bench: refactor random number generation in stats/base/dists/negative-binomial

PR-URL: #5193
Closes: #4980

Reviewed-by: Karan Anand <[email protected]>

Author: gkbishnoi07

lib/node_modules/@stdlib/stats/base/dists/negative-binomial/cdf/benchmark/benchmark.js

@@ -21,8 +21,9 @@
 // MODULES //
 
 var bench = require( '@stdlib/bench' );
-var ceil = require( '@stdlib/math/base/special/ceil' );
-var randu = require( '@stdlib/random/base/randu' );
+var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
+var uniform = require( '@stdlib/random/base/uniform' );
+var Float64Array = require( '@stdlib/array/float64' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var EPS = require( '@stdlib/constants/float64/eps' );
 var pkg = require( './../package.json' ).name;
@@ -32,18 +33,26 @@ var cdf = require( './../lib' );
 // MAIN //
 
 bench( pkg, function benchmark( b ) {
+	var len;
 	var r;
 	var p;
 	var x;
 	var y;
 	var i;
 
+	len = 100;
+	x = new Float64Array( len );
+	r = new Float64Array( len );
+	p = new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = uniform( 0.0, 100.0 );
+		r[ i ] = discreteUniform( 1, 100 );
+		p[ i ] = uniform( EPS, 1.0 );
+	}
+
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		x = randu()*100.0;
-		r = ceil( randu()*100.0 );
-		p = ( randu()*1.0 ) + EPS;
-		y = cdf( x, r, p );
+		y = cdf( x[ i % len ], r[ i % len ], p[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}
@@ -58,6 +67,7 @@ bench( pkg, function benchmark( b ) {
 
 bench( pkg+':factory', function benchmark( b ) {
 	var mycdf;
+	var len;
 	var r;
 	var p;
 	var x;
@@ -67,11 +77,15 @@ bench( pkg+':factory', function benchmark( b ) {
 	r = 80;
 	p = 0.4;
 	mycdf = cdf.factory( r, p );
+	len = 100;
+	x = new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = uniform( 0.0, 100.0 );
+	}
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		x = ( randu()*100 );
-		y = mycdf( x );
+		y = mycdf( x[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}