bigfloat

bigfloat is a fast arbitrary precision math library optimized for computational geometry and geoinformatics. It provides base 2 floating point:

• conversion from JavaScript number type x = new BigFloat(123.456)
• addition x.add(y)
• subtraction x.sub(y)
• multiplication x.mul(y)
• comparison x.deltaFrom(y)
• conversion to string in base 2, 10 or 16 x.toString(10)

without ever losing any significant bits. Numbers are immutable, so all operations return a new BigFloat.

Internally numbers are represented in 32-bit limbs (digits in base 2^32) somewhat like in the GMP library. The least significant limb is stored first, because basic algorithms for arithmetic operations progress from the least to most significant digit while propagating carry. If carry causes the output to grow, adding a new limb at the end of the array is faster than adding it in the beginning.

bigfloat is optimized for exponents relatively close to zero, so the location of the decimal point is always present in the limb array, even if that introduces otherwise insignificant leading or trailing zero digits.

Getting started

git clone https://github.com/charto/bigfloat.git node_modules/bigfloat
cd node_modules/bigfloat && npm install
cd ../..
node

OR

npm install bigfloat
node

THEN

x = Math.pow(2, 53);
console.log(x + 1 - x); // Prints 0

BigFloat = require('bigfloat').BigFloat;
console.log(new BigFloat(x).add(1).sub(x).toString()); // Prints 1

License

The MIT License

Copyright (c) 2015 BusFaster Ltd