decimal.Context.power()

power(x, y, modulo=None)

Return x to the power of y, reduced modulo modulo if given.

With two arguments, compute x**y. If x is negative then y must be integral. The result will be inexact unless y is integral and the result is finite and can be expressed exactly in ‘precision’ digits. The rounding mode of the context is used. Results are always correctly-rounded in the Python version.

With three arguments, compute (x**y) % modulo. For the three argument form, the following restrictions on the arguments hold:

• all three arguments must be integral
• y must be nonnegative
• at least one of x or y must be nonzero
• modulo must be nonzero and have at most ‘precision’ digits

The value resulting from Context.power(x, y, modulo) is equal to the value that would be obtained by computing (x**y) % modulo with unbounded precision, but is computed more efficiently. The exponent of the result is zero, regardless of the exponents of x, y and modulo. The result is always exact.