Fix ValueError: setting an array element with a sequence

[pira998]

Fix #60 The cause of this error is that the all_vals_res lists contain nested lists or arrays with different shapes. The np.split function only works with 1-D arrays and will raise an error if it encounters a nested list or array with a different shape.

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[bottler]

I think this fix in pytorch3d/implicitron could be made here as well, and that would fix this problem, perhaps more efficiently.

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[pira998]

Yes @bottler. I agree that the fix in pytorch3d/implicitron could be a good solution for this problem. Because the iter() function creates an iterator for the array and the zip() function combines the elements of two arrays. It then uses a list comprehension to create a new list of elements, where each element is a tuple containing the corresponding elements of the two arrays. This solution is more efficient in terms of memory usage, as it only creates a single list of tuples.

My solution uses a for loop to iterate through the indices and creates slices of the array using the slice notation. It appends each slice to a new list, which is stored in the vals variable. This solution is more efficient in terms of time complexity, as it does not need to create a new list for every iteration.

vals = []
start = 0
for idx in indices:
     vals.append(all_vals_res[start:idx])
     start = idx

In terms of which solution is better, it depends on the specific use case and the size of the input array. The first solution is more memory efficient, but the second one is more time efficient. If the size of the input array is large, the second solution is more appropriate. If memory usage is a concern, the first solution is more appropriate. In our case, memory usage is much more important. So I would go with the first solution(yours). thanks.