How to calculate the energy of details and approxmiations coefficients of discret wavelet transform ?

Hi everyone, i calculate the energy of details and approxmiations coefficients of discret wavelet transform .i used DWT(Daub4) Here is the code

 for n=1:23
     deriv=(val(n,:))/2.559375;
    t=(0:length(deriv)-1)/Fs;
    result{n} = filtfilt(d1,deriv);
 [c,l]=wavedec(result{n},4,'db4');
    [cd1,cd2,cd3,cd4]=detcoef(c,l,[1,2,3,4]);
    cA4=appcoef(c,l,'db4',4);
    [Ea,Ed]=wenergy(c,l)
    energie{n} = {Ea, Ed};
  end
And when i was looking for the formula of the energy i found this :

and as i understand the energy is the percentage of energy corresponding to the approximation and the details

So when i was trying to write a C code using this formula and the values of cd1,cd2,cd3,cd4 i don't get the same values that i have with matlab So i want to know where i wrong ?

i mean to calcuate the energy i should use [cd1,cd2,cd3,cd4]??

Please i need a clarification,Thanks

[Ewunate Assaye Kassaw]

hello sir

it gives me a hint thanks for that

i have questions

1. n stands for what?
2. 2.559375 where this number comes from?
3. deriv=(val(n,:))/2.559375; i dont undrstand 'val' it gives error when i run it and says fix val with eval and again gives me error

can you help me please?

Answer 1

[Jiaxin Tu]

That's because wenergy gives the percentage of power out of 100.

If you divide your calculations with the formula by the sum of energy *100 you will get the same answer

Answer 2

[Ewunate Assaye Kassaw]

hello sir

it gives me a hint thanks for that

i have questions

1. n stands for what?
2. 2.559375 where this number comes from?
3. deriv=(val(n,:))/2.559375; i dont undrstand 'val' it gives error when i run it and says fix val with eval and again gives me error

can you help me please?