@stdlib/math-base-special-fast-pow-int
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0.0.7 • Public • Published

Exponential Function

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Exponential function.

The exponential function is defined as

Exponential function

where b is the base and x is the exponent.

Installation

npm install @stdlib/math-base-special-fast-pow-int

Usage

var pow = require( '@stdlib/math-base-special-fast-pow-int' );

pow( base, exponent )

Evaluates the exponential function given a signed 32-bit integer exponent.

var v = pow( 2.0, 3 );
// returns 8.0

v = pow( 100.0, 0 );
// returns 1.0

v = pow( 3.14, 1 );
// returns 3.14

v = pow( -3.14, 1 );
// returns -3.14

v = pow( 2.0, -2 );
// returns 0.25

v = pow( NaN, 3 );
// returns NaN

Notes

  • This implementation is not recommended for high-precision applications due to error accumulation. As a trivial example, consider

    var v = pow( 10.0, 308 );
    // returns 1.0000000000000006e+308

    where the expected result is 1.0e+308.

  • If provided a negative exponent, the implementation first computes the reciprocal of the base and then evaluates the exponential function. This can introduce significant error. For example,

    var v = pow( -459, -98 );
    // returns 1.3878956588399783e-261

    where the expected result is 1.3878956588399598e-261. From the bit sequences,

    0000100111000101110110100000000111001011001011010001000101010110
    0000100111000101110110100000000111001011001011010001000100000100
    

    one observes that the returned value differs in the last 7 bits of the significand.

Examples

var pow = require( '@stdlib/math-base-special-fast-pow-int' );

var x;
var y;
var v;

x = 10.0;
for ( y = 0; y < 309; y++ ) {
    v = pow( x, y );
    console.log( '%d^%d = %d', x, y, v );
}

See Also


Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

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License

See LICENSE.

Copyright

Copyright © 2016-2022. The Stdlib Authors.

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  • stdlib-bot
  • kgryte
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  • rreusser