/cont-frac

Continued Fractions

Primary LanguageJavaScriptCreative Commons Zero v1.0 UniversalCC0-1.0

Continued Fractions

Run it at https://xin-xin.me/code/cont-frac/

This program makes it easy to study continued fractions.

Usage

There are 4 sections: (frac | dec | func | cont)

Take note that if you switch sections, your data in the previous section will be lost!

frac

This converts a normal fraction into a continued fraction. Input the numerator and denominator as two integers. (ex. 1578275893 / 2987598372947)

If you type a / in the first box, it automatically switches to the second box.

In all sections, nprec is the number of decimal places for the decimal number output.

dec

This converts a decimal number into a continued fraction. Input a number like 2.718281828459045235360287471353

func

This uses two Javascript functions to generate the partial numerators and partial denominators of a generalized continued fraction. In this program, a(n) are the numerators and b(n) are the denominators so that the final number is

a(0) + b(1) / (a(1) + b(2) / (a(2) + ...))

To run the program, click inside the nprec box, and press Enter or change the number.

For example, this gives the golden ratio

a(n)

return 1;

b(n)

return 1;

This gives Euler's number e:

a(n)

if (n == 0)return 2;
if (n % 3 == 1)return 1;
if (n % 3 == 2)return ((n+1)/3)*2;
if (n % 3 == 0)return 1;

b(n)

return 1;

cont

This converts a continued fraction into a regular fraction and a decimal number.

It takes continued fraction in a form like this:

[0; 1, 2, 3, 4, 5, 6, 7, 8, 9]

Whitespace and square brackets are optional. Either ; or , can be used as delimiters.

That means that this works just as well:

0,   1,2, 3 ,4 , 5, 6,7 ,8,9  ]

License

This program is dedicated to the public domain using the Creative Commons CC0. See LICENSE.txt for details.