Vectorize a for loop and if-else statement

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shahrizan jamaludin 2016-3-10

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/272525-vectorize-a-for-loop-and-if-else-statement

评论： shahrizan jamaludin 2016-3-11

Hello. Can anybody help me to vectorize:

L=1;
A=0;
for L=1:100
 for i=1:25
  A=A+1;
  if E(L).a == N(i).a
     HD(A,L)=myfunction(T0,M0,T(i).a,M(i).a);
  else
     HD(A,L)=0;
  end
  A=A+1;
  if E(L).a == N(i).b
     HD(A,L)=myfunction(T0,M0,T(i).b,M(i).b);
  else
     HD(A,L)=0;
  end
end
end

where E,N,T,M are struct. T0 and M0 are 128x720 double. Thanks

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shahrizan jamaludin 2016-3-10

在 MATLAB Online 中打开

This is myfunction

function hd = myfunction(template1, mask1, template2, mask2)
[ro,co]=size(template1);
num=co/2;
scales=1;
template1 = logical(template1);
mask1 = logical(mask1);
template2 = logical(template2);
mask2 = logical(mask2);
hd = NaN;
for shifts=-8:8
  template1s = shiftbits(template1, shifts,scales);
  mask1s = shiftbits(mask1, shifts,scales);
  mask = mask1s | mask2;
  nummaskbits = sum(sum(mask == 1));
  totalbits = (size(template1s,1)*size(template1s,2))- nummaskbits;
  C = xor(template1s,template2);
  C = C & ~mask;
  bitsdiff = sum(sum(C==1));
  if totalbits == 0
      hd = NaN;
  else
      hd1 = bitsdiff / totalbits;
      if  hd1 < hd || isnan(hd)
          hd = hd1;
      end
  end
end

shiftbits function

function templatenew = shiftbits(template, noshifts,nscales)
templatenew = zeros(size(template));
width = size(template,2);
s = round(2*nscales*abs(noshifts));
p = round(width-s);
if noshifts == 0
  templatenew = template;
      % if noshifts is negatite then shift towards the left
elseif noshifts < 0
  x=1:p;
  templatenew(:,x) = template(:,s+x);
  x=(p + 1):width;
  templatenew(:,x) = template(:,x-p);
else
  x=(s+1):width;
  templatenew(:,x) = template(:,x-s);
  x=1:s;
  templatenew(:,x) = template(:,p+x);
end