# Decide on ordering for Gang of Four equations and plots

Issue #60 resolved
Richard Murray repo owner created an issue

In various places in the text we have all four of the Gang of Four transfer functions, but we seem to use different ordering in different places. Some examples:

• When we define the sensitivity functions in Chapter 12 (page 12-3), we give a 2x2 matrix of transfer functions in the following order (left to right, then top to bottom): S & PS \\ T & CS (note that this is the first place they are defined and it might make sense to list S and T in the first column, even if it is inconsistent with other uses)
• In Example 12.1 (page 12-5) we list them as T & PS \\ CS & S
• In Figure 12.10 (page 12-17) we plot the gang of four in the order S & PS \\ CS & T
• In Figure 12.22 (page 12-31) we plot the gang of four in the order S & PS \\ CS & T (this comes from the custom MATLAB function gangof4)
• In Chapter 13 in the section on the Youla parameterization (page 13-14), we list the functions as a single row: S, PS, CS, T
• On the next page we lay these out in a matrix: S & PS \\ CS & T
• In Example 13.11 we plot the Gang of Four in Figure 13.13 (page 13-20): the order is S & PS \\ CS & T
• In Figure 13.14 (page 13-22) the order is S & PS \\ CS & T
• In Figure 14.13 (page 14-25) the order is S & PS \\ CS & T

From these, it appears that the outlier is the original definition on page 12-3 (which I think is probably OK) and Example 12.1 on page 12-5.

1. reporter

Updated Example 12.1 to be consistent with the other examples (and MATLAB function) in commit 43dbd23. Leaving this in place to confirm this is OK with Karl.

2. reporter
3. reporter

24 Jul: Karl OK with change.

4. reporter

All plots are now consistent: S, PS \ CS, T.