Alibaba Group Holding Limited
SPARSE MATRIX CALCULATIONS UNTILIZING IGHTLY COUPLED MEMORY AND GATHER/SCATTER ENGINE

Abstract:

A processor for sparse matrix calculation can include an on-chip memory, a cache, a gather/scatter engine and a core. The on-chip memory can be configured to store a first matrix or vector, and the cache can be configured to store a compressed sparse second matrix data structure. The compressed sparse second matrix data structure can include: a value array including non-zero element values of the sparse second matrix, where each entry includes a given number of element values; and a column index array where each entry includes the given number of offsets matching the value array. The gather/scatter engine can be configured to gather element values of the first matrix or vector using the column index array of the sparse second matrix. In a horizontal implementation, the gather/scatter engine can be configured to gather sets of element values from different sub-banks within a same row based on the column index array of the sparse matrix. In a vertical implementation, the gather/scatter engine can be configured to gather sets of element values from different rows based on the column index array of the sparse matrix. In a hybrid horizontal/vertical implementation, the gather/scatter engine can be configured to gather sets of element values from sets of rows and from different sub-banks within the same rows based on the column index array of the sparse matrix. The core can be configured to perform sparse matrix-matrix multiplication or sparse-matrix-vector multiplication using the gathered elements of the first matrix or vector and the value array of the compressed sparse second matrix.