Merge branch 'issue-258' into 'master'

Add "Initial Guess" Search Strategy

Closes #258

See merge request !210

theodolite/src/main/kotlin/theodolite/strategies/searchstrategy/GuessStrategy.kt

+package theodolite.strategies.searchstrategy
+
+import io.quarkus.runtime.annotations.RegisterForReflection
+import theodolite.util.Resource
+
+/**
+ * Base class for the implementation of Guess strategies. Guess strategies are strategies to determine the resource
+ * demand we start with in our initial guess search strategy.
+ */
+
+@RegisterForReflection
+abstract class GuessStrategy {
+    /**
+     * Computing the resource demand for the initial guess search strategy to start with.
+     *
+     * @param resources List of all possible [Resource]s.
+     * @param lastLowestResource Previous resource demand needed for the given load.
+     *
+     * @return Returns the resource demand to start the initial guess search strategy with or null
+     */
+    abstract fun firstGuess(resources: List<Resource>, lastLowestResource: Resource?): Resource?
+}
\ No newline at end of file

theodolite/src/main/kotlin/theodolite/strategies/searchstrategy/InitialGuessSearchStrategy.kt

+package theodolite.strategies.searchstrategy
+
+import mu.KotlinLogging
+import theodolite.execution.BenchmarkExecutor
+import theodolite.util.LoadDimension
+import theodolite.util.Resource
+import theodolite.util.Results
+
+private val logger = KotlinLogging.logger {}
+
+/**
+ *  Search strategy implementation for determining the smallest suitable resource demand.
+ *  Starting with a resource amount provided by a guess strategy.
+ *
+ * @param benchmarkExecutor Benchmark executor which runs the individual benchmarks.
+ * @param guessStrategy Strategy that provides us with a guess for the first resource amount.
+ * @param results current results of all previously performed benchmarks.
+ */
+class InitialGuessSearchStrategy(benchmarkExecutor: BenchmarkExecutor, guessStrategy: GuessStrategy, results: Results) :
+        SearchStrategy(benchmarkExecutor, guessStrategy, results) {
+
+    override fun findSuitableResource(load: LoadDimension, resources: List<Resource>): Resource? {
+
+        if(resources.isEmpty()) {
+            logger.info { "You need to specify resources to be checked for the InitialGuessSearchStrategy to work." }
+            return null
+        }
+
+        if(guessStrategy == null){
+            logger.info { "Your InitialGuessSearchStrategy doesn't have a GuessStrategy. This is not supported." }
+            return null
+        }
+
+        if(results == null){
+            logger.info { "The results need to be initialized." }
+            return null
+        }
+
+
+        var lastLowestResource : Resource? = null
+
+        // Getting the lastLowestResource from results and calling firstGuess() with it
+        if (!results.isEmpty()) {
+            val maxLoad: LoadDimension? = this.results.getMaxBenchmarkedLoad(load)
+            lastLowestResource = this.results.getMinRequiredInstances(maxLoad)
+            if (lastLowestResource.get() == Int.MAX_VALUE) lastLowestResource = null
+        }
+        lastLowestResource = this.guessStrategy.firstGuess(resources, lastLowestResource)
+
+        if (lastLowestResource != null) {
+            val resourcesToCheck: List<Resource>
+            val startIndex: Int = resources.indexOf(lastLowestResource)
+
+            logger.info { "Running experiment with load '${load.get()}' and resources '${lastLowestResource.get()}'" }
+
+            // If the first experiment passes, starting downward linear search
+            // otherwise starting upward linear search
+            if (this.benchmarkExecutor.runExperiment(load, lastLowestResource)) {
+
+                resourcesToCheck = resources.subList(0, startIndex).reversed()
+                if (resourcesToCheck.isEmpty()) return lastLowestResource
+
+                var currentMin: Resource = lastLowestResource
+                for (res in resourcesToCheck) {
+
+                    logger.info { "Running experiment with load '${load.get()}' and resources '${res.get()}'" }
+                    if (this.benchmarkExecutor.runExperiment(load, res)) {
+                        currentMin = res
+                    }
+                }
+                return currentMin
+            }
+            else {
+                if (resources.size <= startIndex + 1) {
+                    logger.info{ "No more resources left to check." }
+                    return null
+                }
+                resourcesToCheck = resources.subList(startIndex + 1, resources.size)
+
+                for (res in resourcesToCheck) {
+
+                    logger.info { "Running experiment with load '${load.get()}' and resources '${res.get()}'" }
+                    if (this.benchmarkExecutor.runExperiment(load, res)) return res
+                }
+            }
+        }
+        else {
+            logger.info { "InitialGuessSearchStrategy called without lastLowestResource value, which is needed as a " +
+                    "starting point!" }
+        }
+        return null
+    }
+}
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theodolite/src/main/kotlin/theodolite/strategies/searchstrategy/PrevResourceMinGuess.kt

+package theodolite.strategies.searchstrategy
+
+import theodolite.util.Resource
+
+/**
+ * This Guess strategy takes the minimal resource demand of the previous load, which is given as an argument for the
+ * firstGuess function.
+ */
+
+class PrevResourceMinGuess() : GuessStrategy(){
+
+    /**
+     * @param resources List of all possible [Resource]s.
+     * @param lastLowestResource Previous resource demand needed for the given load.
+     *
+     * @return the value of lastLowestResource if given otherwise the first element of the resource list or null
+     */
+    override fun firstGuess(resources: List<Resource>, lastLowestResource: Resource?): Resource? {
+
+        if (lastLowestResource != null) return lastLowestResource
+        else if(resources.isNotEmpty()) return resources[0]
+        else return null
+    }
+}
\ No newline at end of file

theodolite/src/main/kotlin/theodolite/strategies/searchstrategy/SearchStrategy.kt

@@ -4,14 +4,18 @@ import io.quarkus.runtime.annotations.RegisterForReflection
 import theodolite.execution.BenchmarkExecutor
 import theodolite.util.LoadDimension
 import theodolite.util.Resource
+import theodolite.util.Results
 
 /**
  *  Base class for the implementation for SearchStrategies. SearchStrategies determine the smallest suitable number of instances.
  *
  * @param benchmarkExecutor Benchmark executor which runs the individual benchmarks.
+ * @param guessStrategy Guess strategy for the initial resource amount in case the InitialGuessStrategy is selected.
+ * @param results the [Results] object.
  */
 @RegisterForReflection
-abstract class SearchStrategy(val benchmarkExecutor: BenchmarkExecutor) {
+abstract class SearchStrategy(val benchmarkExecutor: BenchmarkExecutor, val guessStrategy: GuessStrategy? = null,
+                              val results: Results? = null) {
     /**
      * Find smallest suitable resource from the specified resource list for the given load.
      *

theodolite/src/main/kotlin/theodolite/util/Results.kt

@@ -3,7 +3,7 @@ package theodolite.util
 import io.quarkus.runtime.annotations.RegisterForReflection
 
 /**
- * Central class that saves the state of a execution of Theodolite. For an execution, it is used to save the result of
+ * Central class that saves the state of an execution of Theodolite. For an execution, it is used to save the result of
  * individual experiments. Further, it is used by the RestrictionStrategy to
  * perform the [theodolite.strategies.restriction.RestrictionStrategy].
  */
@@ -44,16 +44,16 @@ class Results {
      * If no experiments have been marked as either successful or unsuccessful
      * yet, a Resource with the constant value Int.MIN_VALUE is returned.
      */
-    fun getMinRequiredInstances(load: LoadDimension?): Resource? {
+    fun getMinRequiredInstances(load: LoadDimension?): Resource {
         if (this.results.isEmpty()) {
             return Resource(Int.MIN_VALUE, emptyList())
         }
 
-        var minRequiredInstances: Resource? = Resource(Int.MAX_VALUE, emptyList())
+        var minRequiredInstances = Resource(Int.MAX_VALUE, emptyList())
         for (experiment in results) {
             // Get all successful experiments for requested load
             if (experiment.key.first == load && experiment.value) {
-                if (minRequiredInstances == null || experiment.key.second.get() < minRequiredInstances.get()) {
+                if (experiment.key.second.get() < minRequiredInstances.get()) {
                     // Found new smallest resources
                     minRequiredInstances = experiment.key.second
                 }
@@ -83,4 +83,13 @@ class Results {
         }
         return maxBenchmarkedLoad
     }
+
+    /**
+     * Checks whether the results are empty.
+     *
+     * @return true if [results] is empty.
+     */
+    fun isEmpty(): Boolean{
+        return results.isEmpty()
+    }
 }

theodolite/src/test/kotlin/theodolite/InitialGuessSearchStrategyTest.kt

+package theodolite
+
+import io.quarkus.test.junit.QuarkusTest
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import theodolite.benchmark.BenchmarkExecution
+import theodolite.strategies.searchstrategy.InitialGuessSearchStrategy
+import theodolite.util.LoadDimension
+import theodolite.util.Resource
+import theodolite.util.Results
+import mu.KotlinLogging
+import theodolite.strategies.searchstrategy.PrevResourceMinGuess
+
+private val logger = KotlinLogging.logger {}
+
+@QuarkusTest
+class InitialGuessSearchStrategyTest {
+
+    @Test
+    fun testInitialGuessSearch() {
+        val mockResults = arrayOf(
+            arrayOf(true, true, true, true, true, true, true),
+            arrayOf(false, false, true, true, true, true, true),
+            arrayOf(false, false, true, true, true, true, true),
+            arrayOf(false, false, false, true, true, true, true),
+            arrayOf(false, false, false, false, true, true, true),
+            arrayOf(false, false, false, false, false, false, true),
+            arrayOf(false, false, false, false, false, false, false)
+        )
+        val mockLoads: List<LoadDimension> = (0..6).map { number -> LoadDimension(number, emptyList()) }
+        val mockResources: List<Resource> = (0..6).map { number -> Resource(number, emptyList()) }
+        val results = Results()
+        val benchmark = TestBenchmark()
+        val guessStrategy = PrevResourceMinGuess()
+        val sloChecker: BenchmarkExecution.Slo = BenchmarkExecution.Slo()
+        val benchmarkExecutor = TestBenchmarkExecutorImpl(mockResults, benchmark, results, listOf(sloChecker), 0, 0, 5)
+        val strategy = InitialGuessSearchStrategy(benchmarkExecutor,guessStrategy, results)
+
+        val actual: ArrayList<Resource?> = ArrayList()
+        val expected: ArrayList<Resource?> = ArrayList(listOf(0, 2, 2, 3, 4, 6).map { x -> Resource(x, emptyList()) })
+        expected.add(null)
+
+        for (load in mockLoads) {
+            val returnVal : Resource? = strategy.findSuitableResource(load, mockResources)
+            if(returnVal != null) {
+                logger.info { "returnVal '${returnVal.get()}'" }
+            }
+            else {
+                logger.info { "returnVal is null." }
+            }
+            actual.add(returnVal)
+        }
+
+        assertEquals(actual, expected)
+    }
+
+    @Test
+    fun testInitialGuessSearchLowerResourceDemandHigherLoad() {
+        val mockResults = arrayOf(
+            arrayOf(true, true, true, true, true, true, true),
+            arrayOf(false, false, true, true, true, true, true),
+            arrayOf(false, false, true, true, true, true, true),
+            arrayOf(false, true, true, true, true, true, true),
+            arrayOf(false, false, false, false, true, true, true),
+            arrayOf(false, false, false, false, false, false, true),
+            arrayOf(false, false, false, false, false, false, false)
+        )
+        val mockLoads: List<LoadDimension> = (0..6).map { number -> LoadDimension(number, emptyList()) }
+        val mockResources: List<Resource> = (0..6).map { number -> Resource(number, emptyList()) }
+        val results = Results()
+        val benchmark = TestBenchmark()
+        val guessStrategy = PrevResourceMinGuess()
+        val sloChecker: BenchmarkExecution.Slo = BenchmarkExecution.Slo()
+        val benchmarkExecutor = TestBenchmarkExecutorImpl(mockResults, benchmark, results, listOf(sloChecker), 0, 0, 5)
+        val strategy = InitialGuessSearchStrategy(benchmarkExecutor,guessStrategy, results)
+
+        val actual: ArrayList<Resource?> = ArrayList()
+        val expected: ArrayList<Resource?> = ArrayList(listOf(0, 2, 2, 1, 4, 6).map { x -> Resource(x, emptyList()) })
+        expected.add(null)
+
+        for (load in mockLoads) {
+            val returnVal : Resource? = strategy.findSuitableResource(load, mockResources)
+            if(returnVal != null) {
+                logger.info { "returnVal '${returnVal.get()}'" }
+            }
+            else {
+                logger.info { "returnVal is null." }
+            }
+            actual.add(returnVal)
+        }
+
+        assertEquals(actual, expected)
+    }
+
+    @Test
+    fun testInitialGuessSearchFirstNotDoable() {
+        val mockResults = arrayOf(
+                arrayOf(false, false, false, false, false, false, false),
+                arrayOf(false, false, true, true, true, true, true),
+                arrayOf(false, false, false, true, true, true, true),
+                arrayOf(true, true, true, true, true, true, true),
+                arrayOf(false, false, false, false, true, true, true),
+                arrayOf(false, false, false, false, false, false, true),
+                arrayOf(false, false, false, false, false, false, false)
+        )
+        val mockLoads: List<LoadDimension> = (0..6).map { number -> LoadDimension(number, emptyList()) }
+        val mockResources: List<Resource> = (0..6).map { number -> Resource(number, emptyList()) }
+        val results = Results()
+        val benchmark = TestBenchmark()
+        val guessStrategy = PrevResourceMinGuess()
+        val sloChecker: BenchmarkExecution.Slo = BenchmarkExecution.Slo()
+        val benchmarkExecutor = TestBenchmarkExecutorImpl(mockResults, benchmark, results, listOf(sloChecker), 0, 0, 5)
+        val strategy = InitialGuessSearchStrategy(benchmarkExecutor, guessStrategy, results)
+
+        val actual: ArrayList<Resource?> = ArrayList()
+        var expected: ArrayList<Resource?> = ArrayList(listOf(2, 3, 0, 4, 6).map { x -> Resource(x, emptyList()) })
+        expected.add(null)
+        expected = ArrayList(listOf(null) + expected)
+
+        for (load in mockLoads) {
+            val returnVal : Resource? = strategy.findSuitableResource(load, mockResources)
+            if(returnVal != null) {
+                logger.info { "returnVal '${returnVal.get()}'" }
+            }
+            else {
+                logger.info { "returnVal is null." }
+            }
+            actual.add(returnVal)
+        }
+
+        assertEquals(actual, expected)
+    }
+}
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