from builtins import range
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from past.builtins import xrange
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from math import sqrt, ceil
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import numpy as np
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def visualize_grid(Xs, ubound=255.0, padding=1):
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"""
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Reshape a 4D tensor of image data to a grid for easy visualization.
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Inputs:
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- Xs: Data of shape (N, H, W, C)
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- ubound: Output grid will have values scaled to the range [0, ubound]
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- padding: The number of blank pixels between elements of the grid
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"""
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(N, H, W, C) = Xs.shape
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grid_size = int(ceil(sqrt(N)))
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grid_height = H * grid_size + padding * (grid_size - 1)
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grid_width = W * grid_size + padding * (grid_size - 1)
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grid = np.zeros((grid_height, grid_width, C))
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next_idx = 0
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y0, y1 = 0, H
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for y in range(grid_size):
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x0, x1 = 0, W
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for x in range(grid_size):
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if next_idx < N:
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img = Xs[next_idx]
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low, high = np.min(img), np.max(img)
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grid[y0:y1, x0:x1] = ubound * (img - low) / (high - low)
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# grid[y0:y1, x0:x1] = Xs[next_idx]
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next_idx += 1
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x0 += W + padding
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x1 += W + padding
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y0 += H + padding
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y1 += H + padding
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# grid_max = np.max(grid)
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# grid_min = np.min(grid)
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# grid = ubound * (grid - grid_min) / (grid_max - grid_min)
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return grid
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def vis_grid(Xs):
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""" visualize a grid of images """
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(N, H, W, C) = Xs.shape
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A = int(ceil(sqrt(N)))
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G = np.ones((A*H+A, A*W+A, C), Xs.dtype)
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G *= np.min(Xs)
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n = 0
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for y in range(A):
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for x in range(A):
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if n < N:
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G[y*H+y:(y+1)*H+y, x*W+x:(x+1)*W+x, :] = Xs[n,:,:,:]
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n += 1
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# normalize to [0,1]
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maxg = G.max()
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ming = G.min()
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G = (G - ming)/(maxg-ming)
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return G
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def vis_nn(rows):
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""" visualize array of arrays of images """
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N = len(rows)
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D = len(rows[0])
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H,W,C = rows[0][0].shape
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Xs = rows[0][0]
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G = np.ones((N*H+N, D*W+D, C), Xs.dtype)
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for y in range(N):
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for x in range(D):
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G[y*H+y:(y+1)*H+y, x*W+x:(x+1)*W+x, :] = rows[y][x]
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# normalize to [0,1]
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maxg = G.max()
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ming = G.min()
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G = (G - ming)/(maxg-ming)
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return G
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