Doubt about the entries for calculating the matricial equation Ax = b

Newbie
1

Hi!
In my program, I have to solve a matricial equation of the type M*a = ra. Where the entries are the Matrix M (10 * 10) and the vector ra. I read the chapter 16.6 Matrix Decompositions and I found the command TVectorD Solve(const TVectorD &b,Bool_t &ok) which is the most direct manner to calculate the solution. But how to add the matrix A as a parameter of the command Solve. In this example there is only the vector b as the function argument? Do I have to apply the LU decompostion before in the M matrix?

Is that the correct way to solve the matricial equation M*a = ra?

TDecompLU lu(M);
   Bool_t ok;
   lu.Solve(ra,ok);
2

Solve is a method of the decomposition class and returns a TVectorD solution.
So in your case do:

   TDecompLU lu(M);
   Bool_t ok;
   const TVectorD a = lu.Solve(ra,ok);