Repair non-working example.py and speed-test

The introduction of the allow_writes parameter in larch/forest.py:open_forest()
broke example.py and speed-test.
Just adding the parameter to the open_forest calls was not enough to fix the
issue.  This patch fixes the issue by adding the allow_writes parameter where it
is needed beyond the open_forest calls.

Most notably, this patch changes the __init__ signature of the abstract base 
class larch.NodeStore from __init__(self, node_size, codec) to
__init__(self, allow_writes, node_size, codec)

This mimicks the current signatures of NodeStoreDisk and NodeStoreMemory, which
include the use of allow_writes as first parameter, and which seem required
to actually create a forest anyway since forest.py creates node_store instances 
with allow_writes as first parameter in open_forest

1 files changed, 9 insertions, 5 deletions

diff --git a/speed-test b/speed-test
index 5351a82..4d6ffab 100755
--- a/speed-test
+++ b/speed-test
@@ -15,8 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Excercise my B-tree implementation, for simple benchmarking purposes.
-# The benchmark gets a location and an operation count as command line
-# arguments.
+# The benchmark gets a location and nb of keys to use as command line
+# arguments --location=LOCATION and --keys=KEYS.
 #
 # If the location is the empty string, an in-memory node store is used.
 # Otherwise it must be a non-existent directory name.
@@ -73,13 +73,13 @@ class SpeedTest(cliapp.Application):
             raise Exception('You must set number of keys with --keys')
         
         if not location:
-            forest = larch.open_forest(key_size=key_size, node_size=node_size,
+            forest = larch.open_forest(allow_writes=True, key_size=key_size, node_size=node_size,
                                        node_store=larch.NodeStoreMemory)
         else:
             if os.path.exists(location):
                 raise Exception('%s exists already' % location)
             os.mkdir(location)
-            forest = larch.open_forest(key_size=key_size, node_size=node_size,
+            forest = larch.open_forest(allow_writes=True, key_size=key_size, node_size=node_size,
                                        dirname=location)
 
         tree = forest.new_tree()
@@ -144,7 +144,11 @@ class SpeedTest(cliapp.Application):
 
         # Report
         def speed(result, i):
-            return n / (result[i] - looptime[i])
+            if result[i] == looptime[i]:
+                # computer too fast for the number of "keys" used...
+                return float("infinity")
+            else:
+                return n / (result[i] - looptime[i])
         def report(label, result):
             cpu, wall = result
             print '%-16s: %5.3f s (%8.1f/s) CPU; %5.3f s (%8.1f/s) wall' % \