Relative error: not able to get the right answer.

Hi. I am not able to get the correct value of the relative error. Grateful if you please help.

real val approx val relative error

7000 7000 0

5261 5160 1.92

4657 4869 -4.03

Matlab code:

tval = [7000 5261 4657]'

fcast = [7000 5160 4869 ]'

eabs = (tval-fcast)

erel = eabs/tval*100

Ans:

erel =

0 0 0 0 0

1.2625e+000 0 0 0 0

-2.6500e+000 0 0 0 0

Thank you

Answer 1

[Star Strider]

You need to do element-wise division:

erel = eabs./tval*100
           ↑          

Then it comes close tho the result you want.