A SYSTOLIC BLOCK-JACOBI SVD SOLVER FOR PROCESSOR MESHES
A SYSTOLIC BLOCK-JACOBI SVD SOLVER FOR PROCESSOR MESHES
复制标题
处理器网格的脉动块雅可比 SVD 求解器
DOI:
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发表时间:
2003
期刊:
影响因子:
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通讯作者:
VAJTERSˇIC
中科院分区:
文献类型:
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作者:
Gabriel OKSˇA;MARIA´N;VAJTERSˇIC
Wedesignthesystolicversionofthetwo-sidedblock-Jacobialgorithmforthesingularvalue decomposition(SVD)of matrix A [ R m £ n , m $ n and m , n even. The algorithm involves the class CO of parallel orderings on the two-dimensionaltoroidalmeshwith p processors.ThemathematicalbackgroundisbasedontheQRdecomposition(QRD) of local data matrices and on the triangular Kogbetliantz algorithm (TKA) for local SVDs in the diagonal mesh processors. Subsequentupdatesoflocalmatrices inthediagonalas wellasnondiagonalmeshprocessorsare required. We show that all updates can be realized by orthogonal modified Givens rotations. These rotations can be efficiently pipelined in parallel in the horizontal and vertical rings of ffiffiffi p p processor through the toroidal mesh. Our solution requires, per one mesh processor, O ½ð m þ n Þ 2 = p (cid:6) systolic processing elements (PEs) and additional delay elements. The time complexity can be estimated as T p < O ½ð m þ ð n 3 = 2 = p 1 = 4 ÞÞ w D (cid:6) where w is the number of global sweeps in the two-sided block-Jacobi algorithm and D is the length of the global synchronization time step. The VLSI area per meshprocessor,measuredbythenumberofverticalandhorizontalwiresrequiredforitsconstruction,canbeestimatedas A < O ½ð m þ n Þ 2 = p (cid:6) ; and the combined VLSI area–time complexity per mesh processor is AT 2 < O ½ðð m þ n Þ 2 m 2 n 3 = p 5 = 4 Þ w 2 D 2 (cid:6) : The theoretical speedup can be estimated as S p < O ð p 1 = 4 m 2 n = ð p 1 = 4 m þ n 3 = 2 ÞÞ : Using the mesh processorsoffixedinnersize ^ m £ ^ n ; ^ m , ^ n even,itispossibletoconstructthesquaretwo-dimensionaltoroidalmeshand to compute the SVD of matrix A , the size of the which matches the shape of mesh processors, i.e. m = n ¼ ^ m = ^ n : In this sense, the systolic algorithm is scalable.