Question

why doesnt this work it isnt checking nans propperly

import numpy as np
import time
x = np.linspace(-2,-1,100)
y = np.linspace(-1.5,1.5,100)
z0 = 0
z1s = []
for i in x:
for k in y:
z1 = (z0)**2 + i + k*1j
z0 = z1
if np.real(z0) == np.nan:########## this doesnt work. it never detects nans
print('nan') ### this NEVER prints. it should print after about 10 seconds
pass
if np.real(z0) != np.nan:
print('not nan')
z1s.append(z1)
print(z1)
time.sleep(1)
print(z1s)
################################## how do i get it to check for nans propperly. also how do i stop the runtime error

Answer 1

Please find the answer below::

Here np.isnan should be used to check if number is NaN.

Code is as below:

import numpy as np
import time
x = np.linspace(-2,-1,10)
y = np.linspace(-1.5,1.5,10)
z0 = 0
z1s = []
for i in x:
for k in y:
z1 = (z0)**2 + i + k*1j
z0 = z1
if np.isnan(np.real(z0)):########## this doesnt work. it never detects nans
print('nan') ### this NEVER prints. it should print after about 10 seconds
else:
print('not nan')
z1s.append(z1)
print(z1)
time.sleep(1)
print(z1s)

output:

Also run time error is coming due to overflow value assigned to data type. This can be resolved only by changing logic to code or by using appropriate data type.