fixed-point

I am using Anthony Williams' fixed point library described in the Dr Dobb's article " Optimizing Math-Intensive Applications with Fixed-Point Arithmetic " to calculate the distance between two geographical points using the Rhumb Line method . This works well enough when the distance between the points is significant (greater than a few kilometers), but is very poor at smaller distances. The worst case being when the two points are equal or near equal, the result is a distance of 194 meters, while I need precision of at least 1 metre at distances >= 1 metre. By comparison with a double

I am trying to create an application that stores stock prices with high precision. Currently I am using a double to do so. To save up on memory can I use any other data type? I know this has something to do with fixed point arithmetic, but I can't figure it out. The idea behind fixed-point arithmetic is that you store the values multiplied by a certain amount, use the multiplied values for all calculus, and divide it by the same amount when you want the result. The purpose of this technique is to use integer arithmetic (int, long...) while being able to represent fractions. The usual and most

I've got a fixed point class (10.22) and I have a need of a pow, a sqrt, an exp and a log function. Alas I have no idea where to even start on this. Can anyone provide me with some links to useful articles or, better yet, provide me with some code? I'm assuming that once I have an exp function then it becomes relatively easy to implement pow and sqrt as they just become. pow( x, y ) => exp( y * log( x ) ) sqrt( x ) => pow( x, 0.5 ) Its just those exp and log functions that I'm finding difficult (as though I remember a few of my log rules, I can't remember much else about them). Presumably,

I want to store 3.50 into a mysql table. I have a float that I store it in, but it stores as 3.5, not 3.50. How can I get it to have the trailing zero? Morfildur Do not store money values as float, use the DECIMAL or NUMERIC type: Documentation for MySQL Numeric Types EDIT & clarification: Float values are vulnerable to rounding errors are they have limited precision so unless you do not care that you only get 9.99 instead of 10.00 you should use DECIMAL/NUMERIC as they are fixed point numbers which do not have such problems. It's not generally a good idea to store money as a float as rounding

I am looking for a free C++ fixed point library (Mainly for use with embedded devices, not for arbitrary precision math). Basically, the requirements are: No unnecessary runtime overhead: whatever can be done at compile time, should be done at compile time. Ability to transparently switch code between fixed and floating point, with no inherent overhead. Fixed point math functions. There's no much point using fixed point if you need to cast back and forth in order to take a square root. Small footprint. Any suggestions? flatmush There is an open-source fixed point math library project which can