normalizef
Return a normal number
yand exponentexpsatisfyingx = y * 2^exp.
Usage
var normalizef = require( '@stdlib/number/float32/base/normalize' );
normalizef( x )
Returns a normal number y and exponent exp satisfying x = y * 2^exp.
var toFloat32 = require( '@stdlib/number/float64/base/to-float32' );
var out = normalizef( toFloat32( 1.401e-45 ) );
// returns [ 1.1754943508222875e-38, -23 ]
By default, the function returns y and exp as a two-element array.
var toFloat32 = require( '@stdlib/number/float64/base/to-float32' );
var pow = require( '@stdlib/math/base/special/pow' );
var out = normalizef( toFloat32( 1.401e-45 ) );
// returns [ 1.1754943508222875e-38, -23 ]
var y = out[ 0 ];
var exp = out[ 1 ];
var bool = ( y*pow(2, exp) === toFloat32(1.401e-45) );
// returns true
The function expects a finite, non-zero single-precision floating-point number x. If x == 0,
var out = normalizef( 0.0 );
// returns [ 0.0, 0 ];
If x is either positive or negative infinity or NaN,
var PINF = require( '@stdlib/constants/float32/pinf' );
var NINF = require( '@stdlib/constants/float32/ninf' );
var out = normalizef( PINF );
// returns [ Infinity, 0 ]
out = normalizef( NINF );
// returns [ -Infinity, 0 ]
out = normalizef( NaN );
// returns [ NaN, 0 ]
normalizef( x, out, stride, offset )
Returns a normal number y and exponent exp satisfying x = y * 2^exp and assigns results to a provided output array.
var toFloat32 = require( '@stdlib/number/float64/base/to-float32' );
var Float32Array = require( '@stdlib/array/float32' );
var out = new Float32Array( 2 );
var v = normalizef.assign( toFloat32( 1.401e-45 ), out, 1, 0 );
// returns <Float32Array>[ 1.1754943508222875e-38, -23 ]
var bool = ( v === out );
// returns true
Notes
- While the function accepts higher precision floating-point numbers, beware that providing such numbers can be a source of subtle bugs as the relation
x = y * 2^expmay not hold.
Examples
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var pow = require( '@stdlib/math/base/special/pow' );
var toFloat32 = require( '@stdlib/number/float64/base/to-float32' );
var normalizef = require( '@stdlib/number/float32/base/normalize' );
var frac;
var exp;
var x;
var v;
var i;
// Generate denormalized single-precision floating-point numbers and then normalize them...
for ( i = 0; i < 100; i++ ) {
frac = randu() * 10.0;
exp = 38 + round( randu()*6.0 );
x = frac * pow( 10.0, -exp );
x = toFloat32( x );
v = normalizef( x );
console.log( '%d = %d * 2^%d = %d', x, v[0], v[1], v[0]*pow(2.0, v[1]) );
}
C APIs
Usage
#include "stdlib/number/float32/base/normalize.h"
stdlib_base_float32_normalize( x, *y, *exp )
Returns a normal number y and exponent exp satisfying x = y * 2^exp.
#include <stdint.h>
float y;
int32_t exp;
stdlib_base_float32_normalize( 3.14, &y, &exp );
The function accepts the following arguments:
- x:
[in] floatinput value. - y:
[out] float*destination for normal number. - exp:
[out] int32_t*destination for exponent.
void stdlib_base_float32_normalize( const float x, float *y, int32_t *exp );
Examples
#include "stdlib/number/float32/base/normalize.h"
#include <stdint.h>
#include <stdio.h>
int main( void ) {
float x[] = { 4.0f, 0.0f, -0.0f, 1.0f, -1.0f, 3.14f, -3.14f, 1.0e-38f, -1.0e-38f, 1.0f/0.0f, -1.0f/0.0f, 0.0f/0.0f };
int32_t exp;
float y;
int i;
for ( i = 0; i < 12; i++ ) {
stdlib_base_float32_normalize( x[ i ], &y, &exp );
printf( "%f => y: %f, exp: %" PRId32 "\n", x[ i ], y, exp );
}
}