From cb4ecb1cce0464db3cbd00d91b5d92a66d469488 Mon Sep 17 00:00:00 2001
From: Vadim Markovtsev <gmarkhor@gmail.com>
Date: Thu, 26 Jan 2017 15:18:45 +0100
Subject: [PATCH] Simplify the chain comparisons

Since the body is the same, why not to combine the conditions?
---
 kmc2.pyx | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/kmc2.pyx b/kmc2.pyx
index c361bb0..e1758d0 100644
--- a/kmc2.pyx
+++ b/kmc2.pyx
@@ -107,15 +107,10 @@ def kmc2(X, k, chain_length=200, afkmc2=True, random_state=None, weights=None):
             # Markov chain
             for j in range(q_cand.shape[0]):
                 cand_prob = p_cand[j]/q_cand[j]
-                if j == 0 or curr_prob == 0.0:
-                    # Init new chain
+                if j == 0 or curr_prob == 0.0 or cand_prob/curr_prob > rand_a[j]:
+                    # Init new chain             Metropolis-Hastings step
                     curr_ind = j
                     curr_prob = cand_prob
-                else:
-                    # Metropolis-Hastings step
-                    if cand_prob/curr_prob > rand_a[j]:
-                        curr_ind = j
-                        curr_prob = cand_prob
         rel_row = X[cand_ind[curr_ind], :]
         centers[i+1, :] = rel_row.todense().flatten() if sparse else rel_row
     return centers