index array to access the value in matrix

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.

[Shubham Gupta]

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]

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

Answer 1

[Shubham Gupta]

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

[AniCnx]

Thank you very much. it works very well.