From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 13 May 2012 12:59:43 +0000 (+0100)
Subject: strategy: new, wip
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=topbloke-formulae.git;a=commitdiff_plain;h=f0f7eceb4c3b65e4728d0b04b23e28906d5038fb

strategy: new, wip
---

diff --git a/article.tex b/article.tex
index 18c75df..eb490e6 100644
--- a/article.tex
+++ b/article.tex
@@ -50,6 +50,10 @@
 \newcommand{\pcy}{\pay{C}}
 \newcommand{\pcn}{\pan{C}}
 
+\newcommand{\pd}{\pa{D}}
+\newcommand{\pdy}{\pay{D}}
+\newcommand{\pdn}{\pan{D}}
+
 \newcommand{\pl}{\pa{L}}
 \newcommand{\ply}{\pay{L}}
 \newcommand{\pln}{\pan{L}}
diff --git a/strategy.tex b/strategy.tex
index 6fb4b4f..d9a2545 100644
--- a/strategy.tex
+++ b/strategy.tex
@@ -91,7 +91,7 @@ We run the following algorithm:
 \item Set $\allpatches = \{ \}$.
 \item Repeatedly:
 \begin{enumerate}
-\item Clear out the graph $\hasdirdep$ so it has neither nodes nor edges.
+\item Clear out the graph $\hasdirdep$ so it has no edges.
 \item Execute {\bf Rank-Recurse}($\pc_0$)
 \item Until $\allpatches$ remains unchanged.
 \end{enumerate}
@@ -99,21 +99,85 @@ We run the following algorithm:
 
 {\bf Rank-Recurse}($\pc$) is:
 \begin{enumerate}
+
+\item If we have already done {\bf Rank-Recurse}($\pc$) in this
+ranking iteration, do nothing.  Otherwise:
+
 \item Add $\pc$ to $\allpatches$ if it is not there already.
-\item Let $\set S_{\pcn} = h(\pcn)
+
+\item Let
+$$
+  \set S = h(\pcn)
      \cup 
         \bigcup_{\p \in \allpatches}
         \bigcup_{H \in h(\pn) \lor H \in h(\py)}
-         \{ \baseof{E} \; | \; E \in \pendsof{H}{\pcy} \} $
+         \{ \baseof{E} \; | \; E \in \pendsof{H}{\pcy} \}
+$$
 
 and $W = w(h(\pcn))$
 
-We write $\set S = \set S_{\pcn}$ where unambiguous.
-\item While $\exists_{S \in \set S} S \ge W$:
+\item While $\exists_{S \in \set S} S \ge W$,
+update $W \assign S$ and $\set S \assign \set S \, \backslash \{ S \}$
+
+(This will often remove $W$ from $\set S$.  Afterwards, $\set S$
+is a collection of heads to be merged into $W$.)
+
+\item Choose an order of $\set S$, $S_i$ for $i=1 \ldots n$.
+
+\item For each $S_i$ in turn, choose a corresponding $M_i$
+such that $$
+   M_i \le S_i \land \left[
+   M_i \le W \lor \bigexists_{S_i, j<i} M_i \le s_i
+   \right]
+$$
+
+\item Set $\Gamma = \depsreqof{W}$.
+
+If there are multiple candidates we prefer $M_i \in \pcn$
+if available.
+
+\item For each $i \ldots 1..n$, update our putative direct
+dependencies:
+$$
+\Gamma \assign \text{\bf set-merge}\left(\Gamma, 
+ \left[ \begin{cases} 
+  M_i \in \pcn :     & \depsreqof{M_i} \\
+  M_i \not\in \pcn : & \{ \}
+ \end{cases} \right],
+ \depsreqof{S_i}
+ \right)
+$$
+
+\item Finalise our putative direct dependencies
+$
+\Gamma \assign g(\pc, \Gamma)
+$
+
+\item For each direct dependency $\pd \in \Gamma$,
+
+\begin{enumerate}
+\item Add an edge $\pc \hasdirdep \pd$ to the digraph (adding nodes
+as necessary).
+If this results in a cycle, abort entirely (as the function $g$ is
+inappropriate; a different $g$ could work.)
+\end{enumerate}
+\item Run ${\text{\bf Rank-Recurse}}(\pd)$.
 
-Update $W \assign S$ and $\set S \assign \set S \, \backslash \{ S \}$
 \end{enumerate}
 
+The results of the ranking phase are:
+
+$ \allpatches, \hasdirdep $ and hence the completion of $\hasdirdep$
+into the partial order $\hasdep$.
+
+For each $\pc$, the base branch starting point commit $W_{\pcn} = W$,
+the direct dependencies $\Gamma_{\pc}$,
+the ordered set of base branch sources $\set S_{\pcn} = \set S,
+S_{\pcn,i} = S_i$
+and corresponding merge bases $M_{\pcn,i} = M_i$.
+
+
+
 \section{Planning phase}
 
 The results of the planning phase consist of: