Blockwise

Blockwise refers to the technique of dividing a data set or a computation into discrete, fixed-size blocks and performing operations on each block, either independently or in sequence. This approach is widely used to manage memory consumption, enable streaming I/O, improve cache efficiency, and facilitate parallel processing. In computing, blockwise processing is common when handling large files or continuous data streams, where data are read, processed, and written in blocks rather than as a single monolithic unit.

In data encoding and graphics, blockwise methods are used in transform coding and compression. For example, images and video are often divided into small blocks (e.g., 8x8 or 16x16) and subjected to discrete transforms before quantization and encoding. In linear algebra, blockwise or block matrix operations perform calculations on submatrices, which can simplify implementation and enable optimizations for structured matrices.

In networking and protocols, blockwise transfer refers to sending a large payload in smaller blocks. A notable example is CoAP’s blockwise transfer, which uses block numbers and a flag indicating more blocks to enable reliable transfer over constrained networks.

In cryptography, blockwise concepts appear with block ciphers that transform fixed-size blocks of plaintext into ciphertext, often requiring padding and specific modes to handle data that does not align with block boundaries.