bench: refactor random number generation in stats/base/dists/poisson

PR-URL: #5106
Closes: #4984

Reviewed-by: Philipp Burckhardt <pburckhardt@outlook.com>

Author: pranav-1720

lib/node_modules/@stdlib/stats/base/dists/poisson/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 Float64Array = require( '@stdlib/array/float64' );
+var uniform = require( '@stdlib/random/base/uniform' );
+var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var pkg = require( './../package.json' ).name;
 var cdf = require( './../lib' );
@@ -32,15 +33,21 @@ var cdf = require( './../lib' );
 
 bench( pkg, function benchmark( b ) {
 	var lambda;
+	var len;
 	var x;
 	var y;
 	var i;
 
+	len = 100;
+	lambda = new Float64Array( len );
+	x = new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = discreteUniform( 1, 100 );
+		lambda[ i ] = uniform( 0.0, 100.0 );
+	}
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		x = ceil( randu()*100.0 );
-		lambda = ( randu()*100.0 );
-		y = cdf( x, lambda );
+		y = cdf( x[ i % len ], lambda[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}
@@ -56,17 +63,21 @@ bench( pkg, function benchmark( b ) {
 bench( pkg+':factory', function benchmark( b ) {
 	var lambda;
 	var mycdf;
+	var len;
 	var x;
 	var y;
 	var i;
 
 	lambda = 10.0;
 	mycdf = cdf.factory( lambda );
-
+	len = 100;
+	x= new Float64Array( len );
+	for ( i = 0; i < len; i++ ) {
+		x[ i ] = discreteUniform( 1, 50 );
+	}
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		x = ceil( randu()*50.0 );
-		y = mycdf( x );
+		y = mycdf( x[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}