ValueError: x and y must have same first dimension, but have shapes (16,) and (20,)

vision
1

I already gone through stack overflow answer but i didn’t find any suitable answer. I am simply draw a PSNR graph between two excel values. The code is mentioned below

import os

import numpy as np
from scipy.misc import imread
import matplotlib.pyplot as plt

line = True

lstm_ssim = np.genfromtxt('test/psnr/bpg_psnr.csv', delimiter=',')
lstm_ssim = lstm_ssim[:, :-1]
if line:
    lstm_ssim = np.mean(lstm_ssim, axis=0)
    lstm_bpp = np.arange(1, 17) / 192 * 24
    plt.plot(lstm_bpp, lstm_ssim, label='LSTM', marker='o')
else:
    lstm_bpp = np.stack([np.arange(1, 17) for _ in range(24)]) / 192 * 24
    plt.scatter(
        lstm_bpp.reshape(-1), lstm_ssim.reshape(-1), label='LSTM', marker='o')

jpeg_ssim = np.genfromtxt('test/psnr/jpeg_psnr.csv', delimiter=',')
jpeg_ssim = jpeg_ssim[:, :-1]
if line:
    jpeg_ssim = np.mean(jpeg_ssim, axis=0)

jpeg_bpp = np.array([
    os.path.getsize('test/jpeg/kodim{:02d}/{:02d}.jpg'.format(i, q)) * 8 /
    (imread('test/jpeg/kodim{:02d}/{:02d}.jpg'.format(i, q)).size // 3)
    for i in range(1, 25) for q in range(1, 21)
]).reshape(24, 20)

if line:
    jpeg_bpp = np.mean(jpeg_bpp, axis=0)
    plt.plot(jpeg_bpp, jpeg_ssim, label='JPEG', marker='x')
else:
    plt.scatter(
        jpeg_bpp.reshape(-1), jpeg_ssim.reshape(-1), label='JPEG', marker='x')

plt.xlim(0., 2.)
plt.ylim(0.7, 1.0)
plt.xlabel('bit per pixel')
plt.ylabel('PSNR')
plt.legend()
plt.show()

There are 20 columns and 24 rows are present in excel.

Python error

Traceback (most recent call last):
  File "test/psnr/draw_psnr.py", line 14, in <module>
    plt.plot(lstm_bpp, lstm_ssim, label='LSTM', marker='o')
  File "/home/khawar/anaconda3/envs/RNN_Fresh/lib/python3.5/site-packages/matplotlib/pyplot.py", line 2749, in plot
    *args, scalex=scalex, scaley=scaley, data=data, **kwargs)
  File "/home/khawar/anaconda3/envs/RNN_Fresh/lib/python3.5/site-packages/matplotlib/__init__.py", line 1785, in inner
    return func(ax, *args, **kwargs)
  File "/home/khawar/anaconda3/envs/RNN_Fresh/lib/python3.5/site-packages/matplotlib/axes/_axes.py", line 1604, in plot
    for line in self._get_lines(*args, **kwargs):
  File "/home/khawar/anaconda3/envs/RNN_Fresh/lib/python3.5/site-packages/matplotlib/axes/_base.py", line 393, in _grab_next_args
    yield from self._plot_args(this, kwargs)
  File "/home/khawar/anaconda3/envs/RNN_Fresh/lib/python3.5/site-packages/matplotlib/axes/_base.py", line 370, in _plot_args
    x, y = self._xy_from_xy(x, y)
  File "/home/khawar/anaconda3/envs/RNN_Fresh/lib/python3.5/site-packages/matplotlib/axes/_base.py", line 231, in _xy_from_xy
    "have shapes {} and {}".format(x.shape, y.shape))
ValueError: x and y must have same first dimension, but have shapes (16,) and (20,)
(RNN_Fresh) khawar@khawar-B365-HD3:~/Desktop/RNN_Fresh/pytorch-image-comp-rnn$
2

Can you print the shapes you feed to Matplotlib and see what they are?

3

lstm_ssim.shape: The shape is (24, 21)
print(lstm_bpp.shape)
(16,)

4

I mean, the shapes of variables (lstm_bpp, lstm_ssim) you pass to Matplotlib

5

lstm_ssim.shape: The shape is (24, 21)
print(lstm_bpp.shape)
(16,)

6

Can you try to isolate which segment is giving the error (as you use plot and scatter plots) and for that, can you reshape the values you pass to Matplotlib?

Eg:
import numpy as np
import matplotlib.pyplot as plt

x = np.random.rand(24,20)
x = x[:, :-1]
print(x.shape)
x = x.mean(axis=0)

y = np.arange(1, 17) / 192 * 24
#plt.plot(x,y) #x and y must have same first dimension, but have shapes (19,) and (16,)
y = np.arange(1, 20) / 192 * 24
plt.plot(x,y) #This works