How to Solve Equations with java ?

Question

Hi guys,

according to below 3 Equations

x+y+z=100; x+y-z=50; x-y-z=10;

how to get the value of x,y,z with java?

=============================================

String equation1="x+y+z=100;";
String equation2="x+y-z=50;";
String equation3="x-y-z=10;";

int[] SolveEquations(equation1,equation2,equation3){

// to do
//how to do ?

}

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or do you hava other solutions or other common frameworks ? thanks .

Answer 1

You can use determinant to calculate values of x y and z. Logic can be found out here http://www.intmath.com/Matrices-determinants/1%5FDeterminants.php

And then you need to implement it in java using 3 dimensional arrays.

Answer 2

Another source, with sample code in various languages is given here

Answer 3

Create a parser using ANTLR. Then evaluate the AST using Gaussian elimination.

Answer 4

Use Gaussian_elimination it's incredibly easy, but there are some values you may have hard life calculating.

Code example

Answer 5

Since you're writing Java, you can use the JAMA package to solve this. I'd recommend a good LU decomposition method.

It's a simple linear algebra problem. You should be able to solve it by hand or using something like Excel pretty easily. Once you have that you can use the solution to test your program.

There's no guarantee, of course, that there is a solution. If your matrix is singular, that means there is no intersection of those three lines in 3D space.

Answer 6

You can also use Commons Math. They have a section of this in their userguide (see 3.4)