laspy使用多进程将文件分成多个块读取代码示例

以下是使用laspy库将文件分成多个块读取的代码示例：

import laspy
import multiprocessing

def read_las_chunk(filename, start_idx, end_idx):
    with laspy.file.File(filename, mode='r') as f:
        points = f.points[start_idx:end_idx]
    return points

if __name__ == '__main__':
    filename = 'filename.las'

    # get total number of points
    with laspy.file.File(filename, mode='r') as f:
        n_points = f.header.point_count

    chunk_size = 100000  # number of points to read in each chunk
    n_processes = multiprocessing.cpu_count()

    # split the file into chunks
    chunks = [(i * chunk_size, min((i + 1) * chunk_size, n_points)) for i in range((n_points - 1) // chunk_size + 1)]

    pool = multiprocessing.Pool(n_processes)

    # read each chunk in parallel
    results = [pool.apply_async(read_las_chunk, args=(filename, start_idx, end_idx)) for (start_idx, end_idx) in chunks]

    # combine results into a single array
    points = []
    for result in results:
        points.extend(result.get())

这段代码使用了multiprocessing库，将文件切分成多个块，然后在不同的进程中并行读取每个块。最后，它将所有的点合并到一个单独的列表中。