README.md

floor2

Round a numeric value to the nearest power of two toward negative infinity.

Usage

var floor2 = require( '@stdlib/math/base/special/floor2' );

floor2( x )

Rounds a numeric value to the nearest power of two toward negative infinity.

var v = floor2( -4.2 );
// returns -8.0

v = floor2( -4.5 );
// returns -8.0

v = floor2( -4.6 );
// returns -8.0

v = floor2( 9.99999 );
// returns 8.0

v = floor2( 9.5 );
// returns 8.0

v = floor2( 13.0 );
// returns 8.0

v = floor2( -13.0 );
// returns -16.0

v = floor2( 0.0 );
// returns 0.0

v = floor2( -0.0 );
// returns -0.0

v = floor2( Infinity );
// returns Infinity

v = floor2( -Infinity );
// returns -Infinity

v = floor2( NaN );
// returns NaN

Examples

var uniform = require( '@stdlib/random/array/uniform' );
var logEachMap = require( '@stdlib/console/log-each-map' );
var floor2 = require( '@stdlib/math/base/special/floor2' );

var opts = {
    'dtype': 'float64'
};
var x = uniform( 100, -50.0, 50.0, opts );

logEachMap( 'x: %0.4f. Rounded: %d.', x, floor2 );

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C APIs

Usage

#include "stdlib/math/base/special/floor2.h"

stdlib_base_floor2( x )

Rounds a numeric value to the nearest power of two toward negative infinity.

double y = stdlib_base_floor2( -4.2 );
// returns -8.0

The function accepts the following arguments:

• x: [in] double input value.

double stdlib_base_floor2( const double x );

Examples

#include "stdlib/math/base/special/floor2.h"
#include <stdio.h>

int main( void ) {
    const double x[] = { 3.14, -3.14, 0.0, 0.0 / 0.0 };

    double y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_floor2( x[ i ] );
        printf( "floor2(%lf) = %lf\n", x[ i ], y );
    }
}

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See Also

• @stdlib/math/base/special/ceil2: round a numeric value to the nearest power of two toward positive infinity.
• @stdlib/math/base/special/floor: round a double-precision floating-point number toward negative infinity.
• @stdlib/math/base/special/floor10: round a numeric value to the nearest power of 10 toward negative infinity.
• @stdlib/math/base/special/round2: round a numeric value to the nearest power of two on a linear scale.