How to realize exp() function or sigmoid() function

[maxxu]

Hi

   I want to implement the sigmoid function，but, It appears that the function does not exist in the library，

   I use the Automotive Math and Motor Control Library Set for NXP MC9S12ZVM devices.

   Does the exp()function exist in the library? or，How should I implement it with other tools

   This algorithm, I hope to have as fast calculation speed as possible。

                                                                                                thank you 

[pachamatej · Accepted solution]

Hello,

if you don't care about CPU load, then I would follow standard programming patterns for math implementation. Otherwise, I'd recommend to calculate a lookup table offline (e.g. using MS Excel) and then use it in the MCU. Polynomial approximation is also an option. The two techniques mentioned can be realized with support of the AMMCLib (GFLIB_Lut1D and MLIB functions such as Mul, Add, etc.).

Best regards,

Matej

[maxxu]

Can someone help me？