From 76df6ec88fa65709381ab6e00a93cfaeb95fa749 Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Fri, 5 Dec 2008 03:31:45 +0000
Subject: [PATCH] optimise cacheLedger by using the tree to help calculate
 account balances from:

	total time  =        0.14 secs   (7 ticks @ 20 ms)
	total alloc = 275,520,536 bytes  (excludes profiling overheads)

     cacheLedger                                     1   0.0    0.1      42.9       48.6
      sumTransactions                                0   0.0    0.6      28.6       42.5
       isZeroAmount                              13529   0.0    2.0      14.3       39.2
        showAmount                               13529   0.0    7.2      14.3       37.2
         showAmount'                             13529  14.3   29.9      14.3       29.9
         con2tag_Side#                           27232   0.0    0.0       0.0        0.0
       normaliseMixedAmount                       6733   0.0    1.8      14.3        2.7
        con2tag_Side#                              120   0.0    0.0       0.0        0.0
        sumAmountsPreservingPrice                 6803   0.0    0.2      14.3        1.0
         amountop                                13351   0.0    0.4      14.3        0.8
          convertAmountTo                        13351  14.3    0.4      14.3        0.4
           conversionRate                        13351   0.0    0.0       0.0        0.0
      isAccountNamePrefixOf                      25122   0.0    2.0       0.0        2.0

to:

	total time  =        0.08 secs   (4 ticks @ 20 ms)
	total alloc = 168,637,964 bytes  (excludes profiling overheads)

     cacheLedger                                     1   0.0    0.1       0.0       27.1
      sumTransactions                                0   0.0    0.3       0.0       18.8
       isZeroAmount                               3931   0.0    0.9       0.0       17.3
        showAmount                                3931   0.0    3.4       0.0       16.3
         showAmount'                              3931   0.0   12.9       0.0       12.9
         con2tag_Side#                            7884   0.0    0.0       0.0        0.0
       normaliseMixedAmount                       1964   0.0    0.8       0.0        1.3
        con2tag_Side#                               12   0.0    0.0       0.0        0.0
        sumAmountsPreservingPrice                 1970   0.0    0.1       0.0        0.5
         amountop                                 3793   0.0    0.2       0.0        0.4
          convertAmountTo                         3793   0.0    0.2       0.0        0.2
           conversionRate                         3793   0.0    0.0       0.0        0.0
---
 Ledger/Ledger.hs | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/Ledger/Ledger.hs b/Ledger/Ledger.hs
index c3258a1bb..6858b203c 100644
--- a/Ledger/Ledger.hs
+++ b/Ledger/Ledger.hs
@@ -35,15 +35,26 @@ cacheLedger apats l = Ledger{rawledgertext="",rawledger=l,accountnametree=ant,ac
     where
       ts = filtertxns apats $ rawLedgerTransactions l
       ant = rawLedgerAccountNameTree l
+
       anames = flatten ant
       txnmap = Map.union (transactionsByAccount ts) (Map.fromList [(a,[]) | a <- anames])
-      subacctsof a = filter (a `isAccountNamePrefixOf`) anames
-      subtxnsof a = concat [txnmap ! a | a <- [a] ++ subacctsof a]
-      balmap = Map.union 
-               (Map.fromList [(a,sumTransactions $ subtxnsof a) | a <- anames]) 
-               (Map.fromList [(a,Mixed []) | a <- anames])
+      txnsof = (txnmap !)
+
+      -- add subaccount-including balances to a tree of account names
+      -- somewhat efficiently
+      addbalances :: Tree AccountName -> Tree (AccountName, MixedAmount)
+      addbalances (Node a []) = Node (a,sumTransactions $ txnsof a) []
+      addbalances (Node a subs) = Node (a,sumtxns + sumsubaccts) subbals
+          where
+            sumtxns = sumTransactions $ txnsof a
+            sumsubaccts = sum $ map (snd . root) subbals
+            subbals = map addbalances subs
+      balmap = Map.fromList $ flatten $ addbalances ant
+      balof = (balmap !)
+
+      mkacct a = Account a (txnsof a) (balof a)
       acctmap = Map.fromList [(a, mkacct a) | a <- anames]
-      mkacct a = Account a (txnmap ! a) (balmap ! a)
+
 
 -- | Convert a list of transactions to a map from account name to the list
 -- of all transactions in that account.