implement generic 'smooth' function for all sequence types

1 files changed, 24 insertions, 0 deletions

diff --git a/src/main/scala/scalam/math/package.scala b/src/main/scala/scalam/math/package.scala
new file mode 100644
index 0000000..58063fa
--- /dev/null
+++ b/src/main/scala/scalam/math/package.scala
@@ -0,0 +1,24 @@
+package scalam
+
+import scala.collection.SeqLike
+import scala.collection.generic.CanBuildFrom
+package object math {
+  
+  def smooth[Elem, Coll[Elem]](width: Int, passes: Int, collection: Coll[Elem])(implicit fractional: Fractional[Elem], cbf: CanBuildFrom[Coll[Elem], Elem, Coll[Elem]], view: Coll[Elem] => Seq[Elem]): Coll[Elem] = {
+    def average(xs: Seq[Elem]): Elem = {
+      import fractional._
+      xs.sum / fromInt(xs.length)
+    }
+    
+    def smoothOnce(width: Int, collection: Coll[Elem]) = {
+      val b = cbf(collection)
+      collection.sliding(width).foreach(neighbours => b += average(neighbours))
+      b.result()
+      
+    }
+    
+    if (passes <= 0) collection
+    else smooth(width, passes - 1, smoothOnce(width, collection))
+  }
+  
+}
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