[systemds] branch master updated: [MINOR] minor fixes in smote

[ssiddiqi]

This is an automated email from the ASF dual-hosted git repository.

ssiddiqi pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/systemds.git


The following commit(s) were added to refs/heads/master by this push:
     new 8501fb3  [MINOR] minor fixes in smote
8501fb3 is described below

commit 8501fb325309249e6b4414aa468f69b1a2539153
Author: Shafaq Siddiqi <shafaq.sidd...@tugraz.at>
AuthorDate: Mon Oct 5 14:06:40 2020 +0200

    [MINOR] minor fixes in smote
    
    replace the rbind/cbind with indexing
    rand call is updated with a seed value
---
 scripts/builtin/smote.dml                          | 37 +++++++++++++++-------
 .../test/functions/builtin/BuiltinSmoteTest.java   |  7 +++-
 2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/scripts/builtin/smote.dml b/scripts/builtin/smote.dml
index 857120e..8e04e1d 100644
--- a/scripts/builtin/smote.dml
+++ b/scripts/builtin/smote.dml
@@ -46,41 +46,54 @@ return (Matrix[Double] Y) {
     print("the number of samples should be an integral multiple of 100. 
Setting s = 100")
     s = 100
   }
+  
+  if(k < 1) {
+    print("k should not be less than 1. Setting k value to default k = 1.")
+    k = 1
+  }
+  
   # matrix to keep the index of KNN for each minority sample
-  knn_index = matrix(0,k,0)
+  knn_index = matrix(0,k,nrow(X))
   # find nearest neighbour
   for(i in 1:nrow(X))
   {
     knn = nn(X, X[i, ], k)
-    knn_index = cbind(knn_index, knn)
+    knn_index[, i] = knn
   }
   
   # number of synthetic samples from each minority class sample
-  iter = (s/100)
+  iter = 0
+  iterLim = (s/100)
   # matrix to store synthetic samples
-  synthetic_samples = matrix(0, 0, ncol(X))
-  while(iter > 0)
+  synthetic_samples = matrix(0, iterLim*ncol(knn_index), ncol(X))
+  
+  # shuffle the nn indexes
+  if(k < iterLim)
+    rand_index = sample(k, iterLim, TRUE)
+  else 
+    rand_index = sample(k, iterLim)
+  
+  while(iter < iterLim)
   {
-    # generate a random number
-    # TODO avoid duplicate random numbers
-    rand_index = as.integer(as.scalar(Rand(rows=1, cols=1, min=1, max=k)))
     # pick the random NN
-    knn_sample = knn_index[rand_index,] 
+    knn_sample = knn_index[as.scalar(rand_index[iter+1]),] 
     # generate sample    
     for(i in 1:ncol(knn_index))
     {
       index = as.scalar(knn_sample[1,i])
       X_diff = X[index,] - X[i, ]
-      gap = as.scalar(Rand(rows=1, cols=1, min=0, max=1))
+      gap = as.scalar(Rand(rows=1, cols=1, min=0, max=1, seed = 41))
       X_sys = X[i, ] + (gap*X_diff)
-      synthetic_samples = rbind(synthetic_samples, X_sys)
+      synthetic_samples[iter*ncol(knn_index)+i,] = X_sys;
     }
-    iter = iter - 1
+    iter = iter + 1
   }
 
   Y = synthetic_samples
+  
   if(verbose)
     print(nrow(Y)+ " synthesized samples generated.")
+
 }
   
 
diff --git 
a/src/test/java/org/apache/sysds/test/functions/builtin/BuiltinSmoteTest.java 
b/src/test/java/org/apache/sysds/test/functions/builtin/BuiltinSmoteTest.java
index 675e741..4eb2fdf 100644
--- 
a/src/test/java/org/apache/sysds/test/functions/builtin/BuiltinSmoteTest.java
+++ 
b/src/test/java/org/apache/sysds/test/functions/builtin/BuiltinSmoteTest.java
@@ -48,8 +48,13 @@ public class BuiltinSmoteTest extends AutomatedTestBase {
        }
 
        @Test
+       public void testSmote0CP() {
+               runSmoteTest(100, 1, LopProperties.ExecType.CP);
+       }
+
+       @Test
        public void testSmote1CP() {
-               runSmoteTest(300, 3, LopProperties.ExecType.CP);
+               runSmoteTest(300, 10, LopProperties.ExecType.CP);
        }
 
        @Test