floor10

Round a numeric value to the nearest power of 10 toward negative infinity.

Usage

var floor10 = require( '@stdlib/math/base/special/floor10' );

floor10( x )

Rounds a numeric value to the nearest power of 10 toward negative infinity.

var v = floor10( -4.2 );
// returns -10.0

v = floor10( -4.5 );
// returns -10.0

v = floor10( -4.6 );
// returns -10.0

v = floor10( 9.99999 );
// returns 1.0

v = floor10( 9.5 );
// returns 1.0

v = floor10( 13.0 );
// returns 10.0

v = floor10( -13.0 );
// returns -100.0

v = floor10( 0.0 );
// returns 0.0

v = floor10( -0.0 );
// returns -0.0

v = floor10( Infinity );
// returns Infinity

v = floor10( -Infinity );
// returns -Infinity

v = floor10( NaN );
// returns NaN

Notes

The function may not return accurate results for subnormals due to a general loss in precision.
```
var v = floor10( 1.0e-323 ); // should return 1.0e-323
// returns 0.0
```

Examples

var randu = require( '@stdlib/random/base/randu' );
var floor10 = require( '@stdlib/math/base/special/floor10' );

var x;
var v;
var i;

for ( i = 0; i < 100; i++ ) {
    x = (randu()*100.0) - 50.0;
    v = floor10( x );
    console.log( 'Value: %d. Rounded: %d.', x, v );
}

C APIs

Usage

#include "stdlib/math/base/special/floor10.h"

stdlib_base_floor10( x )

Rounds a numeric value to the nearest power of 10 toward negative infinity.

double y = stdlib_base_floor10( -4.2 );
// returns -10.0

The function accepts the following arguments:

x: [in] double input value.

double stdlib_base_floor10( const double x );

Examples

#include "stdlib/math/base/special/floor10.h"
#include <stdio.h>

int main( void ) {
    const double x[] = { 3.14, -3.14, 0.0, 9.0 / 0.0 };

    double y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_floor10( x[ i ] );
        printf( "floor10(%lf) = %lf\n", x[ i ], y );
    }
}