fix: correct header order, validation, style issues, and use uniform over randu

Author: Planeshifter

lib/node_modules/@stdlib/stats/base/dists/chi/pdf/benchmark/benchmark.native.js

@@ -23,7 +23,7 @@
 var resolve = require( 'path' ).resolve;
 var bench = require( '@stdlib/bench' );
 var Float64Array = require( '@stdlib/array/float64' );
-var randu = require( '@stdlib/random/base/randu' );
+var uniform = require( '@stdlib/random/base/uniform' );
 var isnan = require( '@stdlib/math/base/assert/is-nan' );
 var tryRequire = require( '@stdlib/utils/try-require' );
 var pkg = require( './../package.json' ).name;
@@ -50,8 +50,8 @@ bench( pkg + '::native', opts, function benchmark( b ) {
 	x = new Float64Array( len );
 	k = new Float64Array( len );
 	for ( i = 0; i < len; i++ ) {
-		x[ i ] = ( randu() * 20.0 ) - 10.0;
-		k[ i ] = ( randu() * 20.0 ) + 0.1;
+		x[ i ] = uniform( -10.0, 10.0 );
+		k[ i ] = uniform( 0.1, 20.1 );
 	}
 
 	b.tic();

lib/node_modules/@stdlib/stats/base/dists/chi/pdf/examples/c/example.c

@@ -37,4 +37,5 @@ int main( void ) {
 		y = stdlib_base_dists_chi_pdf( x, k );
 		printf( "x: %lf, k: %lf, f(x;k): %lf\n", x, k, y );
 	}
+	return 0;
 }

lib/node_modules/@stdlib/stats/base/dists/chi/pdf/src/addon.c

@@ -19,5 +19,4 @@
 #include "stdlib/math/base/napi/binary.h"
 #include "stdlib/stats/base/dists/chi/pdf.h"
 
-// cppcheck-suppress shadowFunction
 STDLIB_MATH_BASE_NAPI_MODULE_DD_D( stdlib_base_dists_chi_pdf )

lib/node_modules/@stdlib/stats/base/dists/chi/pdf/src/main.c

@@ -16,12 +16,12 @@
 * limitations under the License.
 */
 
+#include "stdlib/stats/base/dists/chi/pdf.h"
 #include "stdlib/constants/float64/pinf.h"
 #include "stdlib/math/base/assert/is_nan.h"
 #include "stdlib/math/base/special/exp.h"
 #include "stdlib/math/base/special/gamma.h"
 #include "stdlib/math/base/special/pow.h"
-#include "stdlib/stats/base/dists/chi/pdf.h"
 
 /**
 * Evaluates the probability density function (PDF) for a Chi distribution with degrees of freedom `k` at a value `x`.
@@ -37,7 +37,7 @@
 double stdlib_base_dists_chi_pdf( const double x, const double k ) {
 	double out;
 	double kh;
-	if ( stdlib_base_is_nan( x ) || stdlib_base_is_nan( k ) || k <= 0.0 ) {
+	if ( stdlib_base_is_nan( x ) || stdlib_base_is_nan( k ) || k < 0.0 ) {
 		return 0.0 / 0.0; // NaN
 	}
 	if ( k == 0.0 ) {