c++ function name ambiguity

My class has two functions with the same name and the following signature:

Mat<T, rows, cols> & transpose()
{   
    for (size_t i = 0; i < rows; ++i) {
        for (size_t j = i + 1; j < cols; ++j) {
            std::swap(at(i, j), at(j, i));
        }
    }
    return *this;
}

This method does an inplace transpose of the matrix. Now, I have another function which leaves the original matrix unchanged and does the transpose in a new matrix. The signature is:

Mat<T, cols, rows> transpose() const

Note that the columns and rows are swapped.

Now, I call it as:

Mat<int, 3, 4> d;
// Fill this matrix
Mat<int, 4, 3> e = d.transpose();

This still tries to call the first method. If I rename the second method to transpose2 and call that, it is fine. Is there a way to make these two functions inambiguous?