README.md

Lucas

Computes the nth Lucas number as a single-precision floating-point number.

The Lucas numbers are the integer sequence

$$2,1,3,4,7,11,18,29,47,76,123,199,322,\dots$$

The sequence is defined by the recurrence relation

$$L_n=\{\begin{array}{ll}2& \text{if}n=0\\ 1& \text{if}n=1\\ L_{n-1}+L_{n-2}& \text{if}n>1\end{array}$$

Usage

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

lucasf( n )

Computes the nth Lucas number as a single-precision floating-point number.

var v = lucasf( 0 );
// returns 2

v = lucasf( 1 );
// returns 1

v = lucasf( 2 );
// returns 3

v = lucasf( 3 );
// returns 4

v = lucasf( 34 );
// returns 12752043

If n > 34, the function returns NaN, as larger Lucas numbers cannot be safely represented in single-precision floating-point format.

var v = lucasf( 35 );
// returns NaN

If not provided a nonnegative integer value, the function returns NaN.

var v = lucasf( 3.14 );
// returns NaN

v = lucasf( -1 );
// returns NaN

If provided NaN, the function returns NaN.

var v = lucasf( NaN );
// returns NaN

Examples

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

var v;
var i;

for ( i = 0; i < 35; i++ ) {
    v = lucasf( i );
    console.log( v );
}

---

C APIs

Usage

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

stdlib_base_lucasf( n )

Computes the nth Lucas number as a single-precision floating-point number.

float out = stdlib_base_lucasf( 0 );
// returns 2.0f

out = stdlib_base_lucasf( 1 );
// returns 1.0f

The function accepts the following arguments:

• n: [in] int32_t input value.

float stdlib_base_lucasf( const int32_t n );

Examples

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

int main( void ) {
    int32_t i;
    float v;

    for ( i = 0; i < 35; i++ ) {
        v = stdlib_base_lucasf( i );
        printf( "lucasf(%d) = %f\n", i, v );
    }
}