How can I compare row by row to get rid if reciprocols and get corresponding indices

hello, I have a data matrix looks like below.

A=[4  5  0  0  0  10  0  15  0  0.19218
4  5  0  0  0  15  0  20  0  0.06548
4  5  0  0  0  20  0  25  0  0.02662
4  5  0  0  0  25  0  30  0  0.01446
4  5  0  0  0  30  0  35  0  0.00708
4  5  0  0  0  35  0  40  0  0.00487
4  15  0  10  0  20  0  25  0  0.31673
4  15  0  10  0  25  0  30  0  0.09447
4  15  0  10  0  30  0  35  0  0.03430
4  15  0  10  0  35  0  40  0  0.02008
4  15  0  10  0  40  0  45  0  0.01002
4  15  0  10  0  45  0  50  0  0.00502
4  15  0  10  0  50  0  5  0  0.33494
4  10  0  15  0  5  0  0  0  0.19150
4  20  0  15  0  25  0  30  0  0.43342
4  20  0  15  0  30  0  35  0  0.10293
4  20  0  15  0  35  0  40  0  0.04998
4  20  0  15  0  40  0  45  0  0.02261
4  20  0  15  0  45  0  50  0  0.01038
4  20  0  15  0  50  0  55  0  0.00523
4  20  0  15  0  55  0  10  0  0.54030
4  15  0  20  0  10  0  5  0  0.37795
4  15  0  20  0  5  0  0  0  0.06513
];

Basically,I want compare row by row based on column [ 2 4 6 8]. for example,first row column 2,4, 6,8 is 5,0,10,15. and the 14th row column 2,4,6,8 is 10,15,5,0. In this case, I need the index of the two rows since I only want one row. For a second example,please compare 2nd and 15th row,2nd row has 5,0,15,20 and 15th row has 15,20,5,0. This is just part of my data, I have many reciprocol measurements which is roughly the same as I showed above.If anyone knows how can I solve this problem,please let me know. I do not want change the order of my data. Thanks

Answer 1

[Sean de Wolski]

Look at using the various outputs from unique().

doc unique

[Lei]

hello Sean,thx. But the unique function only compares one value of each row, I guess. For my case, I need to compare 2nd and 4th column of row 1 with column 6 and column 8 with all of the other rows. If the result is true, I need the row index of both rows.

[Sean de Wolski]

So use the 'rows' flag on the subset that you need. I.e. extract the columns you want to count and then look at unique rows of this. If you could make your example smaller with the expected results we might be able to help more. The matrix you show us is huge and we don't know what you expect.

Show us an example with a 5x4 matric and the results from it.

[Lei]

Hello Sean, Basically, I want compare this:

 A=[ 5 0 10 15 0.021
     5 0 15 20 0.011
     10 15 5 0 0.022
     15 20 5 0 0.009]

I need to compare first two columns of each row with the 3rd and 4th columns of all of the other rows.If the answer is true, I want the index of the two rows. So for this matrix, the comparison of row 1 and row 3 is true, same as row 2 and row 4,of coure, I need the index for both rows. But the other combinations, the comparisons are wrong.