feat: add C implementation math/base/special/expf

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

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+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2022 The Stdlib Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+-->
+
+# expf
+
+> Natural [exponential function][exponential-function] of single-precision floating-point number.
+
+<section class="intro">
+
+The natural [exponential function][exponential-function] is defined as
+
+<!-- <equation class="equation" label="eq:natural_exponential_function" align="center" raw="y = e^x" alt="Natural exponential function definition"> -->
+
+```math
+y = e^x
+```
+
+<!-- <div class="equation" align="center" data-raw-text="y = e^x" data-equation="eq:natural_exponential_function">
+    <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@117273e7c4f27b0835723c2940d9675af0e14cb7/lib/node_modules/@stdlib/math/base/special/exp/docs/img/equation_natural_exponential_function.svg" alt="Natural exponential function definition">
+    <br>
+</div> -->
+
+<!-- </equation> -->
+
+where `e` is [Euler's][@stdlib/constants/float64/e] number.
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var expf = require( '@stdlib/math/base/special/expf' );
+```
+
+#### expf( x )
+
+Evaluates the natural [exponential function][exponential-function]  of single-precision floating-point number.
+
+```javascript
+var v = expf( 4.0 );
+// returns ~54.5982
+
+v = expf( -9.0 );
+// returns ~1.234e-4
+
+v = expf( 0.0 );
+// returns 1.0
+
+v = expf( NaN );
+// returns NaN
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var randu = require( '@stdlib/random/base/randu' );
+var expf = require( '@stdlib/math/base/special/expf' );
+
+var x;
+var i;
+
+for ( i = 0; i < 100; i++ ) {
+    x = (randu()*100.0) - 50.0;
+    console.log( 'e^%d = %d', x, expf( x ) );
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- C interface documentation. -->
+
+* * *
+
+<section class="c">
+
+## C APIs
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- C usage documentation. -->
+
+<section class="usage">
+
+### Usage
+
+```c
+#include "stdlib/math/base/special/expf.h"
+```
+
+#### stdlib_base_expf( x )
+
+Evaluates the natural [exponential function][exponential-function]  of single-precision floating-point number.
+
+```c
+float out = stdlib_base_expf( 4.0 );
+// returns ~54.5982
+
+out = stdlib_base_expf( -9.0 );
+// returns ~1.234e-4
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] float` input value.
+
+```c
+float stdlib_base_exp( const float x );
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<!-- C API usage examples. -->
+
+<section class="examples">
+
+### Examples
+
+```c
+#include "stdlib/math/base/special/expf.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+int main( void ) {
+    float x;
+    float v;
+    int i;
+
+    for ( i = 0; i < 100; i++ ) {
+        x = ( (float)rand() / (float)RAND_MAX ) * 10.0;
+        v = stdlib_base_expf( x );
+        printf( "e^%f = %f\n", x, v );
+    }
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+* * *
+
+## See Also
+
+-   <span class="package-name">[`@stdlib/math/base/special/exp10`][@stdlib/math/base/special/exp10]</span><span class="delimiter">: </span><span class="description">base 10 exponential function.</span>
+-   <span class="package-name">[`@stdlib/math/base/special/exp2`][@stdlib/math/base/special/exp2]</span><span class="delimiter">: </span><span class="description">base 2 exponential function.</span>
+-   <span class="package-name">[`@stdlib/math/base/special/expm1`][@stdlib/math/base/special/expm1]</span><span class="delimiter">: </span><span class="description">compute exp(x) - 1.</span>
+-   <span class="package-name">[`@stdlib/math/base/special/ln`][@stdlib/math/base/special/ln]</span><span class="delimiter">: </span><span class="description">evaluate the natural logarithm of a double-precision floating-point number.</span>
+
+</section>
+
+<!-- /.related -->
+
+<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="links">
+
+[exponential-function]: https://en.wikipedia.org/wiki/Exponential_function
+
+[@stdlib/constants/float64/e]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/constants/float64/e
+
+<!-- <related-links> -->
+
+[@stdlib/math/base/special/exp10]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/exp10
+
+[@stdlib/math/base/special/exp2]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/exp2
+
+[@stdlib/math/base/special/expm1]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/expm1
+
+[@stdlib/math/base/special/ln]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/ln
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/math/base/special/expf/benchmark/benchmark.js

@@ -0,0 +1,72 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2018 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var bench = require( '@stdlib/bench' );
+var randu = require( '@stdlib/random/base/randu' );
+var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
+var pkg = require( './../package.json' ).name;
+var expf = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var x;
+	var y;
+	var i;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		x = ( randu()*100.0 ) - 50.0;
+		y = expf( x );
+		if ( isnanf( y ) ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( isnanf( y ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( pkg+'::built-in', function benchmark( b ) {
+	var x;
+	var y;
+	var i;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		x = ( randu()*100.0 ) - 50.0;
+		y = Math.exp( x ); // eslint-disable-line stdlib/no-builtin-math
+		if ( isnanf( y ) ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( isnanf( y ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

lib/node_modules/@stdlib/math/base/special/expf/benchmark/benchmark.native.js

@@ -0,0 +1,60 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2022 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var resolve = require( 'path' ).resolve;
+var bench = require( '@stdlib/bench' );
+var randu = require( '@stdlib/random/base/randu' );
+var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
+var tryRequire = require( '@stdlib/utils/try-require' );
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var expf = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( expf instanceof Error )
+};
+
+
+// MAIN //
+
+bench( pkg+'::native', opts, function benchmark( b ) {
+	var x;
+	var y;
+	var i;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		x = ( randu()*100.0 ) - 50.0;
+		y = expf( x );
+		if ( isnanf( y ) ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( isnanf( y ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});