We Keep Coding

Numpy and Matplotlib Error with very Minimal Example

I have been using numpy and matplotlib together for some time now, successfully. Suddenly, I am getting unusual errors when using them together. The following is a minimal example:
import numpy as np
import matplotlib.pyplot as plt
fig,ax = plt.subplots(1,1)
x = np.eye(10)
u = np.linalg.svd(x)
plt.show()
If I run the code once, it works. If I run the code again, I get an exception:
LinAlgError: SVD did not converge. Bizarrely, this behavior disappears when the call to pyplot is removed:
import numpy as np
import matplotlib.pyplot as plt
#fig,ax = plt.subplots(1,1)
x = np.eye(10)
u = np.linalg.svd(x)
#plt.show()
I tried this with two different python environments with numpy versions 18.1 and 18.5. I am wondering if anyone has any information about what could possibly cause this behavior.
edit: I was running these two blocks of code in a jupyter notebook with only those lines of code and nothing else. In order to reproduce the behavior in the interactive interpreter, you need to add the line plt.show() in between runs. I edited the post to include this line.
edit: matplotlib 3.3.2, numpy 18.1 or 18.5, and I can use python 3.8.1 or 3.6.8

'function' object has no attribute 'fft2' error scipy

I am struggling with an error called 'function' object has no attribute 'fft2'. First of all,
I have imported the following:
import cv2
import matplotlib.pyplot as plt
import numpy as np
from scipy import fft
After executing the following block of code in jupyter notebook:
gainDisplay=1
InImgFFT=fft.fft2(InImg,norm="ortho")
InImgAmplSpec=np.abs(fft.fftshift(InImgFFT))
plt.figure(figsize=(W/DPI+1,H/DPI+1))
plt.imshow(np.clip(InImgAmplSpec*gainDisplay,0,255),cmap = 'rainbow')
plt.suptitle('The amplitude spectrum of the gray scale input image')
plt.show()
I get the error mentioned at the line with fft.fft2() function
Could you please help me to solve this error?
scipy version is 1.5.2
Another mention would be that I have a conda environment where i have installed all the packets, but I hope that won't be a problem.

Python not showing plots

When I run the following code, plots don't show up even though I am not getting any error messages.
import matplotlib.pyplot as plt
plt.plot = ([1,2], [1,2])
plt.show()
I tried the following
1) Change Spyder->Preferences->Graphics backend = Automatic (Reset kernel)
2)
import matplotlib
matplotlib.use('Agg')
Got error: "no effect because the backend has already been chosen"
I am using Python 3.6 with Spyder that comes with Anaconda

there is an error in your code, it must be:
import matplotlib.pyplot as plt
plt.plot([1,2], [1,2])
plt.show()

Python codes using numpy and matplotlib without outputting result

I just started learning doing financial analytics with python today. I ran into a block of code and it requires importing numpy and matplotlib to run the codes and generate a graph(not sure if it really can).
The codes are like this:
import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt
mpl.rcParams['font.family'] = 'serif'
K = 8000
S = np.linspace(7000,9000,100)
h = np.maximum(S-K, 0)
plt.figure()
plt.plot(S, h, lw=2.5)
plt.xlabel('index level $S-t$ at maturity')
plt.ylabel("inner value of European call option")
plt.grid(True)
I installed both numpy and matplotlib but after I tried running the codes nothing came out.
I really don't know what went wrong. This is my first time using numpy and matplotlib and I have not idea how to solve this problem.
Please help!

backend_qt5.py "'figure' is an unknown keyword argument, In matplotlib

I am trying to run a simple code to plot my data using matplotlib in python2.7.10 :
import matplotlib.pyplot as plt
y=[23,35,43,54,76]
x=[2,4,5,6,7]
plt.plot(y,x)
I am getting the error:
super(FigureCanvasQTAggBase, self).__init__(figure=figure)
File "/usr/local/lib/python2.7/dist-packages/matplotlib/backends/backend_qt5.py", line 239, in __init__
super(FigureCanvasQT, self).__init__(figure=figure)
TypeError: 'figure' is an unknown keyword argument
How can I fix it?

This seems to be a duplicate of: matplotlib Qt5Agg backend error: 'figure' is an unknown keyword argument, which I just posted an answer for, and duplicated below:
I had the same issue. I found the solution here
Specifically, the following now works:
import matplotlib
matplotlib.use('Qt4Agg')
from matplotlib import pyplot as plt
plt.figure(figsize=(12,8))
plt.title("Score")
plt.show()

Just adding to Marc's answer. If you are using Spyder,
matplotlib.use('Qt4Agg')
may not work well because matplotlib has been imported when you open Spyder.
Instead you can go to (in Spyder) Tools - Preferences -IPython console - Graphics to change the backend and restart Spyder.

adding to this, i ran into this problem when i wanted to plot my values for my KNN training sets and test set results.
using TkAgg also fixes the problem
"matplotlib.use('TkAgg')"
import matplotlib
matplotlib.use('TkAgg')
#matplotlib.use('Qt4Agg')
import matplotlib.pyplot as plt
plt.figure(figsize=(12,8))
plt.title("Score")
plt.show()