def _estimate_from_amount(self, from_token, to_token, to_desired_amount):
max_error = 3e-15
exchange_contract = self._find_exchange_contract(from_token, to_token)
conversion_func = self._get_conversion_function(exchange_contract, from_token, to_token)
def root_func(x):
return conversion_func(x) - to_desired_amount
x_lower, y_lower, x_upper, y_upper = find_monotonic_increasing_bounds(root_func, to_desired_amount)
new_x, new_y = false_position_method(
root_func,
x_lower, y_lower,
x_upper, y_upper,
max_error, max_iterations=6)
return new_x, new_y + to_desired_amount
def test_find_monotonic_increasing_bounds(root_func, guess, root):
x_lower, y_lower, x_upper, y_upper = find_monotonic_increasing_bounds(
root_func, guess)
assert x_lower <= root
assert x_upper >= root