英文:
ValueError: x and y must have same first dimension, but have shapes (5,) and (1,)
问题
import timeimport randomimport matplotlib.pyplot as pltdef brute_force(values, weights, capacity):num_items = len(values)max_value = 0subset = []for i in range(2**num_items):current_value = 0current_weight = 0current_subset = []for j in range(num_items):if(i & (1 << j)) != 0:current_value += values[j]current_weight += weights[j]current_subset.append(j)if current_weight <= capacity and current_value > max_value:max_value = current_valuesubset = current_subsetreturn max_value, subsetinput_sizes = [10, 20, 30, 40, 50]running_times = []for size in input_sizes:values = [random.randint(1, 100) for _ in range(size)]weights = [random.randint(1, 100) for _ in range(size)]capacity = sum(weights) // 2start_time = time.time()max_value, subset = brute_force(values, weights, capacity)end_time = time.time()running_time = end_time - start_timerunning_times.append(running_time)print(f"Input size: {size}")print(f"Chosen subset: {subset}")print(f"Chosen weight: {sum(weights[i] for i in subset)}")print(f"Running time: {running_time:.6f} seconds")plt.plot(input_sizes, running_times, marker='o')plt.xlabel('Input size')plt.ylabel('Running time (s)')plt.title('Brute force Knapsack')plt.show()
英文:
I'm creating a brute force approach for the knapsack problem, unfortunately when trying to graph the results I get this error: ValueError: x and y must have same first dimension, but have shapes (5,) and (1,)
import timeimport randomimport matplotlib.pyplot as pltdef brute_force(values, weights, capacity):num_items = len(values)max_value = 0subset = []for i in range(2**num_items):current_value = 0current_weight = 0current_subset = []for j in range(num_items):if(i & (1 << j)) != 0:current_value += values[j]current_weight += weights[j]current_subset.append(j)if current_weight <= capacity and current_value > max_value:max_value = current_valuesubset = current_subsetreturn max_value, subsetinput_sizes = [10, 20, 30, 40, 50]running_times = []for size in input_sizes:values = [random.randint(1,100) for _ in range(size)]weights = [random.randint(1, 100) for _ in range(size)]capacity = sum(weights) // 2start_time = time.time()max_value, subset = brute_force(values, weights, capacity)end_time = time.time()running_time = end_time - start_timerunning_times.append(running_time)print(f"Input size: {size}")print(f"Chosen subset: {subset}")print(f"Chosen weight: {sum(weights[i] for i in subset)}")print(f"Running time: {running_time: .6f} seconds")plt.plot(input_sizes, running_times, marker = 'o')plt.xlabel('Input size')plt.ylabel('Running time (s)')plt.title('Brute force Knapsack')plt.show()
答案1
得分: 0
# 在循环内部有 `plt`，这意味着 `running_times` 只有一个值，而 `input_sizes` 有 5 个值...这样应该可以工作：```pythonimport timeimport randomimport matplotlib.pyplot as pltdef brute_force(values, weights, capacity):num_items = len(values)max_value = 0subset = []for i in range(2**num_items):current_value = 0current_weight = 0current_subset = []for j in range(num_items):if(i & (1 << j)) != 0:current_value += values[j]current_weight += weights[j]current_subset.append(j)if current_weight <= capacity and current_value > max_value:max_value = current_valuesubset = current_subsetreturn max_value, subsetinput_sizes = [10, 20, 30, 40, 50]running_times = []for size in input_sizes:values = [random.randint(1,100) for _ in range(size)]weights = [random.randint(1, 100) for _ in range(size)]capacity = sum(weights) // 2start_time = time.time()max_value, subset = brute_force(values, weights, capacity)end_time = time.time()running_time = end_time - start_timerunning_times.append(running_time)print(f"Input size: {size}")print(f"Chosen subset: {subset}")print(f"Chosen weight: {sum(weights[i] for i in subset)}")print(f"Running time: {running_time: .6f} seconds")plt.plot(input_sizes, running_times, marker = 'o')plt.xlabel('Input size')plt.ylabel('Running time (s)')plt.title('Brute force Knapsack')plt.show()
我将 input_list 减小为 [1, 2, 3, 4, 5]（为了速度，你可以将其改回），输出如下：
<details><summary>英文:</summary>The `plt` was inside the loop meaning that `running_times` has only one value whereas `input_sizes` has 5 values...This should work:```pythonimport timeimport randomimport matplotlib.pyplot as pltdef brute_force(values, weights, capacity):num_items = len(values)max_value = 0subset = []for i in range(2**num_items):current_value = 0current_weight = 0current_subset = []for j in range(num_items):if(i & (1 << j)) != 0:current_value += values[j]current_weight += weights[j]current_subset.append(j)if current_weight <= capacity and current_value > max_value:max_value = current_valuesubset = current_subsetreturn max_value, subsetinput_sizes = [10, 20, 30, 40, 50]running_times = []for size in input_sizes:values = [random.randint(1,100) for _ in range(size)]weights = [random.randint(1, 100) for _ in range(size)]capacity = sum(weights) // 2start_time = time.time()max_value, subset = brute_force(values, weights, capacity)end_time = time.time()running_time = end_time - start_timerunning_times.append(running_time)print(f"Input size: {size}")print(f"Chosen subset: {subset}")print(f"Chosen weight: {sum(weights[i] for i in subset)}")print(f"Running time: {running_time: .6f} seconds")plt.plot(input_sizes, running_times, marker = 'o')plt.xlabel('Input size')plt.ylabel('Running time (s)')plt.title('Brute force Knapsack')plt.show()
i reduced the input_list to [1, 2, 3, 4, 5] (for speed, so you can put it back) and the output looks like this:
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