Python math.erf() Method
The Python math.erf() method is used to calculate the error method. It is a mathematical method that describes the probability of an event occurring within a certain range of values in a normal distribution.
Mathematically, the error method is defined as −
$$\mathrm{erf(x)\:=\:\frac{2}{\sqrt{\pi}}\:\int^{x}_{0}\:e^{−t^{2}}\:dt}$$Where, e is the base of the natural logarithm and π is the mathematical constant pi. The error method is an odd method, meaning that erf(-x) = -erf(x) and is being bounded between -1 and 1.
Syntax
Following is the basic syntax of the Python math.erf() method −
math.erf(x)
Parameters
This method accepts a real number or a numeric expression as a parameter for which you want to calculate the error method.
Return Value
The method returns the value of the error method evaluated at x.
Example 1
In the following example, we are calculating the error method for a positive real number using the math.erf() method −
import math
x = 1.5
result = math.erf(x)
print("Error method for x =", x, ":", result)
Output
The output obtained is as follows −
Error method for x = 1.5 : 0.9661051464753108
Example 2
In here, we are calculating the error method for a negative real number using the math.erf() method −
import math
x = -0.75
result = math.erf(x)
print("Error method for x =", x, ":", result)
Output
Following is the output of the above code −
Error method for x = -0.75 : -0.7111556336535151
Example 3
In this example, we are evaluating the sum of error methods for x=2 and x/2 using the math.erf() method−
import math
x = 2
result = math.erf(x) + math.erf(x/2)
print("Error method expression result for x =", x, ":", result)
Output
We get the output as shown below −
Error method expression result for x = 2 : 1.8380230579686676
Example 4
Now, we use the math.erf() method to directly calculate the error method for x=0 −
import math
x = 0
result = math.erf(x)
print("Error method for x =", x, ":", result)
Output
The result produced is as shown below −
Error method for x = 0 : 0.0