refactor!: modify C implementation to accept double instead of int32 in math/base/special/factorial2

lib/node_modules/@stdlib/math/base/special/factorial2/README.md

@@ -124,16 +124,16 @@ for ( i = 0; i < values.length; i++ ) {
 Evaluates the [double factorial][double-factorial] of `n`.
 
 ```c
-double out = stdlib_base_factorial2( 3 );
-// returns 3
+double out = stdlib_base_factorial2( 3.0 );
+// returns 3.0
 ```
 
 The function accepts the following arguments:
 
--   **n**: `[in] int32_t` input value.
+-   **n**: `[in] double` input value.
 
 ```c
-double stdlib_base_factorial2( const int32_t n );
+double stdlib_base_factorial2( const double n );
 ```
 
 </section>
@@ -157,16 +157,15 @@ double stdlib_base_factorial2( const int32_t n );
 ```c
 #include "stdlib/math/base/special/factorial2.h"
 #include <stdio.h>
-#include <stdint.h>
 
 int main( void ) {
-    const int32_t x[] = { 1, 10, 100, 301, 302 };
+    const double x[] = { 1.0, 10.0, 100.0, 301.0, 302.0 };
 
     double b;
     int i;
     for ( i = 0; i < 5; i++ ){
         b = stdlib_base_factorial2( x[ i ] );
-        printf ( "factorial2(%d) = %lf\n", x[ i ], b );
+        printf ( "factorial2(%lf) = %lf\n", x[ i ], b );
     }
 }
 ```

lib/node_modules/@stdlib/math/base/special/factorial2/benchmark/c/native/benchmark.c

@@ -92,14 +92,14 @@ static double rand_double( void ) {
 */
 static double benchmark( void ) {
 	double elapsed;
-	int32_t x;
+	double x;
 	double y;
 	double t;
 	int i;
 
 	t = tic();
 	for ( i = 0; i < ITERATIONS; i++ ) {
-		x = (int32_t)(rand_double() * 301);
+		x = round( rand_double() * 301.0 );
 		y = stdlib_base_factorial2( x );
 		if ( y != y ) {
 			printf( "should not return NaN\n" );

lib/node_modules/@stdlib/math/base/special/factorial2/examples/c/example.c

@@ -18,15 +18,14 @@
 
 #include "stdlib/math/base/special/factorial2.h"
 #include <stdio.h>
-#include <stdint.h>
 
 int main( void ) {
-	const int32_t x[] = { 1, 10, 100, 301, 302 };
+	const double x[] = { 1.0, 10.0, 100.0, 301.0, 302.0 };
 
 	double b;
 	int i;
 	for ( i = 0; i < 5; i++ ) {
 		b = stdlib_base_factorial2( x[ i ] );
-		printf ( "factorial2(%d) = %lf\n", x[ i ], b );
+		printf ( "factorial2(%lf) = %lf\n", x[ i ], b );
 	}
 }

lib/node_modules/@stdlib/math/base/special/factorial2/include/stdlib/math/base/special/factorial2.h

@@ -19,8 +19,6 @@
 #ifndef STDLIB_MATH_BASE_SPECIAL_FACTORIAL2_H
 #define STDLIB_MATH_BASE_SPECIAL_FACTORIAL2_H
 
-#include <stdint.h>
-
 /*
 * If C++, prevent name mangling so that the compiler emits a binary file having undecorated names, thus mirroring the behavior of a C compiler.
 */
@@ -31,7 +29,7 @@ extern "C" {
 /**
 * Evaluates the double factorial of `n`.
 */
-double stdlib_base_factorial2( const int32_t n );
+double stdlib_base_factorial2( const double n );
 
 #ifdef __cplusplus
 }

lib/node_modules/@stdlib/math/base/special/factorial2/manifest.json

@@ -39,7 +39,8 @@
         "@stdlib/math/base/napi/unary",
         "@stdlib/math/base/assert/is-even",
         "@stdlib/constants/float64/pinf",
-        "@stdlib/constants/float64/max-nth-double-factorial"
+        "@stdlib/constants/float64/max-nth-double-factorial",
+        "@stdlib/math/base/assert/is-integer"
       ]
     },
     {
@@ -55,7 +56,8 @@
       "dependencies": [
         "@stdlib/math/base/assert/is-even",
         "@stdlib/constants/float64/pinf",
-        "@stdlib/constants/float64/max-nth-double-factorial"
+        "@stdlib/constants/float64/max-nth-double-factorial",
+        "@stdlib/math/base/assert/is-integer"
       ]
     },
     {
@@ -71,7 +73,8 @@
       "dependencies": [
         "@stdlib/math/base/assert/is-even",
         "@stdlib/constants/float64/pinf",
-        "@stdlib/constants/float64/max-nth-double-factorial"
+        "@stdlib/constants/float64/max-nth-double-factorial",
+        "@stdlib/math/base/assert/is-integer"
       ]
     }
   ]

lib/node_modules/@stdlib/math/base/special/factorial2/src/addon.c

@@ -19,4 +19,4 @@
 #include "stdlib/math/base/special/factorial2.h"
 #include "stdlib/math/base/napi/unary.h"
 
-STDLIB_MATH_BASE_NAPI_MODULE_I_D( stdlib_base_factorial2 )
+STDLIB_MATH_BASE_NAPI_MODULE_D_D( stdlib_base_factorial2 )

lib/node_modules/@stdlib/math/base/special/factorial2/src/main.c

@@ -18,42 +18,42 @@
 
 #include "stdlib/math/base/special/factorial2.h"
 #include "stdlib/math/base/assert/is_even.h"
+#include "stdlib/math/base/assert/is_integer.h"
 #include "stdlib/constants/float64/pinf.h"
 #include "stdlib/constants/float64/max_nth_double_factorial.h"
-#include <stdint.h>
 
 /**
 * Evaluates the double factorial of `n`.
 *
-* @param x         input value
+* @param n         input value
 * @return          double factorial
 *
 * @example
-* double v = stdlib_base_factorial2( 3 );
-* // returns 3
+* double v = stdlib_base_factorial2( 3.0 );
+* // returns 3.0
 */
-double stdlib_base_factorial2( const int32_t n ) {
-	int32_t last;
+double stdlib_base_factorial2( const double n ) {
+	double last;
 	double out;
-	int32_t v;
-	int32_t i;
+	double v;
+	double i;
+	if ( !stdlib_base_is_integer( n ) || n < 0.0 ) {
+		return 0.0 / 0.0; // NaN
+	}
 	if ( n > STDLIB_CONSTANT_FLOAT64_MAX_NTH_DOUBLE_FACTORIAL ) {
 		return STDLIB_CONSTANT_FLOAT64_PINF;
 	}
-	if ( n < 0 ) {
-		return 0.0/0.0;
-	}
 	v = n;
-	if ( v == 0 || v == 1 ) {
-		return 1;
+	if ( v == 0.0 || v == 1.0 ) {
+		return 1.0;
 	}
 	if ( stdlib_base_is_even( v ) ) {
-		last = 2;
+		last = 2.0;
 	} else {
-		last = 3;
+		last = 3.0;
 	}
-	out = 1;
-	for ( i = v; i >= last; i -= 2 ) {
+	out = 1.0;
+	for ( i = v; i >= last; i -= 2.0 ) {
 		out *= i;
 	}
 	return out;