fix: change implementation to clear all test

Author: Jaysukh-409

lib/node_modules/@stdlib/stats/base/dists/planck/pmf/lib/factory.js

@@ -24,6 +24,7 @@ var isNonNegativeInteger = require( '@stdlib/math/base/assert/is-nonnegative-int
 var constantFunction = require( '@stdlib/utils/constant-function' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var exp = require( '@stdlib/math/base/special/exp' );
+var expm1 = require( '@stdlib/math/base/special/expm1' );
 
 
 // MAIN //
@@ -60,15 +61,11 @@ function factory( lambda ) {
 	* // returns <number>
 	*/
 	function pmf( x ) {
-		var temp1;
-		var temp2;
 		if ( isnan( x ) ) {
 			return NaN;
 		}
 		if ( isNonNegativeInteger( x ) ) {
-			temp1 = exp( -lambda );
-			temp2 = exp( -lambda * x );
-			return ( 1 - temp1 ) * temp2;
+			return -expm1( -lambda ) * exp( -lambda * x );
 		}
 		return 0.0;
 	}

lib/node_modules/@stdlib/stats/base/dists/planck/pmf/lib/main.js

@@ -23,6 +23,7 @@
 var isNonNegativeInteger = require( '@stdlib/math/base/assert/is-nonnegative-integer' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var exp = require( '@stdlib/math/base/special/exp' );
+var expm1 = require( '@stdlib/math/base/special/expm1' );
 
 
 // MAIN //
@@ -60,15 +61,11 @@ var exp = require( '@stdlib/math/base/special/exp' );
 * // returns NaN
 */
 function pmf( x, lambda ) {
-	var temp1;
-	var temp2;
 	if ( isnan( x ) || isnan( lambda ) || lambda < 0.0 ) {
 		return NaN;
 	}
 	if ( isNonNegativeInteger( x ) ) {
-		temp1 = exp( -lambda );
-		temp2 = exp( -lambda * x );
-		return ( 1 - temp1 ) * temp2;
+		return -expm1( -lambda ) * exp( -lambda * x );
 	}
 	return 0.0;
 }