QR-decomposition:
random 4x3 matrix A:
    -0.503     -0.779     -0.066 
     0.543      0.315     -0.134 
    -0.292      0.888     -0.797 
     0.285     -0.943     -0.504 
matrix R:
     0.845     0.0412     0.0583 
         0       1.54     -0.147 
         0          0      0.942 
Q^T*Q:
         1  -2.78e-17   5.55e-17 
 -2.78e-17          1  -5.55e-17 
  5.55e-17  -5.55e-17          1 
Q*R:
    -0.503     -0.779     -0.066 
     0.543      0.315     -0.134 
    -0.292      0.888     -0.797 
     0.285     -0.943     -0.504 
Q*R=A, test passed