Biuld Min Index Array from Two dimensional Array

Hi Guys,

I got a question on Matlab. I am trying to build Array of min values from Two dimensional Array. Basically, the idea is to look for minimum value at each column & record the index.

If there are more then one minimum value then record it in different array, but the new array upto that point should be similar to previous one.

Its like finding minimum values link from mxn array.

Can you please help me to efficiently code this?

Thanks

Answer 1

[Sean de Wolski]

[junk, index] = min(your_matrix);  %will get you the first index

To get all minimum indices:

A = magic(4); %sample
A(7) = 2; %set duplicate for example
[r c] = find(bsxfun(@eq,min(A),A)); %all column mins
colmindex = accumarray(c,r,[],@(x){x})' %bin them into a row vector cell array with each index

Answer 2

[Ruk Niz]

Hi Sean, Thanks for reply. This gives me the first Minimum at each column.

I am hoping to build multiple level of index. If say one column contains more than 1 minimum then I would like to create multiple single index array.

Say A =

     0     0     1     2     3     4
     2     3     1     3     4     1
     1     1     2     0     3     7

>> [junk, index] = min(A)

junk =

     0     0     1     0     3     1

index =

     1     1     1     3     1     2

Gives only the first minimum index but if you look at the matrix. I am hoping to get the following

index1 = 1 1 1 3 1 2 index2 = 1 1 2 3 1 2 index3 = 1 1 1 3 3 2 index4 = 1 1 2 3 3 2

same for junk variable.

Rdgs Ruk

[Sean de Wolski]

See the update... and perhaps the FAQ on why to avoid using index1...4