From a25d4fb6e92f203183de2d89e8c467a6b14e1730 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex.auvolat@ens.fr>
Date: Mon, 27 Apr 2015 13:08:56 -0400
Subject: Implement HDist, transformer that selects k at a random position.

---
 data.py         |  8 ++++----
 hdist.py        | 25 +++++++++++++++++++++++++
 model.py        | 18 +++++++++++-------
 transformers.py | 19 ++++++++++++++-----
 4 files changed, 54 insertions(+), 16 deletions(-)
 create mode 100644 hdist.py

diff --git a/data.py b/data.py
index dd5e42e..8015054 100644
--- a/data.py
+++ b/data.py
@@ -69,7 +69,7 @@ class TaxiData(Dataset):
     def __init__(self, pathes, has_header=False):
         if not isinstance(pathes, list):
             pathes=[pathes]
-        assert len(pathes)
+        assert len(pathes)>0
         self.pathes=pathes
         self.has_header=has_header
         super(TaxiData, self).__init__()
@@ -101,12 +101,12 @@ class TaxiData(Dataset):
             raise ValueError
         try:
             line=state.reader.next()
-        except StopIteration:
-            print state.index
+        except (ValueError, StopIteration):
+            # print state.index
             state.file.close()
             state.index+=1
             if state.index>=len(self.pathes):
-                raise
+                raise StopIteration
             state.file=open(self.pathes[state.index])
             state.reader=csv.reader(state.file)
             if self.has_header:
diff --git a/hdist.py b/hdist.py
new file mode 100644
index 0000000..4944cb8
--- /dev/null
+++ b/hdist.py
@@ -0,0 +1,25 @@
+from theano import tensor
+import numpy
+
+
+def hdist(a, b):
+    rearth = numpy.float32(6371)
+    deg2rad = numpy.float32(3.14159265358979 / 180)
+
+    lat1 = a[:, 0] * deg2rad
+    lon1 = a[:, 1] * deg2rad
+    lat2 = b[:, 0] * deg2rad
+    lon2 = b[:, 1] * deg2rad
+
+    dlat = abs(lat1-lat2)
+    dlon = abs(lon1-lon2)
+
+    al = tensor.sin(dlat/2)**2  + tensor.cos(lat1) * tensor.cos(lat2) * (tensor.sin(dlon/2)**2)
+    d = tensor.arctan2(tensor.sqrt(al), tensor.sqrt(numpy.float32(1)-al))
+
+    hd = 2 * rearth * d
+
+    return tensor.switch(tensor.eq(hd, float('nan')), (a-b).norm(2, axis=1), hd)
+
+
+
diff --git a/model.py b/model.py
index 95b002f..a5c820e 100644
--- a/model.py
+++ b/model.py
@@ -24,6 +24,7 @@ from blocks.extensions.monitoring import DataStreamMonitoring
 
 import data
 import transformers
+import hdist
 
 n_dow = 7       # number of division for dayofweek/dayofmonth/hourofday
 n_dom = 31
@@ -38,8 +39,8 @@ n_end_pts = 5
 dim_embed = 50
 dim_hidden = 200
 
-learning_rate = 0.1
-batch_size = 32
+learning_rate = 0.01
+batch_size = 64
 
 def main():
     # The input and the targets
@@ -67,7 +68,8 @@ def main():
     outputs = output_layer.apply(hidden)
 
     # Calculate the cost
-    cost = (outputs - y).norm(2, axis=1).mean()
+    # cost = (outputs - y).norm(2, axis=1).mean()
+    cost = hdist.hdist(outputs, y).mean()
     cost.name = 'cost'
 
     # Initialization
@@ -84,14 +86,16 @@ def main():
     # Load the training and test data
     train = data.train_data
     train = DataStream(train)
-    train = transformers.add_extremities(train, n_begin_end_pts)
+    train = transformers.add_first_k(n_begin_end_pts, train)
+    train = transformers.add_random_k(n_begin_end_pts, train)
     train = transformers.add_destination(train)
     train = transformers.Select(train, ('origin_stand', 'origin_call', 'first_k', 'last_k', 'destination'))
     train_stream = Batch(train, iteration_scheme=ConstantScheme(batch_size))
 
     valid = data.valid_data
     valid = DataStream(valid)
-    valid = transformers.add_extremities(valid, n_begin_end_pts)
+    valid = transformers.add_first_k(n_begin_end_pts, valid)
+    valid = transformers.add_random_k(n_begin_end_pts, valid)
     valid = transformers.add_destination(valid)
     valid = transformers.Select(valid, ('origin_stand', 'origin_call', 'first_k', 'last_k', 'destination'))
     valid_stream = Batch(valid, iteration_scheme=ConstantScheme(batch_size))
@@ -107,8 +111,8 @@ def main():
 
     extensions=[DataStreamMonitoring([cost], valid_stream,
                                      prefix='valid',
-                                     every_n_batches=100),
-                Printing(every_n_batches=100),
+                                     every_n_batches=1000),
+                Printing(every_n_batches=1000),
                 # Dump('taxi_model', every_n_batches=100),
                 # LoadFromDump('taxi_model'),
                 ]
diff --git a/transformers.py b/transformers.py
index 29b8094..b6f5e14 100644
--- a/transformers.py
+++ b/transformers.py
@@ -1,6 +1,7 @@
 from fuel.transformers import Transformer, Filter, Mapping
 import numpy
 import theano
+import random
 
 class Select(Transformer):
     def __init__(self, data_stream, sources):
@@ -14,13 +15,21 @@ class Select(Transformer):
         data=next(self.child_epoch_iterator)
         return [data[id] for id in self.ids]
 
-def add_extremities(stream, k):
+def add_first_k(k, stream):
     id_polyline=stream.sources.index('polyline')
-    def extremities(x):
-        return (numpy.array(x[id_polyline][:k], dtype=theano.config.floatX).flatten(),
-                numpy.array(x[id_polyline][-k:], dtype=theano.config.floatX).flatten())
+    def first_k(x):
+        return (numpy.array(x[id_polyline][:k], dtype=theano.config.floatX).flatten(),)
     stream = Filter(stream, lambda x: len(x[id_polyline])>=k)
-    stream = Mapping(stream, extremities, ('first_k', 'last_k'))
+    stream = Mapping(stream, first_k, ('first_k',))
+    return stream
+
+def add_random_k(k, stream):
+    id_polyline=stream.sources.index('polyline')
+    def random_k(x):
+        loc = random.randrange(len(x[id_polyline])-k+1)
+        return (numpy.array(x[id_polyline][loc:loc+k], dtype=theano.config.floatX).flatten(),)
+    stream = Filter(stream, lambda x: len(x[id_polyline])>=k)
+    stream = Mapping(stream, random_k, ('last_k',))
     return stream
 
 def add_destination(stream):
-- 
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