solve(a, b)

Solve a linear matrix equation, or system of linear scalar equations.

Computes the “exact” solution, x, of the well-determined, i.e., full rank, linear matrix equation ax = b.

  • a ((.., M, M) ndarray) – Coefficient matrix.

  • b ({(.., M,), (.., M, K)}, ndarray) – Ordinate or “dependent variable” values.


x – Solution to the system a x = b. Returned shape is identical to b.

Return type

{(.., M,), (.., M, K)} ndarray


MXNetError – If a is singular or not square.


Broadcasting rules apply, see the numpy.linalg documentation for details.

The solutions are computed using LAPACK routine _gesv.

a must be square and of full-rank, i.e., all rows (or, equivalently, columns) must be linearly independent; if either is not true, use lstsq for the least-squares best “solution” of the system/equation.


Solve the system of equations 3 * x0 + x1 = 9 and x0 + 2 * x1 = 8:

>>> a = np.array([[3,1], [1,2]])
>>> b = np.array([9,8])
>>> x = np.linalg.solve(a, b)
>>> x
array([2.,  3.])

Check that the solution is correct:

>>> np.allclose(, x), b)