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 Float64Array = require( '@stdlib/array/float64' );
  var tryRequire = require( '@stdlib/utils/try-require' );
  
  
  // VARIABLES //
  
  var dscal = tryRequire( resolve( __dirname, './../lib/ndarray.native.js' ) );
  var opts = {
  	'skip': ( dscal instanceof Error )
  };
  
  
  // TESTS //
  
  tape( 'main export is a function', opts, function test( t ) {
  	t.ok( true, __filename );
  	t.strictEqual( typeof dscal, 'function', 'main export is a function' );
  	t.end();
  });
  
  tape( 'the function has an arity of 5', opts, function test( t ) {
  	t.strictEqual( dscal.length, 5, 'has expected arity' );
  	t.end();
  });
  
  tape( 'the function multiplies `x` by a constant', opts, function test( t ) {
  	var expected;
  	var x;
  
  	x = new Float64Array([
  		4.0,
  		2.0,
  		-3.0,
  		5.0,
  		-1.0,
  		2.0,
  		-5.0,
  		6.0
  	]);
  	expected = new Float64Array([
  		20.0,
  		10.0,
  		-15.0,
  		25.0,
  		-5.0,
  		10.0,
  		-25.0,
  		30.0
  	]);
  
  	dscal( x.length, 5.0, x, 1, 0 );
  	t.deepEqual( x, expected, 'returns expected value' );
  
  	x = new Float64Array( [ 1.0, 2.0 ] );
  	expected = new Float64Array( [ 5.0, 10.0 ] );
  
  	dscal( x.length, 5.0, x, 1, 0 );
  	t.deepEqual( x, expected, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'the function returns a reference to the input array', opts, function test( t ) {
  	var out;
  	var x;
  
  	x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
  	out = dscal( x.length, 3.0, x, 1, 0 );
  
  	t.strictEqual( out, x, 'same reference' );
  	t.end();
  });
  
  tape( 'if provided an `N` parameter less than or equal to `0`, the function returns `x` unchanged', opts, function test( t ) {
  	var expected;
  	var x;
  
  	x = new Float64Array( [ 3.0, -4.0, 1.0 ] );
  	expected = new Float64Array( [ 3.0, -4.0, 1.0 ] );
  
  	dscal( 0, 1.0, x, 1, 0 );
  	t.deepEqual( x, expected, 'returns expected value' );
  
  	dscal( -4, 1.0, x, 1, 0 );
  	t.deepEqual( x, expected, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'if `alpha` equals `1`, the function returns `x` unchanged', opts, function test( t ) {
  	var expected;
  	var x;
  
  	x = new Float64Array( [ 3.0, -4.0, 1.0, 15.0, 4.0, 3.0 ] );
  	expected = new Float64Array( [ 3.0, -4.0, 1.0, 15.0, 4.0, 3.0 ] );
  
  	dscal( x.length, 1.0, x, 1, 0 );
  	t.deepEqual( x, expected, 'returns expected value' );
  
  	t.end();
  });
  
  tape( 'the function supports specifying a stride', opts, function test( t ) {
  	var expected;
  	var x;
  
  	x = new Float64Array([
  		2.0,  // 0
  		-3.0,
  		-5.0, // 1
  		7.0,
  		6.0   // 2
  	]);
  	expected = new Float64Array([
  		10.0,  // 0
  		-3.0,
  		-25.0, // 1
  		7.0,
  		30.0   // 2
  	]);
  
  	dscal( 3, 5.0, x, 2, 0 );
  	t.deepEqual( x, expected, 'returns expected value' );
  	t.end();
  });
  
  tape( 'the function supports specifying a negative stride', opts, function test( t ) {
  	var expected;
  	var x;
  
  	x = new Float64Array([
  		2.0,  // 2
  		-3.0,
  		-5.0, // 1
  		7.0,
  		6.0   // 0
  	]);
  	expected = new Float64Array([
  		10.0,  // 2
  		-3.0,
  		-25.0, // 1
  		7.0,
  		30.0   // 0
  	]);
  
  	dscal( 3, 5.0, x, -2, x.length-1 );
  	t.deepEqual( x, expected, 'returns expected value' );
  	t.end();
  });
  
  tape( 'the function supports an offset parameter', opts, function test( t ) {
  	var expected;
  	var x;
  
  	x = new Float64Array([
  		1.0,
  		2.0, // 0
  		3.0,
  		4.0, // 1
  		5.0,
  		6.0  // 2
  	]);
  	expected = new Float64Array([
  		1.0,
  		10.0,
  		3.0,
  		20.0,
  		5.0,
  		30.0
  	]);
  
  	dscal( 3, 5.0, x, 2, 1 );
  	t.deepEqual( x, expected, 'returns expected value' );
  	t.end();
  });
  
  tape( 'if `stride` is equal to `1`, the function efficiently multiplies `x` by a constant', opts, function test( t ) {
  	var expected;
  	var alpha;
  	var x;
  	var i;
  
  	alpha = 3.0;
  	x = new Float64Array( 100 );
  	expected = new Float64Array( x.length );
  	for ( i = 0; i < x.length; i++ ) {
  		x[ i ] = i;
  		expected[ i ] = x[ i ] * alpha;
  	}
  	dscal( x.length, alpha, x, 1, 0 );
  	t.deepEqual( x, expected, 'returns expected value' );
  
  	x = new Float64Array( 240 );
  	expected = new Float64Array( x.length );
  	for ( i = 0; i < x.length; i++ ) {
  		x[ i ] = i;
  		expected[ i ] = x[ i ] * alpha;
  	}
  	dscal( x.length, alpha, x, 1, 0 );
  	t.deepEqual( x, expected, 'returns expected value' );
  
  	t.end();
  });
  