basis_mat = C.eval_basis(x)

        Evaluates self's basis functions on x and returns them stacked
        in a matrix. basis_mat[i,j] gives basis function i evaluated at
        x[j,:].

def eval_basis(self, x, regularize=True):
        """
        basis_mat = C.eval_basis(x)

        Evaluates self's basis functions on x and returns them stacked
        in a matrix. basis_mat[i,j] gives basis function i evaluated at
        x[j,:].
        """
        if regularize:
            x = regularize_array(x)

        out = zeros((self.n, x.shape[0]), dtype=float, order='F')

        for i in xrange(self.n):
            out[i] = self.basis[i](x, **self.params)

        return out