allows recovering from oscillations

distribution/ReleaseNotes.txt

@@ -6,6 +6,7 @@ HEAD, planned as v0.31
 - FSM editor highlights the current transition
 - Adds drivers with inverted output
 - Adds a minified circuit as a new shape for embedded circuits
+- Allows recovering from oscillations.
 
 v0.30, released on 3. February 2023
 - Added a search function

src/main/java/de/neemann/digital/core/Model.java

@@ -80,6 +80,7 @@ public class Model implements Iterable<Node>, SyncAccess {
     private AsyncSeq asyncInfos;
     private boolean asyncMode = false;
     private boolean allowGlobalValues = false;
+    private boolean recoverFromOscillation = false;
     private File rootPath;
 
     private final ArrayList<ModelStateObserver> observers;
@@ -293,20 +294,21 @@ public class Model implements Iterable<Node>, SyncAccess {
         try {
             if (cond.doNextMicroStep()) {
                 int counter = 0;
+                oscillatingNodes = null;
                 while (cond.doNextMicroStep() && state != State.CLOSED) {
                     if (counter++ > oscillationDetectionCounter) {
                         if (oscillatingNodes == null)
                             oscillatingNodes = new HashSet<>();
                         if (counter > oscillationDetectionCounter + COLLECTING_LOOP_COUNTER_OFFS) {
-                            NodeException seemsToOscillate = new NodeException(Lang.get("err_seemsToOscillate")).addNodes(oscillatingNodes);
+                            throw new NodeException(Lang.get("err_seemsToOscillate")).addNodes(oscillatingNodes);
-                            oscillatingNodes = null;
-                            throw seemsToOscillate;
                         } else {
                             oscillatingNodes.addAll(nodesToUpdateNext);
                         }
-                    }
+                        doMicroStep(noise || recoverFromOscillation);
+                    } else {
                         doMicroStep(noise);
                     }
+                }
             } else {
                 // if a calculation is initiated but there is nothing to do because there was
                 // no gate input change, perform a burn check to detect short circuits caused by
@@ -947,6 +949,20 @@ public class Model implements Iterable<Node>, SyncAccess {
         return this;
     }
 
+    /**
+     * I set, the model tries to recover from oszillation by introducing noise
+     * to the model execution.
+     * Use with extreme care because is covers bugs in the simulation that lead
+     * to an unpredictable behaviour and makes the simulation very slow!
+     *
+     * @param recoverFromOscillation if true, the model tries to recover from an oszillation
+     * @return this for chained calls
+     */
+    public Model setRecoverFromOscillation(boolean recoverFromOscillation) {
+        this.recoverFromOscillation = recoverFromOscillation;
+        return this;
+    }
+
     /**
      * Sets async execution infos
      *

src/main/java/de/neemann/digital/core/element/Keys.java

@@ -566,7 +566,13 @@ public final class Keys {
             new Key.KeyInteger("oscillationDetectionCounter", 1000)
                     .setComboBoxValues(1000, 5000, 10000)
                     .setMin(1000)
-                    .setMax(100000);
+                    .setMax(100000).setSecondary();
+
+    /**
+     * Counter used to detect oscillations
+     */
+    public static final Key<Boolean> RECOVER_FROM_OSCILLATION =
+            new Key<>("recoverFromOscillation", false).setSecondary();
 
     /**
      * output format for numbers

src/main/java/de/neemann/digital/gui/Main.java

@@ -1475,6 +1475,8 @@ public final class Main extends JFrame implements ClosingWindowListener.ConfirmS
             modelCreator = new ModelCreator(circuitComponent.getCircuit(), library);
             model = modelCreator.createModel(true);
 
+            model.setRecoverFromOscillation(circuitComponent.getCircuit().getAttributes().get(Keys.RECOVER_FROM_OSCILLATION));
+
             time = System.currentTimeMillis() - time;
             LOGGER.debug("model creation: " + time + " ms, " + model.getNodes().size() + " nodes");
 

src/main/java/de/neemann/digital/gui/components/CircuitComponent.java

@@ -82,7 +82,6 @@ public class CircuitComponent extends JComponent implements ChangedListener, Lib
         ATTR_LIST.add(Keys.PINCOUNT);
         ATTR_LIST.add(Keys.BACKGROUND_COLOR);
         ATTR_LIST.add(Keys.DESCRIPTION);
-        ATTR_LIST.add(Keys.OSCILLATION_DETECTION_COUNTER);
         ATTR_LIST.add(Keys.LOCKED_MODE);
         ATTR_LIST.add(Keys.ROMMANAGER);
         ATTR_LIST.add(Keys.SHOW_DATA_TABLE);
@@ -94,6 +93,8 @@ public class CircuitComponent extends JComponent implements ChangedListener, Lib
         ATTR_LIST.add(Keys.BIG_ENDIAN_SETTING);
         ATTR_LIST.add(Keys.SKIP_HDL);
         ATTR_LIST.add(Keys.IS_GENERIC);
+        ATTR_LIST.add(Keys.OSCILLATION_DETECTION_COUNTER);
+        ATTR_LIST.add(Keys.RECOVER_FROM_OSCILLATION);
     }
 
 

src/main/resources/lang/lang_de.xml

@@ -1684,6 +1684,8 @@ Sind evtl. die Namen der Variablen nicht eindeutig?</string>
     <string name="key_oscillationDetectionCounter">Oszillationserkennung</string>
     <string name="key_oscillationDetectionCounter_tt">Anzahl der Gatterlaufzeiten, bei der eine Oszillation erkannt
         wird, wenn sich die Schaltung bis dahin noch nicht stabilisiert hat.</string>
+    <string name="key_recoverFromOscillation">Bei Oszillationen mit Zufallswerten weitermachen.</string>
+    <string name="key_recoverFromOscillation_tt">Wird diese Option gesetzt, wird das Verhalten der Simulation im Falle einer Oszillation unvorhersehbar und zudem extrem langsam!</string>
 
     <string name="key_telnetEscape">Telnet-Modus</string>
     <string name="key_telnetEscape_tt">Wenn gesetzt, werden die Telnet Steuerkommandos ausgewertet.

src/main/resources/lang/lang_en.xml

@@ -1667,6 +1667,8 @@
     <string name="key_oscillationDetectionCounter">Oscillation detection</string>
     <string name="key_oscillationDetectionCounter_tt">Number of gate propagation times at which a oscillation is
         detected if the circuit has not stabilized by then.</string>
+    <string name="key_recoverFromOscillation">In case of oscillations, continue with random values.</string>
+    <string name="key_recoverFromOscillation_tt">If this option is set, the behavior of the simulation becomes unpredictable and extremely slow if there is an oscillation!</string>
 
     <string name="key_telnetEscape">Telnet mode</string>
     <string name="key_telnetEscape_tt">If set, the Telnet control commands are evaluated.