How to solve linear system of equations using colt library in java

Question

I want to solve the linear equation matrix*X=D using Colt library. I tried :

DoubleMatrix2D matrix;
matrix = new DenseDoubleMatrix2D(4,4);
for (int row = 0; row < 4; row++) {
    for (int column = 0; column < 4; column++) {
        // We set and get a cell value:             
        matrix.set(row,column,row+column);          
    }
}
DoubleMatrix2D D;
D = new DenseDoubleMatrix2D(4,1);
D.set(0,0, 1.0);
D.set(1,0, -1.0);
D.set(2,0, 91.0);
D.set(3,0, -5.0);
DoubleMatrix2D X;
X = solve(matrix,D);

but I get an error
"The method solve(DoubleMatrix2D, DoubleMatrix2D) is undefined for the type Test" , where Test is the name of the class.

What have I done wrong? Any ideas?...

Answer 1

The reason why you are getting this error is because method solve() is non-static and can't be accessed from main().

This should solve your problem:

Algebra algebra = new Algebra();
DoubleMatrix2D X = algebra.solve(matrix, D);