feat(negative-binomial-variance): adding code required for negative binomial variance

Author: Aadish Jain

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

@@ -22,7 +22,6 @@
 
 var bench = require( '@stdlib/bench' );
 var Float64Array = require( '@stdlib/array/float64' );
-var uniform = require( '@stdlib/random/array/uniform' );
 var randu = require( '@stdlib/random/base/randu' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var floor = require( '@stdlib/math/base/special/floor' );
@@ -62,21 +61,18 @@ bench(pkg, function benchmark(b) {
 	b.end();
 });
 
-bench(pkg + ':factory', function benchmark(b) {
-	var myvariance;
+bench(pkg + ':direct', function benchmark(b) {
 	var r;
 	var p;
 	var y;
 	var i;
-	var x = uniform(100, 1.0, 10.0);
 
 	r = 5;
 	p = 0.5;
-	myvariance = variance.factory(r, p);
 
 	b.tic();
 	for (i = 0; i < b.iterations; i++) {
-		y = myvariance(x[i % x.length]);
+		y = variance(r, p);
 		if (isnan(y)) {
 			b.fail('should not return NaN');
 		}