Description of readsdpa

0001 function sdpdata=readsdpa(filename); 
0002 % read the file & separate the linear constraint matrix, return
0003 % the problem in the following structure:
0004 %
0005 %function [mDIM,nBLOCK,bLOCKsTRUCT,c,F]=readsdpa(filename);
0006 %
0007 % Read a problem in SDPA sparse format.
0008 %
0009 % [mDIM,nBLOCK,bLOCKsTRUCT,c,F] = read_data(fname)
0010 %
0011 % <INPUT>
0012 % - filename: string; filename of the SDP data with SDPA foramt.
0013 %
0014 % <OUTPUT>
0015 % - mDIM       : integer; number of primal variables
0016 % - nBLOCK     : integer; number of blocks of F
0017 % - bLOCKsTRUCT: vector; represetns the block structure of F
0018 % - c          : vector; coefficient vector
0019 % - F          : cell array; coefficient matrices
0020 %
0021 
0022 % This file is a component of SDPA
0023 % edited by JF 2011
0024 %
0025 % Copyright (C) 2004 SDPA Project
0026 %
0027 % This program is free software; you can redistribute it and/or modify
0028 % it under the terms of the GNU General Public License as published by
0029 % the Free Software Foundation; either version 2 of the License, or
0030 % (at your option) any later version.
0031 %
0032 % This program is distributed in the hope that it will be useful,
0033 % but WITHOUT ANY WARRANTY; without even the implied warranty of
0034 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0035 % GNU General Public License for more details.
0036 %
0037 % You should have received a copy of the GNU General Public License
0038 % along with this program; if not, write to the Free Software
0039 % Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
0040 %
0041 % SDPA-M: $Revision: 6.2 $
0042 % $Id: read_data.m,v 6.2 2005/05/28 02:36:40 drophead Exp $
0043 
0044 % check the validity of the arguments
0045 if ( nargin ~= 1 | ( nargin == 1 & ~isstr(filename) ) )
0046   error('input argument must be a filename');
0047 end
0048 
0049 sdpdata=[];
0050 
0051 % identify whether a file is sparse format or not.
0052 bsparse=0;
0053 len=length(filename);
0054 if len >= 2
0055   str=filename(end-1:end);
0056   if strncmp(str,'-s',2) 
0057     bsparse=1;
0058   end
0059 end
0060 
0061 fid=fopen(filename,'r');
0062 if fid == -1
0063   error(sprintf('Cannot open %s',filename));
0064 end
0065 
0066 % skip comment and after it, read a number of decision variables (mDIM)
0067 while 1
0068   str=fgetl(fid);
0069   if( str(1)~='*' & str(1) ~='"' )
0070     mDIM=sscanf(str,'%d',1);
0071     break;
0072   end
0073 end
0074 %disp(sprintf('mDIM=%d',mDIM));
0075 
0076 % read a number of blocks (nBLOCK)
0077 nBLOCK=fscanf(fid,'%d',1);
0078 %disp(sprintf('nBLOCK=%d',nBLOCK));
0079 
0080 % read each size of blocks (bLOCKsTRUCT)
0081 bLOCKsTRUCT=zeros(nBLOCK,1);
0082 for idx=1:nBLOCK
0083   bLOCKsTRUCT(idx)=fscanf(fid,'%*[^0-9+-]%d',1);
0084   %if bLOCKsTRUCT(idx) == 1
0085   %  bLOCKsTRUCT(idx) = -1;
0086   %end
0087 end
0088 
0089 % read cost vector (c)
0090 c=zeros(mDIM,1);
0091 for idx=1:mDIM
0092   c(idx)=fscanf(fid,'%*[^0-9+-]%lg',1);
0093 end
0094 
0095 % read coefficient matrices (F)
0096 F=cell(nBLOCK,mDIM+1);
0097 
0098 if bsparse
0099   % sparse format case
0100   while 1
0101     [k,cnt]=fscanf(fid,'%*[^0-9+-]%d',1);
0102     [l,cnt]=fscanf(fid,'%*[^0-9+-]%d',1);
0103     [i,cnt]=fscanf(fid,'%*[^0-9+-]%d',1);
0104     [j,cnt]=fscanf(fid,'%*[^0-9+-]%d',1);
0105     [value,cnt]=fscanf(fid,'%*[^0-9+-]%lg',1);
0106     if cnt
0107       if isempty(F{l,k+1})
0108         bsize=abs(bLOCKsTRUCT(l));
0109         if bLOCKsTRUCT(l) < 0
0110           F{l,k+1}=sparse(zeros(bsize,1));
0111         else
0112           F{l,k+1}=sparse(zeros(bsize));
0113         end
0114       end
0115       if bLOCKsTRUCT(l) < 0
0116         F{l,k+1}(i)=value;
0117       else
0118         if i < j
0119           F{l,k+1}(i,j)=value;
0120           F{l,k+1}(j,i)=value;
0121         elseif i == j
0122           F{l,k+1}(i,j)=value;
0123         end
0124       end
0125     else 
0126       break;
0127     end
0128   end
0129 else
0130   % dense format case
0131   for k=1:mDIM+1
0132     for l=1:nBLOCK
0133       bsize=abs(bLOCKsTRUCT(l));
0134       if bLOCKsTRUCT(l) > 0
0135         F{l,k}=zeros(bsize);
0136         for i=1:bsize
0137           for j=1:bsize
0138             [value,cnt]=fscanf(fid,'%*[^0-9+-]%lg',1);
0139             if cnt
0140               F{l,k}(i,j)=value;
0141             else
0142               error(sprintf('Failed to read an element at %d %d %d %d'),...
0143             k-1,l,i,j);
0144             end
0145           end
0146         end
0147       else
0148         F{l,k}=zeros(bsize,1);
0149         for i=1:bsize
0150           [value,cnt]=fscanf(fid,'%*[^0-9+-]%lg',1);
0151           if cnt
0152             F{l,k}(i)=value;
0153           else
0154             error(sprintf('Failed to read an element at %d %d %d %d'),...
0155               k-1,l,i,i);
0156           end
0157         end
0158       end
0159     end
0160   end
0161 end
0162 fclose(fid);
0163 
0164 % How to treat 1-dim blocks - exclude into the linear inequality block?
0165 %linblk=find(bLOCKsTRUCT<0 | bLOCKsTRUCT==1);
0166 linblk=find(bLOCKsTRUCT<0);
0167 matr=setdiff(1:nBLOCK,linblk);
0168 sdpdata.Ng=sum(abs(bLOCKsTRUCT(linblk)));
0169 
0170 %linblk
0171 %matr
0172 
0173 % this might not work if linblk has more than 1 element
0174 % do blocks one by one + perhaps use vertcat (instead of horzcat [])
0175 %B=[F{linblk,2:end}];
0176 %d=[F{linblk,1}];
0177 
0178 B=[]; d=[];
0179 % still doesn't work (see truss1) - some of the matrices (columns in B) are
0180 % empty instead of zeros -> won't concatenate the columns correctly
0181 % ==> modify F and substitute empty matrices by zero matrices
0182 if (~isempty(linblk))
0183   for k=linblk
0184     sz=abs(bLOCKsTRUCT(k));
0185     for i=1:mDIM+1
0186       if (isempty(F{k,i}))
0187         F{k,i} = sparse(sz, 1); % in linblk ==> it is just a vector, not a matrix
0188       end
0189     end
0190   end
0191   for k=linblk
0192     Bk=[F{k,2:end}];   % should be a matrix dim_of_kth_block x mDIM
0193     dk=[F{k,1}];       % should be a vector dim_of_kth_block x 1
0194     % check dimensions if concatenated properly
0195     if (size(Bk,1)~=abs(bLOCKsTRUCT(k)) || size(Bk,2)~=mDIM)
0196       disp(sprintf('ERR: wrong dimensions of Bk, k=%i: %i %i',k,size(Bk)))
0197     end
0198     if (size(dk,1)~=abs(bLOCKsTRUCT(k)) || size(dk,2)~=1)
0199       disp(sprintf('ERR: wrong dimensions of dk, k=%i: %i %i',k,size(dk)))
0200     end
0201     % vertical concatenation
0202     B=[B;Bk];
0203     d=[d;dk];
0204   end
0205 end
0206 
0207 %size(B)
0208 %size(d)
0209 
0210 % apply the same fix for the first blocks ("absolute term"), the others are covered by Adep
0211 for k=matr
0212   sz=bLOCKsTRUCT(k);
0213   if (isempty(F{k,1}))
0214     F{k,1}=sparse(sz,sz);
0215   end
0216 end
0217 
0218 % probably won't work as F{k,i}... if F{k,i} is empty it won't add a column :(
0219 % better [F{k,:}]
0220 %B=[];
0221 %for k=linblk
0222 %  D=[];
0223 %  for i=2,mDIM+1
0224 %    D=[D, F{k,i}]
0225 %  end
0226 %  B=[B;D]
0227 %end
0228 
0229 sdpdata.name=filename;
0230 sdpdata.Nx=mDIM;
0231 sdpdata.Na=length(matr);  %nBLOCK;
0232 sdpdata.B=B;
0233 sdpdata.d=d;
0234 sdpdata.c=c;
0235 sdpdata.NaDims=bLOCKsTRUCT(matr);
0236 sdpdata.A=F(matr,:);
0237 
0238 % create dependency table, Adep(k) = vector of all x indices which Ak depends on
0239 sdpdata.Adep=cell(sdpdata.Na,1);
0240 for k=1:sdpdata.Na
0241   list=[];
0242   for i=2:mDIM+1
0243     if (~isempty(sdpdata.A{k,i}) && nnz(sdpdata.A{k,i})>0)
0244       list=[list,i-1];
0245     end
0246   end
0247   sdpdata.Adep{k}=list;
0248 end
0249 
0250 sdpdata.origF=F;
0251 sdpdata.origNaDims=bLOCKsTRUCT;
0252 
0253 % End of File
readsdpa_old

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