topic How to realize exp() function or sigmoid() function in S12 / MagniV Microcontrollers

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

maxxu — Sat, 05 Jun 2021 08:49:02 GMT

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

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

maxxu — Fri, 11 Jun 2021 06:15:09 GMT

Can someone help me？

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

pachamatej — Wed, 16 Jun 2021 08:13:54 GMT

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