Exponential of very large number

28 visualizzazioni (ultimi 30 giorni)
Teshome Kumsa
Teshome Kumsa il 28 Ago 2021
Commentato: Steven Lord il 28 Ago 2021
Hello all! I was trying to calculate exponental of some vectors. Actually my vector has very big entries(each entries are Stresses accumulated during earquakes. That is why they are very big).
For example
exp([-235628865.417257 29372700213.5032]/10.^5)
It returns ans=
0 Inf
I need a comment on it.
  1 Commento
Matt J
Matt J il 28 Ago 2021
It wouldn't make sense to take exp() to any greater precision unless you are going to take the log of it later.

Accedi per commentare.

Risposte (1)

Chunru
Chunru il 28 Ago 2021
Modificato: Chunru il 28 Ago 2021
Those number are beyond the scope of double numbers. You can try vpa. Alternatively, keep track of the mantisa and exponent yourself as follows:
a=log10(exp(1))*([-235628865.417257 29372700213.5032]/10.^5);
aint = ceil(a);
afrac = a -aint;
xm = 10.^afrac;
xe = aint;
xstr = xm(:)+" x 10 ^ "+xe(:)
xstr = 2×1 string array
"0.47516 x 10 ^ -1023" "0.1038 x 10 ^ 127565"
  3 Commenti
Chunru
Chunru il 28 Ago 2021
The code uses your edited numbers now.
Steven Lord
Steven Lord il 28 Ago 2021
What are you hoping to do with those answers? Are you planning on dividing them by exp(x) for some other value of large magnitude?

Accedi per commentare.

Categorie

Scopri di più su Historical Contests in Help Center e File Exchange

Prodotti

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by