// check tall matrix
CommonOps.transpose(A);
CommonOps.transpose(A_inv);
b = new DenseMatrix64F(4,1,true,3,4,5,6);
x.reshape(2,1);
found.reshape(4,1);
CommonOps.mult(A_inv,b,x);
CommonOps.mult(A, x, found);
assertTrue(MatrixFeatures.isIdentical(b,found,1e-4));