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Sample Input

file name
0.00 -1.0000 number1
0.00 -0.8000 number2
0.00 -0.6000 number3
0.00 -0.4000 number4
0.00 -0.2000 number5
0.00 0.0000 number6
0.00 0.2000 number7
0.00 0.4000 number8
0.00 0.6000 number9
0.00 0.8000 number10
0.00 1.0000 number11

0.02 -1.0000 number12
0.02 -0.8000 number13
0.02 -0.6000 number14
0.02 -0.4000 number15
0.02 -0.2000 number16
0.02 0.0000 number17
0.02 0.2000 number18
0.02 0.4000 number19
0.02 0.6000 number20
0.02 0.8000 number21
0.02 1.0000 number22

0.04 -1.0000 number23
0.04 -0.8000 number24
0.04 -0.6000 number25
0.04 -0.4000 number26
0.04 -0.2000 number27
0.04 0.0000 number28
0.04 0.2000 number29
0.04 0.4000 number30
0.04 0.6000 number31
0.04 0.8000 number32
0.04 1.0000 number33

goal

(Referring to columns/fields in awk nomenclature, ie. $1 = field 1)

As you can see, there are 3 blocks of data above. Within each block, $1 equals a constant value. For each block of $1 = constant, I would like to exchange $3 symmetrically around where $2 = 0. The result would be the following desired output:

desired output

file name
0.00 -1.0000 number11
0.00 -0.8000 number10
0.00 -0.6000 number9
0.00 -0.4000 number8
0.00 -0.2000 number7
0.00 0.0000 number6
0.00 0.2000 number5
0.00 0.4000 number4
0.00 0.6000 number3
0.00 0.8000 number2
0.00 1.0000 number1

0.02 -1.0000 number22
0.02 -0.8000 number21
0.02 -0.6000 number20
0.02 -0.4000 number19
0.02 -0.2000 number18
0.02 0.0000 number17
0.02 0.2000 number16
0.02 0.4000 number15
0.02 0.6000 number14
0.02 0.8000 number13
0.02 1.0000 number12

0.04 -1.0000 number33
0.04 -0.8000 number32
0.04 -0.6000 number31
0.04 -0.4000 number30
0.04 -0.2000 number29
0.04 0.0000 number28
0.04 0.2000 number27
0.04 0.4000 number26
0.04 0.6000 number25
0.04 0.8000 number24
0.04 1.0000 number23

background context

In my actual input, $1 continues in the sequence of 0.00..0.02..15.0. Furthermore, within each block, $2 proceeds as -14..0.2..14. Therefore, in total there are 751 blocks, and each block alone consists of 141 lines (or 142 lines, including the additional title/empty line preceding each block).

So it would be helpful to have a script that can go through each of the 751 blocks one-by-one, and reflect that block's $3 arbitrary values symmetrically around the median line for that individual block (the 71st line in each block, or 72nd including the empty line above each block).

Thank you!

You tagged this with bash, but mentioned awk, so I hope it's okay to use that:

$ awk -vn=0 'NR == 1 print; next
 $0 != "" k = $1; a[n] = $2; b[n] = $3; n++ 
 $0 == "" for (i = 0; i < n ; i++) 
 printf "%s %s %sn", k, a[i], b[n-i-1]; 
 n=0; print ' < data

On the very first line (NR == 1), we just print it and go on.

Then,
for nonempty lines, it loads the second and third fields to arrays a and b, and for empty lines, it goes through the arrays and prints a in order, and b in the inverse order and finally resets the counter n.

This assumes that (1) the point to mirror over is actually in the middle; (2) the first field is always the same within each block (as it is in your code); and (3) that there is an empty line after each block (though additional empty lines shouldn't matter. Add an empty line at the very end if you don't have one there).