# How to tell Mathematica to do all calculations in a notebook numerically?

I would like to tell mathematica to do all calculations numerically.

I have already replaced my input by adding a dot in the end, for example :

nAvg=10.


But the thing is that sometimes I will have summation on discrete integers. It is not necesseraly to put all my code but just to give an idea, terms lile :

Sum[Cos[Omegan[n]*t/2]^2*Abs[cn[n]]^2, {n, nMinSum[nAvg],
nMaxSum[nAvg]}]


Here the n in the sum is a discrete indice. How to tell to mathematica to use it in a numeric rather than symbolic way ?

And if this number is actually multiplied by some numerical number (it is actually the case in this specific example), does mathematica knows that he has to convert everything in numeric ?

• In this case, isn't NSum what you want? You not only have to worry about constants as you mention, but functions that are closed form versus numeric. – Moo Jun 21 at 17:27
• @Moo Ok I will try to use numerical oriented functions. Actually I tried to used NSum but it returned me an error I didn't understand where Sum worked instead. But I guess I would need to open another question for this. – StarBucK Jun 21 at 17:29
• Technically you can set \$Pre = N – Fortsaint Jun 21 at 20:15