index array to access the value in matrix

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AniCnx
AniCnx 2019-11-14
评论： AniCnx 2019-11-15
Hi all, I have 3 matrixes as matrix IM (200x200); X(400x400); Y(400x400). As matrix x and y is indexing the matrix IM. How can I use x and y matrix to access the value of matrix IM withouf for loop.
  2 个评论
Shubham Gupta
Shubham Gupta 2019-11-14
Can you please share mat file or put a small example to show what is stored in X,Y & IM?
Small example can be like X&Y of size 4x4 & IM being 2x2, then you can show desired output for this example.
AniCnx
AniCnx 2019-11-14
IM=4.08809852121212 4.29250344727273 4.39470591030303 4.44580714181818 4.44580714181818 4.54800960484849 4.65021206787879 4.75241453090909 4.80351576242424 4.95681945696970
4.39470591030303 4.44580714181818 4.49690837333333 4.54800960484849 4.59911083636364 4.65021206787879 4.75241453090909 4.80351576242424 4.85461699393939 4.95681945696970
4.34360467878788 4.44580714181818 4.49690837333333 4.59911083636364 4.59911083636364 4.65021206787879 4.75241453090909 4.80351576242424 4.80351576242424 4.90571822545455
4.34360467878788 4.39470591030303 4.49690837333333 4.59911083636364 4.59911083636364 4.70131329939394 4.75241453090909 4.75241453090909 4.75241453090909 4.85461699393939
4.29250344727273 4.39470591030303 4.44580714181818 4.54800960484849 4.59911083636364 4.70131329939394 4.70131329939394 4.75241453090909 4.80351576242424 4.80351576242424
4.29250344727273 4.34360467878788 4.44580714181818 4.54800960484849 4.59911083636364 4.70131329939394 4.75241453090909 4.75241453090909 4.80351576242424 4.80351576242424
4.29250344727273 4.34360467878788 4.39470591030303 4.49690837333333 4.59911083636364 4.70131329939394 4.75241453090909 4.80351576242424 4.80351576242424 4.80351576242424
4.29250344727273 4.34360467878788 4.39470591030303 4.49690837333333 4.59911083636364 4.75241453090909 4.75241453090909 4.75241453090909 4.80351576242424 4.80351576242424
4.34360467878788 4.34360467878788 4.39470591030303 4.49690837333333 4.59911083636364 4.70131329939394 4.80351576242424 4.80351576242424 4.80351576242424 4.85461699393939
4.44580714181818 4.44580714181818 4.39470591030303 4.49690837333333 4.59911083636364 4.70131329939394 4.75241453090909 4.75241453090909 4.80351576242424 4.80351576242424
x=1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4
5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7
7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7
8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8
8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8
9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9
9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9
10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
y=1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10

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采纳的回答

Shubham Gupta
Shubham Gupta 2019-11-14
Step1 - Convert the subscript to indeces using x & y(Hint: sub2ind)
Step2 - Calculate values of IM for calculated indeces
Step3 - Reshape it to match the dimesion with x or y (Hint: reshape)
Something like this:
output = reshape(IM(sub2ind(size(IM),x(:),y(:))),size(x,1),size(x,2));
Let me know if you have doubt

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