Changeset 1156

Timestamp:

Feb 26, 2008, 9:46:49 AM (16 years ago)

Author:

Markus Ringnér

Message:

Refs. #335, fixed for KNN

Location:

trunk

Files:

• configure.ac (modified) (2 diffs)
• doc/concepts.doxygen (modified) (1 diff)
• yat/classifier/KNN.h (modified) (1 diff)
• yat/classifier/KNN_ReciprocalRank.cc (modified) (2 diffs)
• yat/classifier/KNN_Uniform.cc (modified) (2 diffs)

trunk/configure.ac

@@ -137 +137 @@
   [quiet_nan=no])
 AC_MSG_RESULT($quiet_nan)
+# Check for infinity support for doubles in OS
+# At run-time, but this has the disadvantage that yat cannot be built  
+# for cross-compilation
+AC_MSG_CHECKING([if std::numeric_limits<>::has_infinity is true])
+AC_RUN_IFELSE(
+  [AC_LANG_PROGRAM(
+    [#include <limits>],
+    [return !std::numeric_limits<double>::has_infinity])],
+  [has_infinity=yes],
+  [has_infinity=no])
+AC_MSG_RESULT($has_infinity)
+
 
 # yat specific settings
@@ -182 +194 @@
   Yat will not work on this system!])
 fi
+
+# No support for infinity is fatal -- sub-sequent compilation, or execution
+# of created binary, will fail.
+if test "${has_infinity}" = "no" ; then
+  all_reqs_ok="false"
+  AC_MSG_WARN([
+  Support for infinity required.
+  Yat will not work on this system!])
+fi
+
 
 # Non-existing BLAS is fatal -- sub-sequent compilation will fail.

trunk/doc/concepts.doxygen

@@ -99 +99 @@
 distance. For each class the function calculates a total vote based on
 the the nearest neighbors of the test sample that belong to the
-class. The total vote for each class is stored in the vector \a prediction.
+class. The total vote for each class is stored in the vector \a
+prediction.  The function should be implemented such that nearest
+neighbors with distance infinity do not vote.
 
 \section Implementations

trunk/yat/classifier/KNN.h

@@ -245 +245 @@
         (*distances)(i,j) = distance_(training1.begin(), training1.end(), 
                                       test1.begin());
+        // If the distance is NaN (no common variables with non-zero weights),
+        // the distance is set to infinity to be sorted as a neighbor at the end
+        if(std::isnan((*distances)(i,j))) 
+          (*distances)(i,j)=std::numeric_limits<double>::infinity();
       }
     }

trunk/yat/classifier/KNN_ReciprocalRank.cc

@@ -7 +7 @@
 #include "yat/utility/VectorMutable.h"
 
+#include <cmath>
 #include <vector>
 
@@ -19 +20 @@
   {           
     for(size_t j=0;j<k_sorted.size();j++) 
-      prediction(target(k_sorted[j]))+=1.0/(j+1);               
+      if(!std::isinf(distance(k_sorted[j])))
+         prediction(target(k_sorted[j]))+=1.0/(j+1);                
   }
 

trunk/yat/classifier/KNN_Uniform.cc

@@ -7 +7 @@
 #include "yat/utility/VectorMutable.h"
 
+#include <cmath>
 #include <vector>
 
@@ -19 +20 @@
   {           
     for(size_t j=0;j<k_sorted.size();j++) 
-      prediction(target(k_sorted[j]))+=1.0;           
+      if(!std::isinf(distance(k_sorted[j])))
+         prediction(target(k_sorted[j]))+=1.0;            
   }