From 21b8ed158b4f09ecd9205e1a541189f5c490f82a Mon Sep 17 00:00:00 2001
From: vsuthichai <VictorSuthichai@eharmony.com>
Date: Thu, 18 Aug 2016 15:25:47 -0700
Subject: [PATCH] Combinations #23 Subsets #25

---
 .../optimizer/hyperparam/Combinations.scala   | 12 ++++------
 .../spotz/optimizer/hyperparam/Subsets.scala  | 23 +++++++++++++++----
 .../spotz/examples/vw/VwHoldout.scala         |  2 +-
 3 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/core/src/main/scala/com/eharmony/spotz/optimizer/hyperparam/Combinations.scala b/core/src/main/scala/com/eharmony/spotz/optimizer/hyperparam/Combinations.scala
index e5c5681..9fa4cad 100644
--- a/core/src/main/scala/com/eharmony/spotz/optimizer/hyperparam/Combinations.scala
+++ b/core/src/main/scala/com/eharmony/spotz/optimizer/hyperparam/Combinations.scala
@@ -17,24 +17,20 @@ abstract class AbstractCombinations[T](
 
   protected val values = iterable.toSeq
 
-  assert(k > 0, "k must be greater than 0")
-  assert(k <= values.length, s"k must be less than or equal to length of the iterable, ${values.length}")
-
   def sample(rng: Random): Iterable[T] = {
     if (replacement) sampleWithReplacement(rng)
     else sampleNoReplacement(rng)
   }
 
   def sampleWithReplacement(rng: Random) = {
-    val combo = mutable.SortedSet[T]()
+    val combo = new mutable.PriorityQueue[T]()
 
     while (combo.size < k) {
       val index = rng.nextInt(values.length)
-      val element = values(rng.nextInt(values.length))
-      combo.add(element)
+      combo += values(index)
     }
 
-    combo.toSeq
+    combo.toIndexedSeq
   }
 
   def sampleNoReplacement(rng: Random) = {
@@ -49,7 +45,7 @@ abstract class AbstractCombinations[T](
       }
     }
 
-    combo.toSeq
+    combo.toIndexedSeq
   }
 }
 
diff --git a/core/src/main/scala/com/eharmony/spotz/optimizer/hyperparam/Subsets.scala b/core/src/main/scala/com/eharmony/spotz/optimizer/hyperparam/Subsets.scala
index c551166..cbbc7eb 100644
--- a/core/src/main/scala/com/eharmony/spotz/optimizer/hyperparam/Subsets.scala
+++ b/core/src/main/scala/com/eharmony/spotz/optimizer/hyperparam/Subsets.scala
@@ -14,7 +14,19 @@ import scala.util.Random
 abstract class AbstractSubset[T](iterable: Iterable[T], k: Int, replacement: Boolean = false)(implicit ord: Ordering[T]) extends Serializable {
   protected val values = iterable.toIndexedSeq
 
-  def sample(rng: Random): Iterable[T] = {
+  def sampleWithReplacement(rng: Random): Iterable[T] = {
+    val sampleSize = rng.nextInt(k) + 1
+    val subset = new mutable.PriorityQueue[T]()
+
+    while (subset.size < k) {
+      val index = rng.nextInt(values.length)
+      subset += values(index)
+    }
+
+    subset.toIndexedSeq
+  }
+
+  def sampleNoReplacement(rng: Random): Iterable[T] = {
     val sampleSize = rng.nextInt(k) + 1
     val subset = mutable.SortedSet[T]()
     val indices = mutable.Set[Int]()
@@ -22,9 +34,7 @@ abstract class AbstractSubset[T](iterable: Iterable[T], k: Int, replacement: Boo
     while (subset.size < sampleSize) {
       val index = rng.nextInt(values.size)
 
-      if (replacement) {
-        subset.add(values(index))
-      } else if (!indices.contains(index)) {
+      if (!indices.contains(index)) {
         indices.add(index)
         subset.add(values(index))
       }
@@ -32,6 +42,11 @@ abstract class AbstractSubset[T](iterable: Iterable[T], k: Int, replacement: Boo
 
     subset.toIndexedSeq
   }
+
+  def sample(rng: Random): Iterable[T] = {
+    if (replacement) sampleWithReplacement(rng)
+    else sampleNoReplacement(rng)
+  }
 }
 
 /**
diff --git a/examples/src/main/scala/com/eharmony/spotz/examples/vw/VwHoldout.scala b/examples/src/main/scala/com/eharmony/spotz/examples/vw/VwHoldout.scala
index 2646e31..c6ffcb4 100644
--- a/examples/src/main/scala/com/eharmony/spotz/examples/vw/VwHoldout.scala
+++ b/examples/src/main/scala/com/eharmony/spotz/examples/vw/VwHoldout.scala
@@ -41,7 +41,7 @@ trait VwHoldout extends AbstractVwHoldout {
 trait VwHoldoutRandomSearch extends VwHoldout {
   val space = Map(
     ("l", UniformDouble(0, 1)),
-    ("q", Combinations(List("a", "b", "c", "d"), k = 2, x = 2))
+    ("interactions", Combinations('a' to 'z', k = 4, x = 7))
   )
 
   def main(args: Array[String]) {