[mlpack-svn] r15423 - mlpack/trunk/src/mlpack/methods/rann

[fastlab-svn at coffeetalk-1.cc.gatech.edu]

Author: pram
Date: Fri Jul  5 16:07:32 2013
New Revision: 15423

Log:
Ticket #293 initial fix -- review waiting.

Modified:
   mlpack/trunk/src/mlpack/methods/rann/ra_search_impl.hpp
   mlpack/trunk/src/mlpack/methods/rann/ra_search_rules_impl.hpp

Modified: mlpack/trunk/src/mlpack/methods/rann/ra_search_impl.hpp
==============================================================================
--- mlpack/trunk/src/mlpack/methods/rann/ra_search_impl.hpp	(original)
+++ mlpack/trunk/src/mlpack/methods/rann/ra_search_impl.hpp	Fri Jul  5 16:07:32 2013
@@ -153,6 +153,21 @@
        const bool firstLeafExact,
        const size_t singleSampleLimit)
 {
+  // Sanity check to make sure that the rank-approximation is 
+  // greater than the number of neighbors requested.
+
+  // The rank approximation
+  size_t t = (size_t) std::ceil(tau * (double) referenceSet.n_cols  
+                                / 100.0);
+  if (t <= k)
+  {
+    Log::Warn << tau << "-rank-approximation => " << k << 
+      " neighbors requested from the top " << t <<
+      "." << std::endl;
+    Log::Fatal << "No approximation here, " <<
+      "hence quitting...please increase 'tau' and try again." << std::endl;
+  }
+
   Timer::Start("computing_neighbors");
 
   // If we have built the trees ourselves, then we will have to map all the

Modified: mlpack/trunk/src/mlpack/methods/rann/ra_search_rules_impl.hpp
==============================================================================
--- mlpack/trunk/src/mlpack/methods/rann/ra_search_rules_impl.hpp	(original)
+++ mlpack/trunk/src/mlpack/methods/rann/ra_search_rules_impl.hpp	Fri Jul  5 16:07:32 2013
@@ -97,6 +97,18 @@
   // The rank approximation
   size_t t = (size_t) std::ceil(tau * (double) n / 100.0);
 
+  // Sanity check here (if the previous one is somehow missed)
+  // to make sure that the rank-approximation is actually
+  // giving some approximation.
+  if (t <= k)
+  {
+    Log::Warn << tau << "-rank-approximation => " << k << 
+      " neighbors requested from the top " << t <<
+      "." << std::endl;
+    Log::Fatal << "No approximation here, " <<
+      "hence quitting...please increase 'tau' and try again." << std::endl;
+  }
+
   double prob;
   Log::Assert(alpha <= 1.0);
 
@@ -143,7 +155,7 @@
 
   } while (!done);
 
-  return (m + 1);
+  return (std::min(m + 1, n));
 }
 
 
@@ -169,7 +181,7 @@
     if (m < k)
       return 0.0;
 
-    if (m > n - t + k)
+    if (m > n - t + k - 1)
       return 1.0;
 
     double eps = (double) t / (double) n;