text: /**
  * @license Apache-2.0
  *
  * Copyright (c) 2020 The Stdlib Authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *    http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
  
  'use strict';
  
  // MODULES //
  
  var resolve = require( 'path' ).resolve;
  var tape = require( 'tape' );
  var floor = require( '@stdlib/math-base-special-floor' );
  var isnanf = require( '@stdlib/math-base-assert-is-nanf' );
  var float64ToFloat32 = require( '@stdlib/number-float64-base-to-float32' );
  var Float32Array = require( '@stdlib/array-float32' );
  var tryRequire = require( '@stdlib/utils-try-require' );
  
  
  // VARIABLES //
  
  var snanvariancech = tryRequire( resolve( __dirname, './../lib/snanvariancech.native.js' ) );
  var opts = {
  	'skip': ( snanvariancech instanceof Error )
  };
  
  
  // TESTS //
  
  tape( 'main export is a function', opts, function test( t ) {
  	t.ok( true, __filename );
  	t.strictEqual( typeof snanvariancech, 'function', 'main export is a function' );
  	t.end();
  });
  
  tape( 'the function has an arity of 4', opts, function test( t ) {
  	t.strictEqual( snanvariancech.length, 4, 'has expected arity' );
  	t.end();
  });
  
  tape( 'the function calculates the population variance of a strided array (ignoring `NaN` values)', opts, function test( t ) {
  	var x;
  	var v;
  	var i;
  
  	x = new Float32Array( [ 1.0, -2.0, -4.0, 5.0, NaN, 0.0, 3.0 ] );
  
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( v, float64ToFloat32( 53.5/(x.length-1) ), 'returns expected value' );
  
  	x = new Float32Array( [ 1.0, NaN, NaN, -2.0, NaN, -4.0, NaN, 5.0, NaN, 0.0, 3.0, NaN ] ); // eslint-disable-line max-len
  
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( v, float64ToFloat32( 53.5/(x.length-6) ), 'returns expected value' );
  
  	x = new Float32Array( [ -4.0, NaN ] );
  
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( v, 0.0, 'returns expected value' );
  
  	x = new Float32Array( [ NaN, NaN ] );
  
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( [ NaN ] );
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( [ 4.0 ] );
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( v, 0.0, 'returns expected value' );
  
  	x = new Float32Array( 1e3 );
  	for ( i = 0; i < 1e3; i++ ) {
  		x[ i ] = 100.0;
  	}
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( v, 0.0, 'returns expected value' );
  
  	x = new Float32Array( [ NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN ] ); // eslint-disable-line max-len
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( 1e3 );
  	for ( i = 0; i < 1e3; i++ ) {
  		x[ i ] = NaN;
  	}
  	v = snanvariancech( x.length, 0, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'the function calculates the sample variance of a strided array (ignoring `NaN` values)', opts, function test( t ) {
  	var x;
  	var v;
  	var i;
  
  	x = new Float32Array( [ 1.0, -2.0, -4.0, 5.0, NaN, 0.0, 3.0 ] );
  
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( v, float64ToFloat32( 53.5/(x.length-2) ), 'returns expected value' );
  
  	x = new Float32Array( [ 1.0, NaN, NaN, -2.0, NaN, -4.0, NaN, 5.0, NaN, 0.0, 3.0, NaN ] ); // eslint-disable-line max-len
  
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( v, float64ToFloat32( 53.5/(x.length-7) ), 'returns expected value' );
  
  	x = new Float32Array( [ -4.0, NaN ] );
  
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( [ NaN, NaN ] );
  
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( [ NaN ] );
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( [ 4.0 ] );
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( 1e3 );
  	for ( i = 0; i < 1e3; i++ ) {
  		x[ i ] = 100.0;
  	}
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( v, 0.0, 'returns expected value' );
  
  	x = new Float32Array( [ NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN, NaN ] ); // eslint-disable-line max-len
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( 1e3 );
  	for ( i = 0; i < 1e3; i++ ) {
  		x[ i ] = NaN;
  	}
  	v = snanvariancech( x.length, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'if provided an `N` parameter less than or equal to `0`, the function returns `NaN`', opts, function test( t ) {
  	var x;
  	var v;
  
  	x = new Float32Array( [ 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( 0, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	v = snanvariancech( -1, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'if provided an `N` parameter equal to `1`, the function returns a population variance of `0` provided the first element is not `NaN`', opts, function test( t ) {
  	var x;
  	var v;
  
  	x = new Float32Array( [ 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( 1, 0, x, 1 );
  	t.strictEqual( v, 0.0, 'returns expected value' );
  
  	x = new Float32Array( [ NaN, 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( 1, 0, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'if provided an `N` parameter equal to `1`, the function returns a sample variance equal to `NaN`', opts, function test( t ) {
  	var x;
  	var v;
  
  	x = new Float32Array( [ 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( 1, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( [ NaN, 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( 1, 1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'if provided a `correction` parameter yielding a correction term less than or equal to `0`, the function returns `NaN`', opts, function test( t ) {
  	var x;
  	var v;
  
  	x = new Float32Array( [ 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( x.length, x.length, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	v = snanvariancech( x.length, x.length+1, x, 1 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'the function supports a `stride` parameter', opts, function test( t ) {
  	var N;
  	var x;
  	var v;
  
  	x = new Float32Array([
  		1.0,  // 0
  		2.0,
  		2.0,  // 1
  		-7.0,
  		-2.0, // 2
  		3.0,
  		4.0,  // 3
  		2.0,
  		NaN,  // 4
  		NaN
  	]);
  
  	N = floor( x.length / 2 );
  	v = snanvariancech( N, 1, x, 2 );
  
  	t.strictEqual( v, 6.25, 'returns expected value' );
  	t.end();
  });
  
  tape( 'the function supports a negative `stride` parameter', opts, function test( t ) {
  	var N;
  	var x;
  	var v;
  	var i;
  
  	x = new Float32Array([
  		NaN,  // 4
  		NaN,
  		1.0,  // 3
  		2.0,
  		2.0,  // 2
  		-7.0,
  		-2.0, // 1
  		3.0,
  		4.0,  // 0
  		2.0
  	]);
  	N = floor( x.length / 2 );
  
  	v = snanvariancech( N, 1, x, -2 );
  	t.strictEqual( v, 6.25, 'returns expected value' );
  
  	x = new Float32Array( 1e3 );
  	for ( i = 0; i < 1e3; i++ ) {
  		x[ i ] = 100.0;
  	}
  	v = snanvariancech( x.length, 1, x, -1 );
  	t.strictEqual( v, 0.0, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'if provided a `stride` parameter equal to `0`, the function returns `0` provided the correction term is not less than `0` and the first element is not `NaN`', opts, function test( t ) {
  	var x;
  	var v;
  
  	x = new Float32Array( [ 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( x.length, 1, x, 0 );
  	t.strictEqual( v, 0.0, 'returns expected value' );
  
  	x = new Float32Array( [ NaN, 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( x.length, 1, x, 0 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	x = new Float32Array( [ 1.0, -2.0, -4.0, 5.0, 3.0 ] );
  
  	v = snanvariancech( x.length, x.length, x, 0 );
  	t.strictEqual( isnanf( v ), true, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'the function supports view offsets', opts, function test( t ) {
  	var x0;
  	var x1;
  	var N;
  	var v;
  
  	x0 = new Float32Array([
  		2.0,
  		1.0,  // 0
  		2.0,
  		-2.0, // 1
  		-2.0,
  		2.0,  // 2
  		3.0,
  		4.0,  // 3
  		6.0,
  		NaN,  // 4
  		NaN
  	]);
  
  	x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
  	N = floor(x1.length / 2);
  
  	v = snanvariancech( N, 1, x1, 2 );
  	t.strictEqual( v, 6.25, 'returns expected value' );
  
  	t.end();
  });
  