Renumber matrix with some restrictions

Hello everyone,

i have a problem with a matrix called conn which represents the names of some cordinates.

The conn matrix is: conn=[1 5; 5 6; 6 7; 7 2; 2 3; 2 8; 8 9 ; 9 10; 10 4]

i want to renumber it from the start so the new matrix Con would be:

Con = [1 2; 2 3; 3 4; 4 5; 5 6; 5 7; 7 8 ; 8 9; 9 10].

So i want to renumber it from start row by row but all the same numbers from conn matrix apprear in the Con with the same number (see 2 3 and 2 8 from conn). Is it possible?

Thanks in advance.

Answer 1

[Walter Roberson]

conn=[1 5; 5 6; 6 7; 7 2; 2 3; 2 8; 8 9 ; 9 10; 10 4]

conn = 9×2

1 5 5 6 6 7 7 2 2 3 2 8 8 9 9 10 10 4

[~, ~, ic] = unique(conn.', 'stable')

ic = 18×1

1 2 2 3 3 4 4 5 5 6

Con = reshape(ic, 2, []).'

Con = 9×2

1 2 2 3 3 4 4 5 5 6 5 7 7 8 8 9 9 10

[Antonis Ventouris]

you are a star! thank you!

Answer 2

[Steven Lord]

I'm not completely sure how you got from conn to Con, in particular I'm not sure how you generated the third row in Con. [3 4] doesn't appear as a row in conn. What I think from your description you want uses sort and sortrows.

conn=[1 5; 5 6; 6 7; 7 2; 2 3; 2 8; 8 9 ; 9 10; 10 4]

conn = 9×2

1 5 5 6 6 7 7 2 2 3 2 8 8 9 9 10 10 4

smallerNumbersFirstInRow = sort(conn, 2)

smallerNumbersFirstInRow = 9×2

1 5 5 6 6 7 2 7 2 3 2 8 8 9 9 10 4 10

Con = sortrows(smallerNumbersFirstInRow)

Con = 9×2

1 5 2 3 2 7 2 8 4 10 5 6 6 7 8 9 9 10

If that's not what you want can you describe in more detail exactly how you generated your Con matrix from the conn matrix?