Overflow error питон

Это ошибка переполнения из-за математических операций

Ситуация: для научной диссертации по логарифмам мы пишем модуль, который будет возводить в разные степени число Эйлера — число e, которое примерно равно 2,71828. Для этого мы подключаем модуль math, где есть нужная нам команда — math.exp(), которая возводит это число в указанную степень.

Нам нужно выяснить различные значения числа в степени от 1 до 1000, чтобы потом построить график, поэтому пишем такой простой модуль:

# импортируем математический модуль
import math

# список с результатами
results = []
# перебираем числа от 1 до 1000
for i in range(1000):
    # добавляем результат в список
    results.append(math.exp(i))
    # и выводим его на экран
    print(results[i-1])

Но при запуске кода компьютер выдаёт ошибку: 

❌ OverflowError: math range error

Что это значит: компьютер во время расчётов вылез за допустимые границы переменной — ему нужно записать в неё большее значение, чем то, на которое она рассчитана.

Когда встречается: во время математических расчётов, которые приводят к переполнению выделенной для переменной памяти. При этом общий размер оперативной памяти вообще не важен — имеет значение только то, сколько байт компьютер выделил для хранения нашего конкретного значения. Если у вас, например, 32 Гб оперативной памяти, это не поможет решить проблему.

Что делать с ошибкой OverflowError: math range error

Так как это ошибка переполнения, то самая частая причина этой ошибки — попросить компьютер посчитать что-то слишком большое. 

Чтобы исправить ошибку OverflowError: math range error, есть два пути — использовать разные трюки или специальные библиотеки для вычисления больших чисел или уменьшить сами вычисления. Про первый путь поговорим в отдельной статье, а пока сделаем проще: уменьшим диапазон с 1000 до 100 чисел — этого тоже хватит для построения графика:

# импортируем математический модуль
import math

# список с результатами
results = []
# перебираем числа от 1 до 100
for i in range(100):
    # добавляем результат в список
    results.append(math.exp(i))
    # и выводим его на экран
    print(results[i-1])

A programmer in Python encounters many errors, one of which is ‘overflowerror: math range error.’ This error happens because any variable which acts as an operand and holds data in any form has a maximum limit to store the data. Thus, when the program written by the programmer tries to exceed those limits in any arithmetic or mathematical or any other operation, we get ‘overflowerror: math range error’. Nevertheless, there are ways you can deal with this error, and we will discuss those ways in this article.

Let us see an example of ‘overflowerror: math range error’ to understand how this error occurs. We will take an example in which we write a simple code for carrying out the calculation of exponential value.

import math
x = int(input("Enter value of x: "))
y = math.exp(x)
print(y)

Output:

Enter value of x: 2000
Traceback (most recent call last):
  File "C:testcode.py", line 3, in <module>
    y = math.exp(x)
OverflowError: math range error

As you can see from the above example, we have declared a variable ‘x’ and assigned a value to it by taking user input. Further, we use this variable as the exponential power. Although the value computed in this case is way more than a variable can hold, the data type limit is 709, and we have exceeded the limit by taking 2000. Therefore this code throws an ‘overflowerror: math range error’. So now we have seen how this error occurs. Further, let’s see how you can solve this kind of error.

Using Try/Except To Solve Overflowerror: Math Range Error

‘Overflowerror: math range error’ is an exception type of error and we can use try/except to handle this exception. Exception type of errors arises after passing our code syntax, or basically, we can say exception errors occur during runtime. ‘Try’ and ‘except’ allows us to handle exceptions in our code. ‘Try’ and ‘except’ is somehow similar to ‘if’ and ‘else’ in some way, but it instead checks if an exception arises in the code and executes the code accordingly. Further if no exception arises, the ‘try’ clause is executed, and if exceptions arise ‘except’ clause is executed.

So eventually, we can use ‘try’ and ‘except’ to solve this error, to understand how to let us know with the help of an example.

import math
x = int(input("Enter value of x: "))
try:
	y = math.exp(x)
except OverflowError:
	y = float('inf')
    print("x value should not exceed 709")
print(y)

Output:

Enter value of x: 2000
x value should not exceed 709
inf

In the above example, we have written the same code which carries out exponential calculations. Although in this code, there is no error thrown because of the ‘try’ and ‘except’ clauses. The ‘try’ clause checks if the code raises any exception after we enter the value of ‘x’ as 2000. The data type limit is 709. Therefore, an exception will arise, and the ‘except’ clause will execute.

Using Numpy Library

The numpy library in Python is vastly used when dealing with mathematical data and programs. Numpy library does not raise an exception when a program tries to operate at a capacity exceeding the data-type limit. Therefore we can use numpy to execute our code without throwing an error.

import numpy as np
x = int(input("Enter value of x: "))
y = np.exp(x)
print(y) 

Output:

Enter value of x: 2000
inf

From the code output, you can see that numpy gives ‘inf’ as output without raising an exception. It only raises a warning during runtime but executes code without error.

Using If/else For Solving Overflowerror: Math Range Error

You can also use ‘if’ and ‘else’ statements to check if your code will raise an exception beforehand the exception raises. When we use the if/else statement to solve this error, we are not letting the exception be raised by setting up a loop that checks if the value exceeds the data-type limit and only executes the mathematical operator if it is not. Let us make it more clear to understand using an example.

import math
x = int(input("Enter value of x: "))
if (x < 709)
    y = math.exp(x)
    print(y)
else
    print("x value should not exceed 709")

Output:

Enter value of x: 2000
x value should not exceed 709

From the example code, you can see when we enter the value of ‘x’ in input, the ‘if’ statement checks if it is less than 709. Thus it only executes the if statement and calculates the exponential value if the value of ‘x’ is less than 709. However, it prints “x value should not exceed 709” if the value is greater than 709. Therefore you can see that we only execute the mathematical operation after checking the criteria that signify if the program will raise an exception or not.

Solving Overflowerror In ‘Math.pow()’ Function

This error can also occur when we are using the ‘math.pow()’ function. ‘pow()’ function allows you to carry out exponential calculations, it takes two variables as arguments where one is the base variable, and the other is exponential variable. Therefore this function can throw ‘overflowerror: math range error’ if the exponential variable is much greater and the calculation results in exceeding the data-type limit.

import math
x = int(input("Enter the base variable: "))
y = int(input("Enter the exponential variable: "))
calculation = math.pow(x, y)
print(calculation)

Output:

Enter the base variable: 3
Enter the exponential variable: 1000
  File "C:testcodetwo.py", line 3, in <module>
    calculation = math.pow(x, y)
OverflowError: math range error

As you can see from the example code above, if the exponential variable is much more significant and the calculation exceeds the data-type limit, it raises an exception. You can solve this error by using any of the methods discussed earlier in this article, for example:

import math
x = int(input("Enter the base variable: "))
y = int(input("Enter the exponential variable: "))
try:
	calculation = math.pow(x, y)
except OverflowError:
	calculation = float('inf')
    print("base variable value should not exceed 709")
print(calculation)

How To Avoid Overflow Errors?

So far in the article, we have seen how you can handle the ‘overflow error,’ but it is far better to avoid errors in your program if possible to ensure smooth and desired execution. To prevent overflow errors, you need to keep these points in your mind:

• Be aware of the mathematical and arithmetic operator’s input data-type limits.
• Have a general idea about the calculations and their sizes to be performed in the code so you can avoid raising an error.
• Use operators who are suitable and capable of handling your calculations efficiently.

FAQs

Conclusion

Finally, we have seen various ways to solve ‘overflowerror: math range error’ in Python. You can use any of the methods which you desire or that your code permits you to use. However, it is best to avoid errors when writing a code because error-free code always provides the best results.

To know more about other ‘OverflowError: Python int too large to convert to C long’ type of error and how to solve it, check this post.