Permanent Nan in NP

[Antigr]

need to conduct some analysis of the image, do not go into the questions what this formula is, it does not matter.

import numpy as np
from PIL import Image
#np.seterr(divide='ignore', invalid='ignore')
image=Image.open('E://test.jpg')
imgr,imgg,imgb=image.split()
r=np.asarray(imgr).astype('float64')
g=np.asarray(imgg).astype('float64')
b=np.asarray(imgb).astype('float64')
vari=(g-r)/(g+r-b)
nan=0
a=[]
for i in range (len(vari)):
    for j in range(len(vari[i])):
        if np.isnan(vari[i][j]):
            print ('NAN object',i,j)
            a=[]
            if not np.isnan(vari[i-1][j-1]):
                a.append(vari[i-1][j-1])
            if not np.isnan(vari[i-1][j]):
                a.append(vari[i-1][j])
            if not np.isnan(vari[i-1][j+1]):
                a.append(vari[i-1][j+1])#1st
            if not np.isnan(vari[i][j-1]):
                a.append(vari[i][j-1])
            if not np.isnan(vari[i][j+1]):
                a.append(vari[i][j+1])
            if not np.isnan(vari[i+1][j-1]):
                a.append(vari[i+1][j-1])
            if not np.isnan(vari[i+1][j]):
                a.append(vari[i+1][j])
            if not np.isnan(vari[i+1][j+1]):
                a.append(vari[i+1][j+1])
            a=np.asarray(a)
            print ('array',a,'mean',np.mean(a))
            vari[i][j]=0   
            nan=nan+1
print('TOTAL NAN',nan)
for i in range (len(vari)):
    for j in range(len(vari[i])):
        if np.isnan(vari[i][j]):
            print ('new NAN object',i,j)
s=0
vari=vari.ravel()
vari2=list(vari)
for i in range(len(vari2)):
    s=s+vari[i]

Code explanations: I need to calculate np.std and np.mean of full 2d array. But there is NaN alltime, i tried to delete Nan in loop, and check sum, but it is NaN too

[Larz60+]

would you please attach image (test.jpg) so that the code can be run?

[Antigr]

would you please attach image (test.jpg) so that the code can be run?

https://ibb.co/caLfkT
sorry, there was error first time, there must be image, thank you

---

would you please attach image (test.jpg) so that the code can be run?

I hope u can help me, if u got question about code u can ask me

[Larz60+]

I'll give it a go.

[Antigr]

I'll give it a go.

import numpy as np
from PIL import Image
import math
#np.seterr(divide='ignore', invalid='ignore')
image=Image.open('E:/test.jpg')
imgr,imgg,imgb=image.split()
r=np.asarray(imgr).astype('float64')
g=np.asarray(imgg).astype('float64')
b=np.asarray(imgb).astype('float64')
vari=(g-r)/(g+r-b)
nan=0
a=[]
for i in range (len(vari)):
    for j in range(len(vari[i])):
        if not np.isnan(vari[i][j]):
            b=float(vari[i][j])
            a.append(b)
        else:
            vari[i][j]=1
            nan=nan+1
print('len vari',len(vari)*len(vari[0]))
print('len a (no NaN elements)',len(a))
print('TOTAL NAN',nan)
for i in range (len(vari)):
    for j in range(len(vari[i])):
        if np.isnan(vari[i][j]):
            print ('new NAN object',i,j)
s=0
vari=vari.ravel()
for i in range (len(a)):
    if math.isnan(a[i]):
        print ('new NAN object in a massiv',i,j)
for i in range(len(a)):
    s=s+a[i]
print ('summa iz a',s)
s2=0
for i in range(len(vari)):
    s2=s2+vari[i]
print ('summa',s2)

this is new version, sum is nan

[Larz60+]

There are warnings about divide by zero errors

I modified the code a bit so as to find the image file on my computer, but nothing else:

import numpy as np
from PIL import Image
import math
import os
#np.seterr(divide='ignore', invalid='ignore')

path = os.path.dirname(__file__)
os.chdir(path)
path = os.getcwd()

image = Image.open(os.path.abspath('../images/test.jpg'))
# image=Image.open('E:/test.jpg')

imgr,imgg,imgb=image.split()
r=np.asarray(imgr).astype('float64')
g=np.asarray(imgg).astype('float64')
b=np.asarray(imgb).astype('float64')
vari=(g-r)/(g+r-b)
nan=0
a=[]
for i in range (len(vari)):
    for j in range(len(vari[i])):
        if not np.isnan(vari[i][j]):
            b=float(vari[i][j])
            a.append(b)
        else:
            vari[i][j]=1
            nan=nan+1
print('len vari',len(vari)*len(vari[0]))
print('len a (no NaN elements)',len(a))
print('TOTAL NAN',nan)
for i in range (len(vari)):
    for j in range(len(vari[i])):
        if np.isnan(vari[i][j]):
            print ('new NAN object',i,j)
s=0
vari=vari.ravel()
for i in range (len(a)):
    if math.isnan(a[i]):
        print ('new NAN object in a massiv',i,j)
for i in range(len(a)):
    s=s+a[i]
print ('summa iz a',s)
s2=0
for i in range(len(vari)):
    s2=s2+vari[i]
print ('summa',s2)

run:

Output:
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

m:/python/e-h/f/forum/g-m/ImageSoftware/src/June26-2018.py:18: RuntimeWarning: divide by zero encountered in true_divide
  vari=(g-r)/(g+r-b)
m:/python/e-h/f/forum/g-m/ImageSoftware/src/June26-2018.py:18: RuntimeWarning: invalid value encountered in true_divide
  vari=(g-r)/(g+r-b)
len vari 2666000
len a (no NaN elements) 2665987
TOTAL NAN 13
summa iz a nan
m:/python/e-h/f/forum/g-m/ImageSoftware/src/June26-2018.py:46: RuntimeWarning: invalid value encountered in double_scalars
  s2=s2+vari[i]
summa nan

[Antigr]

There are warnings about divide by zero errors I modified the code a bit so as to find the image file on my computer, but nothing else:

 import numpy as np from PIL import Image import math import os #np.seterr(divide='ignore', invalid='ignore') path = os.path.dirname(__file__) os.chdir(path) path = os.getcwd() image = Image.open(os.path.abspath('../images/test.jpg')) # image=Image.open('E:/test.jpg') imgr,imgg,imgb=image.split() r=np.asarray(imgr).astype('float64') g=np.asarray(imgg).astype('float64') b=np.asarray(imgb).astype('float64') vari=(g-r)/(g+r-b) nan=0 a=[] for i in range (len(vari)): for j in range(len(vari[i])): if not np.isnan(vari[i][j]): b=float(vari[i][j]) a.append(b) else: vari[i][j]=1 nan=nan+1 print('len vari',len(vari)*len(vari[0])) print('len a (no NaN elements)',len(a)) print('TOTAL NAN',nan) for i in range (len(vari)): for j in range(len(vari[i])): if np.isnan(vari[i][j]): print ('new NAN object',i,j) s=0 vari=vari.ravel() for i in range (len(a)): if math.isnan(a[i]): print ('new NAN object in a massiv',i,j) for i in range(len(a)): s=s+a[i] print ('summa iz a',s) s2=0 for i in range(len(vari)): s2=s2+vari[i] print ('summa',s2) 

run:

Output:
 Microsoft Windows [Version 6.1.7601] Copyright (c) 2009 Microsoft Corporation. All rights reserved. m:/python/e-h/f/forum/g-m/ImageSoftware/src/June26-2018.py:18: RuntimeWarning: divide by zero encountered in true_divide vari=(g-r)/(g+r-b) m:/python/e-h/f/forum/g-m/ImageSoftware/src/June26-2018.py:18: RuntimeWarning: invalid value encountered in true_divide vari=(g-r)/(g+r-b) len vari 2666000 len a (no NaN elements) 2665987 TOTAL NAN 13 summa iz a nan m:/python/e-h/f/forum/g-m/ImageSoftware/src/June26-2018.py:46: RuntimeWarning: invalid value encountered in double_scalars s2=s2+vari[i] summa nan 

yes i know about it, but in a array there is no NaN elements, and sum is 0

[volcano63]

You are abusing both numpy and Python

vari[~np.isnan(vari)].tolist()

will give you the list of non-NaN values in your array.

Iteration over indices is extremely un-Pythonic

[Antigr]

Thank you all!