normalize
Return a normal number
yand exponentexpsatisfyingx = y * 2^exp.
Usage
var normalize = require( '@stdlib/number/float64/base/normalize' );
normalize( x )
Returns a normal number y and exponent exp satisfying x = y * 2^exp.
var pow = require( '@stdlib/math/base/special/pow' );
var out = normalize( 3.14e-319 );
// returns [ 1.4141234400356668e-303, -52 ]
var y = out[ 0 ];
var exp = out[ 1 ];
var bool = ( y*pow(2.0, exp) === 3.14e-319 );
// returns true
The function expects a finite, non-zero numeric value x. If x == 0,
var out = normalize( 0.0 );
// returns [ 0.0, 0 ];
If x is either positive or negative infinity or NaN,
var PINF = require( '@stdlib/constants/float64/pinf' );
var NINF = require( '@stdlib/constants/float64/ninf' );
var out = normalize( PINF );
// returns [ Infinity, 0 ]
out = normalize( NINF );
// returns [ -Infinity, 0 ]
out = normalize( NaN );
// returns [ NaN, 0 ]
normalize.assign( 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 Float64Array = require( '@stdlib/array/float64' );
var out = new Float64Array( 2 );
var v = normalize.assign( 3.14e-319, out, 1, 0);
// returns <Float64Array>[ 1.4141234400356668e-303, -52 ]
var bool = ( v === out );
// returns true
Examples
var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
var randu = require( '@stdlib/random/base/uniform' );
var pow = require( '@stdlib/math/base/special/pow' );
var normalize = require( '@stdlib/number/float64/base/normalize' );
var frac;
var exp;
var x;
var v;
var i;
// Generate denormalized numbers and then normalize them...
for ( i = 0; i < 100; i++ ) {
// Generate a random fraction:
frac = randu( 0.0, 10.0 );
// Generate an exponent on the interval (-308,-324):
exp = discreteUniform( -323, -309 );
// Create a subnormal number (~2.23e-308, ~4.94e-324):
x = frac * pow( 10.0, exp );
// Determine a `y` and an `exp` to "normalize" the subnormal:
v = normalize( 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/float64/base/normalize.h"
stdlib_base_float64_normalize( x, *y, *exp )
Returns a normal number y and exponent exp satisfying x = y * 2^exp.
#include <stdint.h>
double y;
int32_t exp;
stdlib_base_float64_normalize( 3.14, &y, &exp );
The function accepts the following arguments:
- x:
[in] doubleinput value. - y:
[out] double*destination for normal number. - exp:
[out] int32_t*destination for exponent.
void stdlib_base_float64_normalize( const double x, double *y, int32_t *exp );
Examples
#include "stdlib/number/float64/base/normalize.h"
#include <stdint.h>
#include <stdio.h>
#include <inttypes.h>
int main( void ) {
double x[] = { 1.0, 3.14, 0.0, -0.0, 3.14e-308, 3.14e308, 1.0/0.0, 0.0/0.0 };
int32_t exp;
double y;
int i;
for ( i = 0; i < 8; i++ ) {
stdlib_base_float64_normalize( x[ i ], &y, &exp );
printf( "%lf => y: %lf, exp: %" PRId32 "\n", x[ i ], y, exp );
}
}