question: public static int computeBlockSize ( long len , long blockIndex , long blockSize ) { long remain = len - ( blockIndex - 1 ) * blockSize ; return ( int ) Math . min ( blockSize , remain ) ; }
target:  Computes the actual block size based on matrix dimension, block index, and block size meta data. For boundary blocks, the actual block size is less or equal than the block  size meta data; otherwise they are identical.  