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

This commit updates the signature of the C API to accept a double rather than int32. The rationale was so that users get the same results/behavior in both JavaScript and C. This arose in the context of ufuncs, where the diverging type signatures meant differences in what dtypes would be permissible. Instead, we decided to unify and ensure the behavior is consistent.

BREAKING CHANGE: update signature to accept doubles

User code should behave similarly in the primary case of providing integer-valued input values. However, no longer will real-values truncate. Now, real-valued inputs will result in `NaN`, which is, arguably, better behavior, as real-to-integer truncation can be a source of silent bugs.

PR-URL: #7953
Co-authored-by: Athan Reines <[email protected]>
Reviewed-by: Athan Reines <[email protected]>

Author: gunjjoshi

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

@@ -191,19 +191,19 @@ for ( i = 0; i > -79; i-- ) {
 Computes the nth [negaFibonacci number][fibonacci-number].
 
 ```c
-double out = stdlib_base_negafibonacci( 0 );
-// returns 0
+double out = stdlib_base_negafibonacci( 0.0 );
+// returns 0.0
 
-out = stdlib_base_negafibonacci( -1 );
-// returns 1
+out = stdlib_base_negafibonacci( -1.0 );
+// returns 1.0
 ```
 
 The function accepts the following arguments:
 
--   **n**: `[in] int32_t` input value.
+-   **n**: `[in] double` input value.
 
 ```c
-double stdlib_base_negafibonacci( const int32_t n );
+double stdlib_base_negafibonacci( const double n );
 ```
 
 </section>
@@ -227,15 +227,14 @@ double stdlib_base_negafibonacci( const int32_t n );
 ```c
 #include "stdlib/math/base/special/negafibonacci.h"
 #include <stdio.h>
-#include <stdint.h>
 
 int main( void ) {
-    int32_t i;
+    double i;
     double v;
 
-    for ( i = 0; i > -79; i-- ) {
+    for ( i = 0.0; i > -79.0; i-- ) {
         v = stdlib_base_negafibonacci( i );
-        printf( "negafibonacci(%d) = %lf\n", i, v );
+        printf( "negafibonacci(%lf) = %lf\n", i, v );
     }
 }
 ```

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

@@ -91,13 +91,13 @@ static double rand_double( void ) {
 */
 static double benchmark( void ) {
 	double elapsed;
-	int32_t x[ 100 ];
+	double x[ 100 ];
 	double t;
 	double y;
 	int i;
 
 	for ( i = 0; i < 100; i++ ) {
-		x[ i ] = (int32_t)floor( 40.0 * rand_double() );
+		x[ i ] = floor( 40.0 * rand_double() );
 	}
 
 	t = tic();

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

@@ -18,14 +18,13 @@
 
 #include "stdlib/math/base/special/negafibonacci.h"
 #include <stdio.h>
-#include <stdint.h>
 
 int main( void ) {
-	int32_t i;
+	double i;
 	double v;
 
-	for ( i = 0; i > -79; i-- ) {
+	for ( i = 0.0; i > -79.0; i-- ) {
 		v = stdlib_base_negafibonacci( i );
-		printf( "negafibonacci(%d) = %lf\n", i, v );
+		printf( "negafibonacci(%lf) = %lf\n", i, v );
 	}
 }

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

@@ -19,8 +19,6 @@
 #ifndef STDLIB_MATH_BASE_SPECIAL_NEGAFIBONACCI_H
 #define STDLIB_MATH_BASE_SPECIAL_NEGAFIBONACCI_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" {
 /**
 * Computes the nth negaFibonacci number.
 */
-double stdlib_base_negafibonacci( const int32_t n );
+double stdlib_base_negafibonacci( const double n );
 
 #ifdef __cplusplus
 }

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

@@ -38,7 +38,8 @@
       "dependencies": [
         "@stdlib/math/base/napi/unary",
         "@stdlib/constants/float64/max-safe-nth-fibonacci",
-        "@stdlib/math/base/special/abs"
+        "@stdlib/math/base/special/abs",
+        "@stdlib/math/base/assert/is-integer"
       ]
     },
     {
@@ -53,7 +54,8 @@
       "libpath": [],
       "dependencies": [
         "@stdlib/constants/float64/max-safe-nth-fibonacci",
-        "@stdlib/math/base/special/abs"
+        "@stdlib/math/base/special/abs",
+        "@stdlib/math/base/assert/is-integer"
       ]
     },
     {
@@ -68,7 +70,8 @@
       "libpath": [],
       "dependencies": [
         "@stdlib/constants/float64/max-safe-nth-fibonacci",
-        "@stdlib/math/base/special/abs"
+        "@stdlib/math/base/special/abs",
+        "@stdlib/math/base/assert/is-integer"
       ]
     }
   ]

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

@@ -20,4 +20,4 @@
 #include "stdlib/math/base/napi/unary.h"
 #include<stdint.h>
 
-STDLIB_MATH_BASE_NAPI_MODULE_I_D( stdlib_base_negafibonacci )
+STDLIB_MATH_BASE_NAPI_MODULE_D_D( stdlib_base_negafibonacci )

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

@@ -17,8 +17,10 @@
 */
 
 #include "stdlib/math/base/special/negafibonacci.h"
+#include "stdlib/math/base/assert/is_integer.h"
 #include "stdlib/math/base/special/abs.h"
 #include "stdlib/constants/float64/max_safe_nth_fibonacci.h"
+#include <stdlib.h>
 
 static const double negafibonacci_value[ 79 ] = {
 	0.0,
@@ -109,17 +111,17 @@ static const double negafibonacci_value[ 79 ] = {
 * @return     output value
 *
 * @example
-* double out = stdlib_base_negafibonacci( -1 );
-* // returns 1
+* double out = stdlib_base_negafibonacci( -1.0 );
+* // returns 1.0
 */
-double stdlib_base_negafibonacci( const int32_t n ) {
-	int32_t an;
-	if ( n > 0 ) {
+double stdlib_base_negafibonacci( const double n ) {
+	double an;
+	if ( !stdlib_base_is_integer( n ) || n > 0.0 ) {
 		return 0.0 / 0.0; // NaN
 	}
 	an = stdlib_base_abs( n );
 	if ( an > STDLIB_CONSTANT_FLOAT64_MAX_SAFE_NTH_FIBONACCI ) {
 		return 0.0 / 0.0; // NaN
 	}
-	return negafibonacci_value[ an ];
+	return negafibonacci_value[ (size_t)an ];
 }