
147+
148+
v = ndarray2array( y );
149+
// returns [ [ 1.0 ], [ 1.0 ] ]
150+
151+
y = nanmean( x, {
152+
'dims': [ 0, 1 ],
153+
'keepdims': true
154+
});
155+
// returns <ndarray>
156+
157+
v = ndarray2array( y );
158+
// returns [ [ 1.0 ] ]
159+
```
160+
161+
By default, the function returns an [ndarray][@stdlib/ndarray/ctor] having a [data type][@stdlib/ndarray/dtypes] determined by the function's output data type [policy][@stdlib/ndarray/output-dtype-policies]. To override the default behavior, set the `dtype` option.
162+
163+
```javascript
164+
var getDType = require( '@stdlib/ndarray/dtype' );
165+
var array = require( '@stdlib/ndarray/array' );
166+
167+
var x = array( [ 1.0, NaN, -2.0, 4.0 ], {
168+
'dtype': 'generic'
169+
});
170+
171+
var y = nanmean( x, {
172+
'dtype': 'float64'
173+
});
174+
// returns <ndarray>
175+
176+
var dt = getDType( y );
177+
// returns 'float64'
178+
```
179+
180+
#### nanmean.assign( x, out\[, options] )
181+
182+
Computes the [arithmetic mean][arithmetic-mean] along one or more [ndarray][@stdlib/ndarray/ctor] dimensions, ignoring `NaN` values, and assigns results to a provided output [ndarray][@stdlib/ndarray/ctor].
183+
184+
```javascript
185+
var array = require( '@stdlib/ndarray/array' );
186+
var zeros = require( '@stdlib/ndarray/zeros' );
187+
188+
var x = array( [ 1.0, NaN, -2.0, 4.0 ] );
189+
var y = zeros( [] );
190+
191+
var out = nanmean.assign( x, y );
192+
// returns <ndarray>
193+
194+
var v = out.get();
195+
// returns 1.0
196+
197+
var bool = ( out === y );
198+
// returns true
199+
```
200+
201+
The method has the following parameters:
202+
203+
- **x**: input [ndarray][@stdlib/ndarray/ctor]. Must have a real-valued or generic [data type][@stdlib/ndarray/dtypes].
204+
- **out**: output [ndarray][@stdlib/ndarray/ctor].
205+
- **options**: function options (_optional_).
206+
207+
The method accepts the following options:
208+
209+
- **dims**: list of dimensions over which to perform a reduction. If not provided, the function performs a reduction over all elements in a provided input [ndarray][@stdlib/ndarray/ctor].
210+
211+
</section>
212+
213+
<!-- /.usage -->
214+
215+
<section class="notes">
216+
217+
## Notes
218+
219+
- Setting the `keepdims` option to `true` can be useful when wanting to ensure that the output [ndarray][@stdlib/ndarray/ctor] is [broadcast-compatible][@stdlib/ndarray/base/broadcast-shapes] with ndarrays having the same shape as the input [ndarray][@stdlib/ndarray/ctor].
220+
- The output data type [policy][@stdlib/ndarray/output-dtype-policies] only applies to the main function and specifies that, by default, the function must return an [ndarray][@stdlib/ndarray/ctor] having a real-valued floating-point or "generic" [data type][@stdlib/ndarray/dtypes]. For the `assign` method, the output [ndarray][@stdlib/ndarray/ctor] is allowed to have any supported output [data type][@stdlib/ndarray/dtypes].
221+
222+
</section>
223+
224+
<!-- /.notes -->
225+
226+
<section class="examples">
227+
228+
## Examples
229+
230+
<!-- eslint no-undef: "error" -->
231+
232+
```javascript
233+
var uniform = require( '@stdlib/random/base/uniform' );
234+
var filledarrayBy = require( '@stdlib/array/filled-by' );
235+
var bernoulli = require( '@stdlib/random/base/bernoulli' );
236+
var getDType = require( '@stdlib/ndarray/dtype' );
237+
var ndarray2array = require( '@stdlib/ndarray/to-array' );
238+
var ndarray = require( '@stdlib/ndarray/ctor' );
239+
var nanmean = require( '@stdlib/stats/nanmean' );
240+
241+
function rand() {
242+
if ( bernoulli( 0.8 ) < 1 ) {
243+
return NaN;
244+
}
245+
return uniform( 0.0, 20.0 );
246+
}
247+
248+
// Generate an array of random numbers:
249+
var xbuf = filledarrayBy( 25, 'generic', rand );
250+
251+
// Wrap in an ndarray:
252+
var x = new ndarray( 'generic', xbuf, [ 5, 5 ], [ 5, 1 ], 0, 'row-major' );
253+
console.log( ndarray2array( x ) );
254+
255+
// Perform a reduction:
256+
var y = nanmean( x, {
257+
'dims': [ 0 ]
258+
});
259+
260+
// Resolve the output array data type:
261+
var dt = getDType( y );
262+
console.log( dt );
263+
264+
// Print the results:
265+
console.log( ndarray2array( y ) );
266+
```
267+
268+
</section>
269+
270+
<!-- /.examples -->
271+
272+
<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
273+
274+
<section class="related">
275+
276+
</section>
277+
278+
<!-- /.related -->
279+
280+
<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
281+
282+
<section class="links">
283+
284+
[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/ctor
285+
286+
[@stdlib/ndarray/dtypes]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/dtypes
287+
288+
[@stdlib/ndarray/output-dtype-policies]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/output-dtype-policies
289+
290+
[@stdlib/ndarray/base/broadcast-shapes]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/base/broadcast-shapes
291+
292+
[arithmetic-mean]: https://en.wikipedia.org/wiki/Arithmetic_mean
293+
294+
</section>
295+
296+
<!-- /.links -->

0 commit comments

Comments
 (0)