Java BigDecimal trigonometric methods

java precision trigonometry bigdecimal
Marco picture Marco · Jan 31, 2010 · Viewed 11.1k times · Source

I am developing a mathematical parser which is able to evaluate String like '5+b*sqrt(c^2)'. I am using ANTLR for the parsing and make good progress. Now I fell over the Java class BigDecimal and thought: hey, why not thinking about precision here.

My problem is that the Java API does not provide trigonometric methods for BigDecimals like java.lang.Math. Do you know if there are any good math libraries like Apache Commons out there that deal with this problem?

The other questions is how to realize the power method so that I can calculate 4.9 ^ 1.4 with BigDecimals. Is this possible?

A book request about numerical computing is also appreciated.

Answer

Scott Fines picture Scott Fines · Jan 31, 2010

ApFloat is a library which contains arbitrary-precision approximations of trigometric functions and non-integer powers both; however, it uses its own internal representations, rather than BigDecimal and BigInteger. I haven't used it before, so I can't vouch for its correctness or performance characteristics, but the api seems fairly complete.

Related questions

Retain precision with double in Java

public class doublePrecision { public static void main(String[] args) { double total = 0; total += 5.6; total += 5.8; System.out.println(total); } } The above code prints: 11.399999999999 How would I get this to just print (or be able to use it as) 11.4?

Read More
How to convert milliseconds to seconds with precision

I want to convert milliseconds to seconds (for example 1500ms to 1.5s, or 500ms to 0.5s) with as much precision as possible. Double.parseDouble(500 / 1000 + "." + 500 % 1000); isn't the best way to do it: I'm looking for a way to get the remainder …

Read More
Convert Java Number to BigDecimal : best way

I am looking for the best way to convert a Number to a BigDecimal. Is this good enough? Number number; BigDecimal big = new BigDecimal(number.toString()); Can we lose precision with the toString() method ?

Read More