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1 function ndx = subv2indKPM(siz, subv)
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2 % SUBV2IND Like the built-in sub2ind, but the subscripts are given as row vectors.
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3 % ind = subv2ind(siz,subv)
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4 %
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5 % siz can be a row or column vector of size d.
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6 % subv should be a collection of N row vectors of size d.
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7 % ind will be of size N * 1.
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8 %
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9 % Example:
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10 % subv = [1 1 1;
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11 % 2 1 1;
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12 % ...
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13 % 2 2 2];
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14 % subv2ind([2 2 2], subv) returns [1 2 ... 8]'
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15 % i.e., the leftmost digit toggles fastest.
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16 %
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17 % See also IND2SUBV.
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18
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19
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20 if isempty(subv)
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21 ndx = [];
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22 return;
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23 end
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24
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25 if isempty(siz)
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26 ndx = 1;
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27 return;
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28 end
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29
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30 [ncases ndims] = size(subv);
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31
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32 %if length(siz) ~= ndims
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33 % error('length of subscript vector and sizes must be equal');
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34 %end
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35
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36 if all(siz==2)
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37 %rbits = subv(:,end:-1:1)-1; % read from right to left, convert to 0s/1s
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38 %ndx = bitv2dec(rbits)+1;
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39 twos = pow2(0:ndims-1);
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40 ndx = ((subv-1) * twos(:)) + 1;
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41 %ndx = sum((subv-1) .* twos(ones(ncases,1), :), 2) + 1; % equivalent to matrix * vector
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42 %ndx = sum((subv-1) .* repmat(twos, ncases, 1), 2) + 1; % much slower than ones
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43 %ndx = ndx(:)';
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44 else
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45 %siz = siz(:)';
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46 cp = [1 cumprod(siz(1:end-1))]';
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47 %ndx = ones(ncases, 1);
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48 %for i = 1:ndims
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49 % ndx = ndx + (subv(:,i)-1)*cp(i);
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50 %end
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51 ndx = (subv-1)*cp + 1;
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52 end
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53
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54 %%%%%%%%%%%
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55
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56 function d = bitv2dec(bits)
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57 % BITV2DEC Convert a bit vector to a decimal integer
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58 % d = butv2dec(bits)
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59 %
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60 % This is just like the built-in bin2dec, except the argument is a vector, not a string.
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61 % If bits is an array, each row will be converted.
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62
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63 [m n] = size(bits);
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64 twos = pow2(n-1:-1:0);
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65 d = sum(bits .* twos(ones(m,1),:),2);
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66
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