merge: Extract scheduler from simulation coroutine dispatcher (#106)

This pull request extracts the scheduler from the `SimulationCoroutineDispatcher` into 
a separate `SimulationScheduler` class which allows users to re-use the scheduler 
between different coroutine dispatchers.

We implement the `SimulationScheduler` in Java, removing the explicit dependency on 
Kotlin or `kotlinx-coroutines`. The scheduler uses a separate specialized priority queue 
implementation that eliminates allocation in the hot path of the simulator.

## Implementation Notes :hammer_and_pick:

* Add Java-based simulator core
* Use SimulationScheduler in coroutine dispatcher
* Rename runBlockingSimulation to runSimulation

## External Dependencies :four_leaf_clover:

* N/A 

## Breaking API Changes :warning:

* The Kotlin API for simulation has been moved to `org.opendc.simulator.kotlin`.
* `runBlockingSImulation` renamed to `runSimulation`

7 files changed, 52 insertions, 52 deletions

diff --git a/opendc-simulator/opendc-simulator-flow/src/jmh/kotlin/org/opendc/simulator/flow/FlowBenchmarks.kt b/opendc-simulator/opendc-simulator-flow/src/jmh/kotlin/org/opendc/simulator/flow/FlowBenchmarks.kt
index aabd2220..86fbe8e4 100644
--- a/opendc-simulator/opendc-simulator-flow/src/jmh/kotlin/org/opendc/simulator/flow/FlowBenchmarks.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/jmh/kotlin/org/opendc/simulator/flow/FlowBenchmarks.kt
@@ -24,10 +24,10 @@ package org.opendc.simulator.flow
 
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.launch
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.mux.ForwardingFlowMultiplexer
 import org.opendc.simulator.flow.mux.MaxMinFlowMultiplexer
 import org.opendc.simulator.flow.source.TraceFlowSource
+import org.opendc.simulator.kotlin.runSimulation
 import org.openjdk.jmh.annotations.*
 import java.util.concurrent.ThreadLocalRandom
 import java.util.concurrent.TimeUnit
@@ -49,27 +49,27 @@ class FlowBenchmarks {
 
     @Benchmark
     fun benchmarkSink() {
-        return runBlockingSimulation {
+        return runSimulation {
             val engine = FlowEngine(coroutineContext, clock)
             val provider = FlowSink(engine, 4200.0)
-            return@runBlockingSimulation provider.consume(TraceFlowSource(trace))
+            return@runSimulation provider.consume(TraceFlowSource(trace))
         }
     }
 
     @Benchmark
     fun benchmarkForward() {
-        return runBlockingSimulation {
+        return runSimulation {
             val engine = FlowEngine(coroutineContext, clock)
             val provider = FlowSink(engine, 4200.0)
             val forwarder = FlowForwarder(engine)
             provider.startConsumer(forwarder)
-            return@runBlockingSimulation forwarder.consume(TraceFlowSource(trace))
+            return@runSimulation forwarder.consume(TraceFlowSource(trace))
         }
     }
 
     @Benchmark
     fun benchmarkMuxMaxMinSingleSource() {
-        return runBlockingSimulation {
+        return runSimulation {
             val engine = FlowEngine(coroutineContext, clock)
             val switch = MaxMinFlowMultiplexer(engine)
 
@@ -77,13 +77,13 @@ class FlowBenchmarks {
             FlowSink(engine, 3000.0).startConsumer(switch.newOutput())
 
             val provider = switch.newInput()
-            return@runBlockingSimulation provider.consume(TraceFlowSource(trace))
+            return@runSimulation provider.consume(TraceFlowSource(trace))
         }
     }
 
     @Benchmark
     fun benchmarkMuxMaxMinTripleSource() {
-        return runBlockingSimulation {
+        return runSimulation {
             val engine = FlowEngine(coroutineContext, clock)
             val switch = MaxMinFlowMultiplexer(engine)
 
@@ -101,7 +101,7 @@ class FlowBenchmarks {
 
     @Benchmark
     fun benchmarkMuxExclusiveSingleSource() {
-        return runBlockingSimulation {
+        return runSimulation {
             val engine = FlowEngine(coroutineContext, clock)
             val switch = ForwardingFlowMultiplexer(engine)
 
@@ -109,13 +109,13 @@ class FlowBenchmarks {
             FlowSink(engine, 3000.0).startConsumer(switch.newOutput())
 
             val provider = switch.newInput()
-            return@runBlockingSimulation provider.consume(TraceFlowSource(trace))
+            return@runSimulation provider.consume(TraceFlowSource(trace))
         }
     }
 
     @Benchmark
     fun benchmarkMuxExclusiveTripleSource() {
-        return runBlockingSimulation {
+        return runSimulation {
             val engine = FlowEngine(coroutineContext, clock)
             val switch = ForwardingFlowMultiplexer(engine)
 
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
index e7b25554..d782d036 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowConsumerContextTest.kt
@@ -24,16 +24,16 @@ package org.opendc.simulator.flow
 
 import io.mockk.*
 import org.junit.jupiter.api.*
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.internal.FlowConsumerContextImpl
 import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.kotlin.runSimulation
 
 /**
  * A test suite for the [FlowConsumerContextImpl] class.
  */
 class FlowConsumerContextTest {
     @Test
-    fun testFlushWithoutCommand() = runBlockingSimulation {
+    fun testFlushWithoutCommand() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val consumer = object : FlowSource {
             override fun onPull(conn: FlowConnection, now: Long): Long {
@@ -54,7 +54,7 @@ class FlowConsumerContextTest {
     }
 
     @Test
-    fun testDoubleStart() = runBlockingSimulation {
+    fun testDoubleStart() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val consumer = object : FlowSource {
             override fun onPull(conn: FlowConnection, now: Long): Long {
@@ -79,7 +79,7 @@ class FlowConsumerContextTest {
     }
 
     @Test
-    fun testIdempotentCapacityChange() = runBlockingSimulation {
+    fun testIdempotentCapacityChange() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val consumer = spyk(object : FlowSource {
             override fun onPull(conn: FlowConnection, now: Long): Long {
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
index 8b090593..2025dd52 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowForwarderTest.kt
@@ -28,16 +28,16 @@ import org.junit.jupiter.api.Assertions.*
 import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertThrows
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.internal.FlowEngineImpl
 import org.opendc.simulator.flow.source.FixedFlowSource
+import org.opendc.simulator.kotlin.runSimulation
 
 /**
  * A test suite for the [FlowForwarder] class.
  */
 internal class FlowForwarderTest {
     @Test
-    fun testCancelImmediately() = runBlockingSimulation {
+    fun testCancelImmediately() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 2000.0)
@@ -56,7 +56,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testCancel() = runBlockingSimulation {
+    fun testCancel() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 2000.0)
@@ -83,7 +83,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testState() = runBlockingSimulation {
+    fun testState() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val consumer = object : FlowSource {
@@ -108,7 +108,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testCancelPendingDelegate() = runBlockingSimulation {
+    fun testCancelPendingDelegate() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
 
@@ -126,7 +126,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testCancelStartedDelegate() = runBlockingSimulation {
+    fun testCancelStartedDelegate() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 2000.0)
@@ -144,7 +144,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testCancelPropagation() = runBlockingSimulation {
+    fun testCancelPropagation() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 2000.0)
@@ -162,7 +162,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testExitPropagation() = runBlockingSimulation {
+    fun testExitPropagation() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine, isCoupled = true)
         val source = FlowSink(engine, 2000.0)
@@ -183,7 +183,7 @@ internal class FlowForwarderTest {
 
     @Test
     @Disabled // Due to Kotlin bug: https://github.com/mockk/mockk/issues/368
-    fun testAdjustCapacity() = runBlockingSimulation {
+    fun testAdjustCapacity() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val sink = FlowSink(engine, 1.0)
@@ -202,7 +202,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testCounters() = runBlockingSimulation {
+    fun testCounters() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 1.0)
@@ -224,7 +224,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testCoupledExit() = runBlockingSimulation {
+    fun testCoupledExit() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine, isCoupled = true)
         val source = FlowSink(engine, 2000.0)
@@ -239,7 +239,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testPullFailureCoupled() = runBlockingSimulation {
+    fun testPullFailureCoupled() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine, isCoupled = true)
         val source = FlowSink(engine, 2000.0)
@@ -262,7 +262,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testStartFailure() = runBlockingSimulation {
+    fun testStartFailure() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 2000.0)
@@ -290,7 +290,7 @@ internal class FlowForwarderTest {
     }
 
     @Test
-    fun testConvergeFailure() = runBlockingSimulation {
+    fun testConvergeFailure() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val forwarder = FlowForwarder(engine)
         val source = FlowSink(engine, 2000.0)
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
index 726ddbf7..22a84edb 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/FlowSinkTest.kt
@@ -27,17 +27,17 @@ import io.mockk.verify
 import kotlinx.coroutines.*
 import org.junit.jupiter.api.*
 import org.junit.jupiter.api.Assertions.assertEquals
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.internal.FlowEngineImpl
 import org.opendc.simulator.flow.source.FixedFlowSource
 import org.opendc.simulator.flow.source.FlowSourceRateAdapter
+import org.opendc.simulator.kotlin.runSimulation
 
 /**
  * A test suite for the [FlowSink] class.
  */
 internal class FlowSinkTest {
     @Test
-    fun testSpeed() = runBlockingSimulation {
+    fun testSpeed() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
@@ -53,7 +53,7 @@ internal class FlowSinkTest {
     }
 
     @Test
-    fun testAdjustCapacity() = runBlockingSimulation {
+    fun testAdjustCapacity() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val provider = FlowSink(engine, 1.0)
 
@@ -69,7 +69,7 @@ internal class FlowSinkTest {
     }
 
     @Test
-    fun testSpeedLimit() = runBlockingSimulation {
+    fun testSpeedLimit() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
@@ -89,7 +89,7 @@ internal class FlowSinkTest {
      * [FlowSource.onPull].
      */
     @Test
-    fun testIntermediateInterrupt() = runBlockingSimulation {
+    fun testIntermediateInterrupt() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
@@ -109,7 +109,7 @@ internal class FlowSinkTest {
     }
 
     @Test
-    fun testInterrupt() = runBlockingSimulation {
+    fun testInterrupt() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
@@ -144,7 +144,7 @@ internal class FlowSinkTest {
     }
 
     @Test
-    fun testFailure() = runBlockingSimulation {
+    fun testFailure() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
@@ -165,7 +165,7 @@ internal class FlowSinkTest {
     }
 
     @Test
-    fun testExceptionPropagationOnNext() = runBlockingSimulation {
+    fun testExceptionPropagationOnNext() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
@@ -190,7 +190,7 @@ internal class FlowSinkTest {
     }
 
     @Test
-    fun testConcurrentConsumption() = runBlockingSimulation {
+    fun testConcurrentConsumption() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
@@ -206,7 +206,7 @@ internal class FlowSinkTest {
     }
 
     @Test
-    fun testCancelDuringConsumption() = runBlockingSimulation {
+    fun testCancelDuringConsumption() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
         val capacity = 4200.0
         val provider = FlowSink(engine, capacity)
@@ -225,7 +225,7 @@ internal class FlowSinkTest {
     @Test
     fun testInfiniteSleep() {
         assertThrows<IllegalStateException> {
-            runBlockingSimulation {
+            runSimulation {
                 val engine = FlowEngineImpl(coroutineContext, clock)
                 val capacity = 4200.0
                 val provider = FlowSink(engine, capacity)
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ForwardingFlowMultiplexerTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ForwardingFlowMultiplexerTest.kt
index ef15f711..cfd2bdf0 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ForwardingFlowMultiplexerTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/ForwardingFlowMultiplexerTest.kt
@@ -27,12 +27,12 @@ import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertAll
 import org.junit.jupiter.api.assertThrows
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.*
 import org.opendc.simulator.flow.internal.FlowEngineImpl
 import org.opendc.simulator.flow.source.FixedFlowSource
 import org.opendc.simulator.flow.source.FlowSourceRateAdapter
 import org.opendc.simulator.flow.source.TraceFlowSource
+import org.opendc.simulator.kotlin.runSimulation
 
 /**
  * Test suite for the [ForwardingFlowMultiplexer] class.
@@ -42,7 +42,7 @@ internal class ForwardingFlowMultiplexerTest {
      * Test a trace workload.
      */
     @Test
-    fun testTrace() = runBlockingSimulation {
+    fun testTrace() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
 
         val speed = mutableListOf<Double>()
@@ -79,7 +79,7 @@ internal class ForwardingFlowMultiplexerTest {
      * Test runtime workload on hypervisor.
      */
     @Test
-    fun testRuntimeWorkload() = runBlockingSimulation {
+    fun testRuntimeWorkload() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
 
         val duration = 5 * 60L * 1000
@@ -101,7 +101,7 @@ internal class ForwardingFlowMultiplexerTest {
      * Test two workloads running sequentially.
      */
     @Test
-    fun testTwoWorkloads() = runBlockingSimulation {
+    fun testTwoWorkloads() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
 
         val duration = 5 * 60L * 1000
@@ -140,7 +140,7 @@ internal class ForwardingFlowMultiplexerTest {
      * Test concurrent workloads on the machine.
      */
     @Test
-    fun testConcurrentWorkloadFails() = runBlockingSimulation {
+    fun testConcurrentWorkloadFails() = runSimulation {
         val engine = FlowEngineImpl(coroutineContext, clock)
 
         val switch = ForwardingFlowMultiplexer(engine)
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
index 6e2cdb98..4e242292 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/mux/MaxMinFlowMultiplexerTest.kt
@@ -27,19 +27,19 @@ import kotlinx.coroutines.launch
 import kotlinx.coroutines.yield
 import org.junit.jupiter.api.*
 import org.junit.jupiter.api.Assertions.assertEquals
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.FlowSink
 import org.opendc.simulator.flow.consume
 import org.opendc.simulator.flow.internal.FlowEngineImpl
 import org.opendc.simulator.flow.source.FixedFlowSource
 import org.opendc.simulator.flow.source.TraceFlowSource
+import org.opendc.simulator.kotlin.runSimulation
 
 /**
  * Test suite for the [FlowMultiplexer] implementations
  */
 internal class MaxMinFlowMultiplexerTest {
     @Test
-    fun testSmoke() = runBlockingSimulation {
+    fun testSmoke() = runSimulation {
         val scheduler = FlowEngineImpl(coroutineContext, clock)
         val switch = MaxMinFlowMultiplexer(scheduler)
 
@@ -61,7 +61,7 @@ internal class MaxMinFlowMultiplexerTest {
      * Test overcommitting of resources via the hypervisor with a single VM.
      */
     @Test
-    fun testOvercommittedSingle() = runBlockingSimulation {
+    fun testOvercommittedSingle() = runSimulation {
         val scheduler = FlowEngineImpl(coroutineContext, clock)
 
         val duration = 5 * 60L
@@ -99,7 +99,7 @@ internal class MaxMinFlowMultiplexerTest {
      * Test overcommitting of resources via the hypervisor with two VMs.
      */
     @Test
-    fun testOvercommittedDual() = runBlockingSimulation {
+    fun testOvercommittedDual() = runSimulation {
         val scheduler = FlowEngineImpl(coroutineContext, clock)
 
         val duration = 5 * 60L
diff --git a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/source/FixedFlowSourceTest.kt b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/source/FixedFlowSourceTest.kt
index 8396d346..552579ff 100644
--- a/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/source/FixedFlowSourceTest.kt
+++ b/opendc-simulator/opendc-simulator-flow/src/test/kotlin/org/opendc/simulator/flow/source/FixedFlowSourceTest.kt
@@ -24,17 +24,17 @@ package org.opendc.simulator.flow.source
 
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test
-import org.opendc.simulator.core.runBlockingSimulation
 import org.opendc.simulator.flow.FlowSink
 import org.opendc.simulator.flow.consume
 import org.opendc.simulator.flow.internal.FlowEngineImpl
+import org.opendc.simulator.kotlin.runSimulation
 
 /**
  * A test suite for the [FixedFlowSource] class.
  */
 internal class FixedFlowSourceTest {
     @Test
-    fun testSmoke() = runBlockingSimulation {
+    fun testSmoke() = runSimulation {
         val scheduler = FlowEngineImpl(coroutineContext, clock)
         val provider = FlowSink(scheduler, 1.0)
 
@@ -45,7 +45,7 @@ internal class FixedFlowSourceTest {
     }
 
     @Test
-    fun testUtilization() = runBlockingSimulation {
+    fun testUtilization() = runSimulation {
         val scheduler = FlowEngineImpl(coroutineContext, clock)
         val provider = FlowSink(scheduler, 1.0)