usencrypt.exp

usencrypt.exp(x, n=50, debug=False)

Computes the exponential of \(x\) using \(n\) iterations of the Taylor series approximation method.

Parameters

• x (usencrypt.cipher.Float or float) – The input value.

• n (int) – The number of iterations for the Taylor series approximation method. Defaults to 50.

Returns

The exponential of x.

Return type

usencrypt.cipher.Float

Note

Using about 50 iterations of the Taylor series gives us error-free precision on the range \(−9 < x < 20\).

Warning

The total range of numbers we can represent with our 64 bits is from \(2^{-32}\) to \(2^{31}\). Ideally with the exponential, we would be able to cover calculations up to the range \(x = 22\). Currently, the series method fails to do that.

Examples

>>> import usencrypt as ue
>>> a = ue.encrypt(2.0)
>>> a_exp = ue.exp(a)
>>> a_exp
(0x7f843af52c40) Float: 0x7cda4283cad131a5d7fe9dae55a7b2a9bd5988755b61bfbae75d0f98885c32b0
>>> ue.decrypt(a_exp)
2.117000014986843