Python: OverflowError: math range error
Question:
I get a Overflow error when i try this calculation, but i cant figure out why.
1-math.exp(-4*1000000*-0.0641515994108)
Answers:
The number you’re asking math.exp to calculate has, in decimal, over 110,000 digits. That’s slightly outside of the range of a double, so it causes an overflow.
This may give you a clue why:
http://www.wolframalpha.com/input/?i=math.exp%28-4*1000000*-0.0641515994108%29
Notice the 111442 exponent.
I think the value gets too large to fit into a double in python which is why you get the OverflowError. The largest value I can compute the exp of on my machine in Python is just sligthly larger than 709.78271.
To fix it use:
try:
ans = math.exp(200000)
except OverflowError:
ans = float('inf')
Try np.exp() instead of math.exp()
Numpy handles overflows more gracefully, np.exp(999) results in inf
and 1. / (1. + np.exp(999)) therefore simply results in zero
import math
import numpy as np
print(1-np.exp(-4*1000000*-0.0641515994108))
Unfortunately, no one explained what the real solution was. I solved the problem using:
from mpmath import *
You can find the documentation below:
I get a Overflow error when i try this calculation, but i cant figure out why.
1-math.exp(-4*1000000*-0.0641515994108)
The number you’re asking math.exp to calculate has, in decimal, over 110,000 digits. That’s slightly outside of the range of a double, so it causes an overflow.
This may give you a clue why:
http://www.wolframalpha.com/input/?i=math.exp%28-4*1000000*-0.0641515994108%29
Notice the 111442 exponent.
I think the value gets too large to fit into a double in python which is why you get the OverflowError. The largest value I can compute the exp of on my machine in Python is just sligthly larger than 709.78271.
To fix it use:
try:
ans = math.exp(200000)
except OverflowError:
ans = float('inf')
Try np.exp() instead of math.exp()
Numpy handles overflows more gracefully, np.exp(999) results in inf
and 1. / (1. + np.exp(999)) therefore simply results in zero
import math
import numpy as np
print(1-np.exp(-4*1000000*-0.0641515994108))
Unfortunately, no one explained what the real solution was. I solved the problem using:
from mpmath import *
You can find the documentation below: