diff --git a/src/main/scala/scim/datastruct/Configuration.scala b/src/main/scala/scim/datastruct/Configuration.scala
index aec98fd..fc7d72e 100644
--- a/src/main/scala/scim/datastruct/Configuration.scala
+++ b/src/main/scala/scim/datastruct/Configuration.scala
@@ -10,10 +10,15 @@ import scala.collection.parallel.ForkJoinTaskSupport
 
 // Note: case classes implement equality and compare their values and not the memory address
 // It only compares vals from the constructor
-case class Time(time: Int, duration: Int){
+case class Time(time: Int, duration: Int) extends Ordered[Time]{
   def prev: Time = { Time(time - 1, duration) }
   def start: Boolean = { time == 0 }
   def get: Int = { time }
+
+  override def compare(that: Time): Int = {
+    time.compare(that.time)
+  }
+
 }
 
 // while it would seem convinient to just throw the sensors/behaviours as value into these
@@ -23,6 +28,10 @@ case class SharedMemory(sensor: Map[Time, Map[Cell, Map[Group, Vector[SensorResu
                         groundTruth: Map[Time, Map[Cell, Map[Group, Truth]]],
                         config: SimulationConfig,
                         output: Vector[BroadcastObject[Boolean]]) {
+  // memory optimization: remove sensor and throw output into output
+  // only map Truths from config into groundtruth, do a if groundTruth.contains(time) groundTruth(time) else prevTruth in case of time.start Truth(None) (or better map it to time.start anyways in parser)
+  // can drop cell from ground truth
+
   // This could be spatially optimized to have a function to invoke a new simulation tick
   // a template of Map[Cell, Map[Group, Vector[SensorResult]]] would have to be kept and deep copied when
   // another tick is simulated. this won't work for ground truth, as it may already be defined
@@ -77,13 +86,28 @@ case class SimulationConfig(duration: Int, runs: Int, tickfactor: Int = 1,
   val sensorThreadPool: ForkJoinTaskSupport = new ForkJoinTaskSupport(new scala.concurrent.forkjoin.ForkJoinPool(parSensorThreads))
 }
 case class SensorResult(result: BroadcastObject[(Group, Cell, Option[Double])]) extends BroadcastHandler(result)
+/* rough size estimation
+  Group(name: String, sensorParent: Option[String] = None)
+  String: 2*x, String: 2*x
+  case class Cell(x: Int, y: Int)
+  Int: 4, Int: 4
+  Double: 8
+  4*8+4+4+8 ~ 64
+  SensorResult(result: BroadcastObject[(Group, Cell, Option[Double])])
+  default: 64
+  value: 64
+  locks: 8*4 (at least) = 32 (probably 64)
+  frame: 4
+  bool: 1
+  ~ 3*64 = 192 byte
+ */
 case class SensorID(group: Group, Id: Int)
 case class Duration(simDuration: Int)
 case class TickFactor(factor: Int) // processed when parsing configuration, artifically place timings
 case class Cell(x: Int, y: Int)
 case class Group(name: String, sensorParent: Option[String] = None){
   // the sensorParent serves as indicator for the parser that a ground truth is not required
-  // FIXME: use parent as get function and parent.set as setter to make var private
+  // TODO: use parent as get function and parent.set as setter to make var private
   var parent: Option[String]  = sensorParent // have to make this mutable to reassign it during parsing
   def getParentOrGroup: Group = {
     if(parent.isEmpty) {
diff --git a/src/main/scala/scim/lib/Library.scala b/src/main/scala/scim/lib/Library.scala
index 79f6cb3..2a1c359 100644
--- a/src/main/scala/scim/lib/Library.scala
+++ b/src/main/scala/scim/lib/Library.scala
@@ -3,11 +3,14 @@ package scim.lib
 // java imports
 import java.io.{File, FileInputStream}
 
+import scala.collection.immutable.ListMap
+
+
 
 // scala imports
+import scala.collection.JavaConverters._
 import scala.collection.convert.wrapAll._
 import scala.collection.mutable
-import scala.collection.JavaConverters._
 
 // external imports
 import org.yaml.snakeyaml.Yaml
@@ -45,6 +48,7 @@ package object printUtil {
 }
 
 package object evalUtil {
+
   def time[A](name: String, f: => A): A = {
     val t0 = System.nanoTime()
     val result = f
@@ -52,6 +56,14 @@ package object evalUtil {
     println(name + " Elapsed time: " + (t1 - t0) + "ns")
     result
   }
+
+  // FIXME: obviously need to assign something and not null
+  def memSize(obj: Any): Long = {
+//    import java.lang.instrument.Instrumentation
+//    val instrumentation: Instrumentation = null
+//    instrumentation.getObjectSize(obj)
+    0
+  }
 }
 
 package object debugUtil {
@@ -144,6 +156,59 @@ package object mapUtil {
     }
   }
 
+  def getFirstElement[A, B](map: Map[A, B])(implicit ordering:Ordering[A]): (A, B) = {
+    ListMap(map.toSeq.sortBy(_._1):_*).toVector(0)
+  }
+
+  def getLastElement[A, B](map: Map[A, B])(implicit ordering:Ordering[A]): (A, B) = {
+    ListMap(map.toSeq.sortBy(_._1):_*).toVector(map.size - 1)
+  }
+
+  // this is just a binary search that returns the closest match
+  private def getClosestKeysHelper[A, B](key: A, start: Int, end: Int, vector: Vector[(A, B)])(implicit ordering:Ordering[A]): ((A, B), Option[(A, B)]) = {
+    val mid = start + (end - start) / 2
+    val foundKey = vector(mid)._1
+    // dont check for equality but order
+    if(ordering.compare(key, foundKey) == 0) return (vector(mid), Some(vector(mid + 1)))
+    // special case for 2 elements left
+    if((end - start) == 1) {
+      if(ordering.compare(key, vector(end)._1) >= 0) {
+        (vector(end), None)
+      } else {
+        // use getFirstElement to check if this is the beginning
+        (vector(start), Some(vector(end)))
+      }
+    } else {
+      if (ordering.compare(key, foundKey) > 0) {
+        getClosestKeysHelper(key, mid, end, vector)
+      } else {
+        getClosestKeysHelper(key, start, mid, vector)
+      }
+    }
+  }
+
+  def getClosestKeys[A, B](key: A, map: Map[A, B])(implicit ordering:Ordering[A]): ((A, B), Option[(A, B)]) = {
+    val vectorMap = ListMap(map.toSeq.sortBy(_._1):_*).toVector
+    getClosestKeysHelper(key, 0, vectorMap.size - 1, vectorMap)
+  }
+
+  def getKeyOrNext[A, B](key: A, map: Map[A, B])(implicit ordering:Ordering[A]): (A, B) = {
+    if(map.contains(key)) return (key, map(key))
+    val vectorMap = ListMap(map.toSeq.sortBy(_._1):_*).toVector
+    val result = getClosestKeysHelper(key, 0, vectorMap.size - 1, vectorMap)
+    if(ordering.compare(key, result._1._1)<= 0) {
+      result._1
+    } else {
+      result._2.getOrElse(result._1)
+    }
+  }
+
+  def getKeyOrPrev[A, B](key: A, map: Map[A, B])(implicit ordering:Ordering[A]): (A, B) = {
+    if(map.contains(key)) return (key, map(key))
+    val vectorMap = ListMap(map.toSeq.sortBy(_._1):_*).toVector
+    val result = getClosestKeysHelper(key, 0, vectorMap.size - 1, vectorMap)
+    result._1
+  }
 }
 
 package object yml {