import sympy


def DefineMatrix(name, m, n):
    """
    This method defines a symbolic matrix.

    Keyword arguments:
    - name -- Name of variables.
    - m -- Number of rows.
    - n -- Number of columns.
    """
    return sympy.Matrix(m, n, lambda i, j: sympy.var("{name}_{i}_{j}".format(name=name, i=i, j=j)))