@stdlib/math-base-special-truncsd

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truncsd

Round a numeric value to the nearest number toward zero with n significant figures.

Installation

npm install @stdlib/math-base-special-truncsd

Usage

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

truncsd( x, n, b )

Rounds a numeric value to the nearest number toward zero with n significant figures.

var v = truncsd( 3.141592653589793, 5, 10 );
// returns 3.1415

v = truncsd( 3.141592653589793, 1, 10 );
// returns 3.0

v = truncsd( 12368.0, 2, 10 );
// returns 12000.0

v = truncsd( 0.0313, 2, 2 );
// returns 0.03125

Examples

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

var opts = {
    'dtype': 'float64'
};
var x = uniform( 100, -5000.0, 5000.0, opts );

logEachMap( 'x: %0.4f. a: %d. b: %d. Rounded: %0.4f.', x, 5, 10, truncsd );

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C APIs

Usage

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

stdlib_base_truncsd( x, n, b )

Rounds a numeric value to the nearest number toward negative infinity with n significant figures.

double out = stdlib_base_truncsd( 3.141592653589793, 5, 10 );
// returns 3.1415

The function accepts the following arguments:

• x: [in] double input value.
• n: [in] int32_t number of significant figures.
• b: [in] int32_t base.

double stdlib_base_truncsd( const double x, const int32_t n, const int32_t b );

Examples

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

int main( void ) {
    const double x[] = { -5.0, -3.89, -2.78, -1.67, -0.56, 0.56, 1.67, 2.78, 3.89, 5.0 };
    const int32_t n[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
    const int32_t b[] = { 20, 19, 18, 17, 16, 15, 14, 13, 12, 11 };

    double v;
    int i;
    for ( i = 0; i < 10; i++ ) {
        v = stdlib_base_truncsd( x[ i ], n[ i ], b[ i ] );
        printf( "truncsd(%lf, %d, %d) = %lf\n", x[ i ], n[ i ], b[ i ], v );
    }
}

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See Also

• @stdlib/math-base/special/ceilsd: round a numeric value to the nearest number toward positive infinity with N significant figures.
• @stdlib/math-base/special/floorsd: round a numeric value to the nearest number toward negative infinity with N significant figures.
• @stdlib/math-base/special/roundsd: round a double-precision floating-point number to the nearest value with N significant figures.
• @stdlib/math-base/special/trunc: round a double-precision floating-point number toward zero.

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Notice

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.

Community

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License

See LICENSE.

Copyright

Copyright 2016-2026. The Stdlib Authors.