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Compute an integer binary logarithm.
npm install @stdlib/math-base-special-fast-uint32-log2var log2Uint32 = require( '@stdlib/math-base-special-fast-uint32-log2' );Returns an approximate binary logarithm of an unsigned 32-bit integer x.
var v = log2Uint32( 4 >>> 0 );
// returns 2
v = log2Uint32( 8 >>> 0 );
// returns 3
v = log2Uint32( 9 >>> 0 );
// returns 3- This implementation provides a performance boost when an application requires only approximate computations for integer arguments.
- For applications requiring high-precision, this implementation is never suitable.
var log2Uint32 = require( '@stdlib/math-base-special-fast-uint32-log2' );
var v;
var i;
for ( i = 1; i < 101; i++ ) {
v = log2Uint32( i >>> 0 );
console.log( 'log2(%d) ≈ %d', i, v );
}#include "stdlib/math/base/special/fast/uint32_log2.h"Returns an approximate binary logarithm of an unsigned 32-bit integer x.
#include <stdint.h>
uint32_t out = stdlib_base_fast_uint32_log2( 4 );
// returns 2
out = stdlib_base_fast_uint32_log2( 9 );
// returns 3The function accepts the following arguments:
-
x:
[in] uint32_tinput value.
uint32_t stdlib_base_fast_uint32_log2( const uint32_t x );#include "stdlib/math/base/special/fast/uint32_log2.h"
#include <stdio.h>
#include <stdint.h>
int main( void ) {
const uint32_t x[] = { 5, 7, 10, 22, 98 };
uint32_t y;
int i;
for ( i = 0; i < 5; i++ ) {
y = stdlib_base_fast_uint32_log2( x[ i ] );
printf( "uint32_log2(%u) = %u\n", x[ i ], y );
}
}-
@stdlib/math-base/special/log2: binary logarithm (base 2).
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.
See LICENSE.
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