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fpm
A C++ header-only fixed-point math library. "fpm" stands for "fixed-point math".
It is designed to serve as a drop-in replacement for floating-point types and aims to provide as much of the standard library's functionality as possible with exclusively integers. fpm
requires C++11 or higher.
fpm
is designed to guard against accidental conversion to and from floats and supports many of the standard C++ maths functions, including trigonometry, power and logarithmic functions, with performance and accuracy generally comparable to alternative libraries.
Why use fixed-point math?
There are several reasons why you can not or choose not to use floating-point math, but still want a similar type:
- Your target platform lacks an FPU, does not support floating-point operations or its floating-point operations are considerably slower than fixed-point integer operations.
- You require deterministic calculations.
If any of these reasons apply for you, and your problem domain has a clearly outlined range and required resolution, then fixed-point numbers might be a solution for you.
Quick Start
To use fpm
, include its header <fpm/fixed.hpp>
and use the fpm::fixed_16_16
, fpm::fixed_24_8
or fpm::fixed_8_24
types as if they were native floating-pointer types:
#include <fpm/fixed.hpp> // For fpm::fixed_16_16
#include <fpm/math.hpp> // For fpm::cos
#include <fpm/ios.hpp> // For fpm::operator<<
#include <iostream> // For std::cin, std::cout
int main() {
std::cout << "Please input a number: ";
fpm::fixed_16_16 x;
std::cin >> x;
std::cout << "The cosine of " << x << " radians is: " << cos(x) << std::endl;
return 0;
}
To use the fixed-point equivalents of the <math.h>
functions such as sqrt
, sin
and log
, include the header <fpm/math.hpp>
.
To stream fixed-point values to or from streams, include the header <fpm/ios.hpp>
.
Documentation
Please refer to the documentation for detailed information how to use fpm
, or skip straight to the performance or accuracy results.
Contributions
This library is a work-in-progress. We welcome any contributions that improve the functional coverage or the performance or accuracy of the mathematical functions.
License
See the LICENSE file