Controlling the Plot range of matplotlib , use problem of 100% of ram memory

Question

Hello community of Stackoverflow :)

I am developing a small code that will plot you from 2 filled lists from an equation while a while condition is not satisfied.

Once the lists are filled in, I use matplotlib to plot the two-dimensional graph with the extracted values, but it’s a lot of values and I’d like to know if you can only plot points at specific intervals, because if I plot them all, memory usage of my PC goes up to 100% and Python crashes and gives memory error. There would be a way to optimize this process?

For example, using the range of one in a nanometer (which is the case I’m trying to solve)

# Modelando a energia do fóton em uma equação

from matplotlib import pyplot as plt

h = 1.05457168 * 10**(-34) # J * s
c = 299792458.0 #m/s
i = 0.000004 #metros
energias =[] 
wavelenghts=[]


while (i!=0.000007):
    E = (h*c)/i
    energias.append(E)
    wavelenghts.append(i)
    i=i+0.000001

print (energias)
print (wavelenghts)

plt.plot (energias, wavelenghts, color='blue', marker = 'o', linestyle = 'solid')

Answer 1

Perhaps the problem is with the accuracy of the variable. Change line 12 of

while (i!=0.000007):

for

while (i<=0.000007): # menor ou igual a 0.000007

The comment below from @Eltonnunes is perfect. Just complementing: comparisons of inequity (!=) are problematic when using floating point operations given the imprecision as the calculation involves more and more decimals as a result of the specification IEEE-754.

Another way to avoid this behavior would be to maintain its loop with an entire variable, thus preserving the expected behavior by comparing inequity:

i = 4 #metros
[...]

while (i!=7):
    vi = i/1000000
    E = (h*c)/vi
    energias.append(E)
    wavelenghts.append(vi)
    i=i+1