60 lines
2.0 KiB
Mathematica
60 lines
2.0 KiB
Mathematica
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%%*******************************************************************
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%% Prod2: compute the block diagonal matrix A*B
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%%
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%% C = Prod2(blk,A,B,options);
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%%
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%% INPUT: blk = a cell array describing the block structure of A and B
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%% A,B = square matrices or column vectors.
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%%
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%% options = 0 if no special structure
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%% 1 if C is symmetric
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%%*****************************************************************
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%% SDPT3: version 4.0
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%% Copyright (c) 1997 by
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%% Kim-Chuan Toh, Michael J. Todd, Reha H. Tutuncu
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%% Last Modified: 16 Sep 2004
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%%*****************************************************************
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function C = Prod2(blk,A,B,options);
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global spdensity
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if (nargin == 3); options = 0; end;
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iscellA = iscell(A); iscellB = iscell(B);
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%%
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if (~iscellA & ~iscellB)
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if (size(blk,1) > 1);
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error('Prod2: blk and A,B are not compatible');
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end;
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if strcmp(blk{1},'s')
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numblk = length(blk{2});
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isspA = issparse(A); isspB = issparse(B);
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if (numblk > 1)
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if ~isspA; A=sparse(A); isspA=1; end
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if ~isspB; B=sparse(B); isspB=1; end
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end
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%%use_matlab = (options==0 & ~isspA & ~isspB) | (isspA & isspB);
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use_matlab = (~isspA & ~isspB) | (isspA & isspB);
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if (use_matlab)
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C = A*B;
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if (options==1); C = 0.5*(C+C'); end;
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else
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C = mexProd2(blk,A,B,options);
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end
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checksparse = (numblk==1) & (isspA | isspB);
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if (checksparse)
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n2 = sum(blk{2}.*blk{2});
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if (mexnnz(C) <= spdensity*n2);
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if ~issparse(C); C = sparse(C); end;
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else
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if issparse(C); C = full(C); end;
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end
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end
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elseif (strcmp(blk{1},'q') | strcmp(blk{1},'l') | strcmp(blk{1},'u'))
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C = A.*B;
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end
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else
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error(['Prod2: A,B must be matrices']);
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end
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%%*******************************************************************
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