ValueError:无效的RGBA参数：此错误的原因是什么？

Question

我正在尝试创建一个二维彩色条形图

import numpy as np
import matplotlib.pyplot as plt
import pickle
from graphviz import Digraph
from torch.autograd import Variable
import argparse


def make_dot(var):
    '''
    Visualization of the computation graph
    Taken from : https://github.com/szagoruyko/functional-zoo/blob/master/visualize.py
    '''
    node_attr = dict(style='filled',
                     shape='box',
                     align='left',
                     fontsize='12',
                     ranksep='0.1',
                     height='0.2')
    dot = Digraph(node_attr=node_attr, graph_attr=dict(size="12,12"))
    seen = set()

    def add_nodes(var):
        if var not in seen:
            if isinstance(var, Variable):
                value = '('+(', ').join(['%d' % v for v in var.size()])+')'
                dot.node(str(id(var)), str(value), fillcolor='lightblue')
            else:
                dot.node(str(id(var)), str(type(var).__name__))
            seen.add(var)
            if hasattr(var, 'previous_functions'):
                for u in var.previous_functions:
                    dot.edge(str(id(u[0])), str(id(var)))
                    add_nodes(u[0])
    add_nodes(var.creator)
    return dot


def plot_trajectories(true_trajs, pred_trajs, nodesPresent, obs_length, name, plot_directory, withBackground=False):
    '''
    Parameters
    ==========

    true_trajs : Numpy matrix of shape seq_length x numNodes x 2
    Contains the true trajectories of the nodes

    pred_trajs : Numpy matrix of shape seq_length x numNodes x 2
    Contains the predicted trajectories of the nodes

    nodesPresent : A list of lists, of size seq_length
    Each list contains the nodeIDs present at that time-step

    obs_length : Length of observed trajectory

    name : Name of the plot

    withBackground : Include background or not
    '''

    traj_length, numNodes, _ = true_trajs.shape
    # Initialize figure
    plt.figure()

    # Load the background
    # im = plt.imread('plot/background.png')
    # if withBackground:
    #    implot = plt.imshow(im)

    # width_true = im.shape[0]
    # height_true = im.shape[1]

    # if withBackground:
    #    width = width_true
    #    height = height_true
    # else:
    width = 1
    height = 1

    traj_data = {}
    for tstep in range(traj_length):
        pred_pos = pred_trajs[tstep, :]
        true_pos = true_trajs[tstep, :]

        for ped in range(numNodes):
            if ped not in traj_data and tstep < obs_length:
                traj_data[ped] = [[], []]

            if ped in nodesPresent[tstep]:
                traj_data[ped][0].append(true_pos[ped, :])
                traj_data[ped][1].append(pred_pos[ped, :])

    for j in traj_data:
        c = np.random.rand(3, 1)
        true_traj_ped = traj_data[j][0]  # List of [x,y] elements
        pred_traj_ped = traj_data[j][1]

        true_x = [(p[0]+1)/2*height for p in true_traj_ped]
        true_y = [(p[1]+1)/2*width for p in true_traj_ped]
        pred_x = [(p[0]+1)/2*height for p in pred_traj_ped]
        pred_y = [(p[1]+1)/2*width for p in pred_traj_ped]

        plt.plot(true_x, true_y, color=c, linestyle='solid', marker='o')
        plt.plot(pred_x, pred_y, color=c, linestyle='dashed', marker='x')

    if not withBackground:
        plt.ylim((1, 0))
        plt.xlim((0, 1))

    # plt.show()
    if withBackground:
        plt.savefig('plot_with_background/'+name+'.png')
    else:
        plt.savefig(plot_directory+'/'+name+'.png')

    plt.gcf().clear()
    plt.close()


def main():
    parser = argparse.ArgumentParser()

    # Experiments

    parser.add_argument('--test_dataset', type=int, default=0,
                        help='test dataset index')

    # Parse the parameters
    args = parser.parse_args()

    # Save directory
    save_directory = 'save/'
    save_directory += str(args.test_dataset) + '/'
    plot_directory = 'plot/'

    f = open(save_directory+'/results.pkl', 'rb')
    results = pickle.load(f)

    # print "Enter 0 (or) 1 for without/with background"
    # withBackground = int(input())
    withBackground = 1

    for i in range(len(results)):
        print i
        name = 'sequence' + str(i)
        plot_trajectories(results[i][0], results[i][1], results[i][2], results[i][3], name, plot_directory, withBackground)


if __name__ == '__main__':
    main()

现在我无法调试Invalid RGBA argument，因为我不明白是什么导致了错误。我甚至尝试使用随机颜色来代替colors = np.random.rand(91,91,4)，但错误仍然存在

我已经检查了关于无效RGBA参数的堆栈溢出帖子（例如，this，this和this），它们似乎都没有回答我的问题

我想知道是什么导致了这个错误。我在Ubuntu Mate 16上使用Python的标准Anaconda发行版

是否由于Python最近的更新，原始堆栈溢出帖子中的解决方案变得过时了

Answer 1

替换

c = np.random.rand(3, 1)

为此：

c = np.random.rand(3)

它消除了错误matplotlib要求c参数为（3，）或（4，）形状