From 181d30e8e3ac13a2211168cf569193aec61f490d Mon Sep 17 00:00:00 2001
From: Christopher Baldassano <chrisb@princeton.edu>
Date: Tue, 20 Feb 2018 09:19:32 -0500
Subject: [PATCH 1/4] Fixing bug in event segmentation code

---
 brainiak/eventseg/event.py   | 20 ++++++++++----------
 tests/.flake8                |  2 +-
 tests/eventseg/test_event.py | 14 ++++++++++++++
 3 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/brainiak/eventseg/event.py b/brainiak/eventseg/event.py
index e0c12abb5..4373addd9 100644
--- a/brainiak/eventseg/event.py
+++ b/brainiak/eventseg/event.py
@@ -268,23 +268,23 @@ def _forward_backward(self, logprob):
         p_end[0, -2] = 1
 
         # Forward pass
-        for t in range(t):
-            if t == 0:
+        for i in range(t):
+            if i == 0:
                 log_alpha[0, :] = self._log(p_start) + logprob[0, :]
             else:
-                log_alpha[t, :] = self._log(np.exp(log_alpha[t - 1, :])
-                                            .dot(P)) + logprob[t, :]
+                log_alpha[i, :] = self._log(np.exp(log_alpha[i - 1, :])
+                                            .dot(P)) + logprob[i, :]
 
-            log_scale[t] = np.logaddexp.reduce(log_alpha[t, :])
-            log_alpha[t] -= log_scale[t]
+            log_scale[i] = np.logaddexp.reduce(log_alpha[i, :])
+            log_alpha[i] -= log_scale[i]
 
         # Backward pass
         log_beta[-1, :] = self._log(p_end) - log_scale[-1]
-        for t in reversed(range(t - 1)):
-            obs_weighted = log_beta[t + 1, :] + logprob[t + 1, :]
+        for i in reversed(range(t - 1)):
+            obs_weighted = log_beta[i + 1, :] + logprob[i + 1, :]
             offset = np.max(obs_weighted)
-            log_beta[t, :] = offset + self._log(
-                np.exp(obs_weighted - offset).dot(P.T)) - log_scale[t]
+            log_beta[i, :] = offset + self._log(
+                np.exp(obs_weighted - offset).dot(P.T)) - log_scale[i]
 
         # Combine and normalize
         log_gamma = log_alpha + log_beta
diff --git a/tests/.flake8 b/tests/.flake8
index 49611972d..3c0105d98 100644
--- a/tests/.flake8
+++ b/tests/.flake8
@@ -12,5 +12,5 @@ ignore =
     W503,
     W504,
     # Print restriction only applies to libraries
-    T001
+    T001,
     T003
diff --git a/tests/eventseg/test_event.py b/tests/eventseg/test_event.py
index be6ef345e..dd60134ea 100644
--- a/tests/eventseg/test_event.py
+++ b/tests/eventseg/test_event.py
@@ -74,3 +74,17 @@ def test_weighted_var():
     assert np.allclose(
         es.calc_weighted_event_var(D, weights, mean_pat), true_var),\
         "Failed to compute variance with fractional weights"
+
+
+def test_sym():
+    es = brainiak.eventseg.event.EventSegment(4)
+
+    evpat = np.repeat(np.arange(10).reshape(-1, 1), 4, axis=1)
+    es.set_event_patterns(evpat)
+
+    D = np.repeat(np.arange(10).reshape(1, -1), 20, axis=0)
+    ev = es.find_events(D, var=1)[0]
+
+    # Check that events 1-4 and 2-3 are symmetric
+    assert np.all(np.isclose(ev[:, :2], np.fliplr(np.flipud(ev[:, 2:])))),\
+        "Fit with constant data is not symmetric"

From 36c03d643b5ecaf7fc7ff5c43a97c6c4b1cb59ee Mon Sep 17 00:00:00 2001
From: Christopher Baldassano <chrisb@princeton.edu>
Date: Tue, 20 Feb 2018 09:24:44 -0500
Subject: [PATCH 2/4] Adding news fragment

---
 docs/newsfragments/X.bugfix | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 docs/newsfragments/X.bugfix

diff --git a/docs/newsfragments/X.bugfix b/docs/newsfragments/X.bugfix
new file mode 100644
index 000000000..2ff2c43a5
--- /dev/null
+++ b/docs/newsfragments/X.bugfix
@@ -0,0 +1 @@
+Fixed bug in eventseg that was causing fits to be asymmetric

From 5157fc1f2636681a0e235ba1a41d4bdd213cac1c Mon Sep 17 00:00:00 2001
From: Christopher Baldassano <chrisb@princeton.edu>
Date: Tue, 20 Feb 2018 09:27:31 -0500
Subject: [PATCH 3/4] Updating news fragment title

---
 docs/newsfragments/X.bugfix => 339.bugfix | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename docs/newsfragments/X.bugfix => 339.bugfix (100%)

diff --git a/docs/newsfragments/X.bugfix b/339.bugfix
similarity index 100%
rename from docs/newsfragments/X.bugfix
rename to 339.bugfix

From 4c2c85bcd6f2741517172f4a2003165337ae3eb2 Mon Sep 17 00:00:00 2001
From: Christopher Baldassano <chrisb@princeton.edu>
Date: Tue, 20 Feb 2018 09:27:52 -0500
Subject: [PATCH 4/4] Updating news fragment title

---
 339.bugfix => docs/newsfragments/339.bugfix | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename 339.bugfix => docs/newsfragments/339.bugfix (100%)

diff --git a/339.bugfix b/docs/newsfragments/339.bugfix
similarity index 100%
rename from 339.bugfix
rename to docs/newsfragments/339.bugfix