MATLAB: Control Break Processing

logical indexing

[EDIT: 20110720 16:05 CDT – reformat – WDR]
I have 3 column vectors (Date1 Date2 and Error) and what I want to do is create the column named Target. Target is a 1 if it is the smallest error by Date1 and Date2 AND error is < .10 otherwise its a 0.
I can do this using for loops, BUT I was wondering if I can do this using logical indexing….I am guessing that this will be faster since I won't have to nest3 for loops.
Date1             Date2  error  Target
'06-Nov-2000'  '16-Dec-2000'  0.47  0
'06-Nov-2000'  '16-Dec-2000'  0.41  0
'06-Nov-2000'  '16-Dec-2000'  0.29  0
'06-Nov-2000'  '16-Dec-2000'  0.14  0
'06-Nov-2000'  '16-Dec-2000'  0.03  1
'06-Nov-2000'  '16-Dec-2000'  0.18  0
'06-Nov-2000'  '18-Nov-2000'  0.03  1
'06-Nov-2000'  '18-Nov-2000'  0.31  0
'06-Nov-2000'  '18-Nov-2000'  0.44  0
'06-Nov-2000'  '18-Nov-2000'  0.45  0
'06-Nov-2000'  '18-Nov-2000'  0.44  0
'06-Nov-2000'  '18-Nov-2000'  0.44  0
'06-Nov-2000'  '18-Nov-2000'  0.45  0
'06-Nov-2000'  '18-Nov-2000'  0.45  0
'07-Nov-2000'  '18-Nov-2000'  0.36  0
'07-Nov-2000'  '18-Nov-2000'  0.09  1
'07-Nov-2000'  '18-Nov-2000'  0.15  0
'07-Nov-2000'  '18-Nov-2000'  0.38  0
'07-Nov-2000'  '18-Nov-2000'  0.48  0
'07-Nov-2000'  18-Dec-2000'  0.50  0
'07-Nov-2000'  18-Dec-2000'  0.01  1
'07-Nov-2000'  18-Dec-2000'  0.15  0

Best Answer

I have one solution but it still requires a for-loop.
raw={'06-Nov-2000'  '16-Dec-2000'  0.47  0
'06-Nov-2000'  '16-Dec-2000'  0.41  0
'06-Nov-2000'  '16-Dec-2000'  0.29  0
'06-Nov-2000'  '16-Dec-2000'  0.14  0
'06-Nov-2000'  '16-Dec-2000'  0.03  1
'06-Nov-2000'  '16-Dec-2000'  0.18  0
'06-Nov-2000'  '18-Nov-2000'  0.03  1
'06-Nov-2000'  '18-Nov-2000'  0.31  0
'06-Nov-2000'  '18-Nov-2000'  0.44  0
'06-Nov-2000'  '18-Nov-2000'  0.45  0
'06-Nov-2000'  '18-Nov-2000'  0.44  0
'06-Nov-2000'  '18-Nov-2000'  0.44  0
'06-Nov-2000'  '18-Nov-2000'  0.45  0
'06-Nov-2000'  '18-Nov-2000'  0.45  0
'07-Nov-2000'  '18-Nov-2000'  0.36  0
'07-Nov-2000'  '18-Nov-2000'  0.09  1
'07-Nov-2000'  '18-Nov-2000'  0.15  0
'07-Nov-2000'  '18-Nov-2000'  0.38  0
'07-Nov-2000'  '18-Nov-2000'  0.48  0
'07-Nov-2000'  '18-Dec-2000'  0.50  0
'07-Nov-2000'  '18-Dec-2000'  0.01  1
'07-Nov-2000'  '18-Dec-2000'  0.15  0};
% Date1 is your first column, nx1 cell array of strings
% Date2 is your second column, nx1 cell array of strings.
% Err is your third column, nx1 double array
Date1=raw(:,1);
Date2=raw(:,2);
Err=cell2mat(raw(:,3));
RawTarget=cell2mat(raw(:,4));
Target=false(size(Err));
Date=cellstr(cell2mat([Date1,Date2]));
UniqueDate=unique(Date);
for k=1:length(UniqueDate)
    Index=ismember(Date,UniqueDate(k));
    Loc=find(Index);
    [Dummy,MinIndex]=min(Err(Index));
    Target(Loc(MinIndex))=true;
end
Target=and(Target, Err<0.1);
all(Target==RawTarget)
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