newderivative = oldvalue - newvalue ;
secondderivative = oldderivative - newderivative ;
oldderivative = newderivative ; // Remembers the previous one
Yes that should work.
Also, is:
index = index % LMSIZE;More efficient than:
index++ ;
if (index >= LMSIZE) index = 0 ; // If LMSIZE is 16 index cannot be more than 15
No, shorter source code does not always mean shorter exe or faster runtime.
The modulo is a division which is one of the most expensive basic math operations.
Yes, please post the code, you want to share, I'll comment (maybe others too 