starts = range0 shape0 chunk_sizeends = starts1 + shape0

These two lines of code are used to create a list of start and end indices for dividing a dataset into smaller chunks of a specified size.

The first line creates a range object starting from 0 and ending at the size of the dataset (shape[0]), with a step size of chunk_size. For example, if the dataset has 100 elements and chunk_size is 10, the range object will contain the values [0, 10, 20, 30, 40, 50, 60, 70, 80, 90].

The second line creates a list of end indices by taking the start indices from the first line and shifting them by one position to the right, and appending the last index of the dataset to the end of the list. For the example above, the list of end indices would be [10, 20, 30, 40, 50, 60, 70, 80, 90, 100].

Together, these two lines create a list of pairs of start and end indices that define non-overlapping chunks of the dataset of size chunk_size. For example, the first chunk would be the elements from index 0 to index 9, the second chunk would be the elements from index 10 to index 19, and so on.