using System;

namespace Science.Mathematics.LinearAlgebra
{
    public class FactorizationAeqQH
    {
        private Matrix Q;
        private Matrix H;
        private Matrix a;
        public FactorizationAeqQH(Matrix A)
        {
            a = A;
            Q = new Matrix(A.SizeOfRow,A.SizeOfColumn);
            H = new Matrix(A.SizeOfColumn, A.SizeOfColumn);
        }
        public void Compute()
        {
            FactorizationAeqUSVt obj = new FactorizationAeqUSVt(a);
            obj.Compute();
            Matrix UVt = obj.ColumnOrthogonal * obj.Orthogonal.Transpose;
            Matrix VSVt = obj.Orthogonal * obj.Diagonal * obj.Orthogonal.Transpose;

            for (int i = 0; i < a.SizeOfRow; i++)
            {
                for (int j = 0; j < a.SizeOfColumn; j++)
                {
                    Q[i, j] = UVt[i, j];                    
                }
            }
            for (int i = 0; i < a.SizeOfColumn; i++)
            {
                for (int j = 0; j < a.SizeOfColumn; j++)
                {
                    H[i, j] = VSVt[i, j];
                }
            } 
        }
        public Matrix Orthogonal
        {
            get { return Q; }
        }
        public Matrix PositiveSemidefinite
        {
            get { return H; }
        }
    }
}