code: public static double computeEigenValue(DMatrixRMaj A , DMatrixRMaj eigenVector )
      {
          double bottom = VectorVectorMult_DDRM.innerProd(eigenVector,eigenVector);
          double top = VectorVectorMult_DDRM.innerProdA(eigenVector,A,eigenVector);
  
          return top/bottom;
      }
docs: <p>
  Given matrix A and an eigen vector of A, compute the corresponding eigen value.  This is
  the Rayleigh quotient.<br>
  <br>
  x<sup>T</sup>Ax / x<sup>T</sup>x
  </p>
  
  
  @param A Matrix. Not modified.
  @param eigenVector An eigen vector of A. Not modified.
  @return The corresponding eigen value.