refactor: rename variables and reorder conditionals

Signed-off-by: Athan <[email protected]>

Author: kgryte

lib/node_modules/@stdlib/stats/base/dists/skew-normal/pdf/lib/main.js

@@ -20,8 +20,8 @@
 
 // MODULES //
 
-var normalPdf = require( '@stdlib/stats/base/dists/normal/pdf' );
-var normalCdf = require( '@stdlib/stats/base/dists/normal/cdf' );
+var normalPDF = require( '@stdlib/stats/base/dists/normal/pdf' );
+var normalCDF = require( '@stdlib/stats/base/dists/normal/cdf' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 
 
@@ -77,15 +77,15 @@ var isnan = require( '@stdlib/math/base/assert/is-nan' );
 function pdf( x, mu, sigma, alpha ) {
 	var pdf;
 	var cdf;
-	pdf = normalPdf( x, mu, sigma );
+	if ( isnan( alpha ) ) {
+		return NaN;
+	}
+	pdf = normalPDF( x, mu, sigma );
 	if ( alpha === 0.0 ) {
 		return pdf;
 	}
-	if ( isnan(alpha) ) {
-		return NaN;
-	}
-	cdf = normalCdf( alpha * x, alpha * mu, sigma );
-	return 2 * pdf * cdf;
+	cdf = normalCDF( alpha*x, alpha*mu, sigma );
+	return 2.0 * pdf * cdf;
 }