From: jkauttio <jkauttio@ac1ea38d-2e2b-0410-8846-a27921b304fc>
Date: Thu, 24 Oct 2013 12:30:56 +0000 (+0000)
Subject: Add a special "time" variable to the solver that always refers to the current simulat... 
X-Git-Tag: 1.8.1~224
X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=commitdiff_plain;h=5870c937177f4ee6b3ac0b5e4fb2789ee00f4a01;p=simantics%2Fsysdyn.git

Add a special "time" variable to the solver that always refers to the current simulation time.

refs #4488

git-svn-id: https://www.simantics.org/svn/simantics/sysdyn/trunk@28116 ac1ea38d-2e2b-0410-8846-a27921b304fc
---

diff --git a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Declaration.java b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Declaration.java
index 6dd7532a..cb04716a 100644
--- a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Declaration.java
+++ b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Declaration.java
@@ -1,14 +1,8 @@
 package fi.semantum.sysdyn.solver;
 
-import java.util.Arrays;
-
 public class Declaration implements IExpression {
 
 	public Variable variable;
-	
-//	public String name;
-//	public int[] subscripts;
-	
 	public Object modification;
 	
 	public Declaration(Variable variable, Object modification) {
diff --git a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Environment.java b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Environment.java
index f2ab66bc..d6beb34f 100644
--- a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Environment.java
+++ b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Environment.java
@@ -41,17 +41,17 @@ public class Environment implements IEnvironment, ISystem {
 	
 	public Model model;
 	public final double step;
-	public double time = 0;
+	public double time;
 	public boolean initial = true;
 	
 	public Object[] valueTable;
 
 	HashMap<String,TreeMap<Double,Double>> history = new HashMap<String,TreeMap<Double,Double>>();
 
-	public Environment(Model model, double step) {
-		
+	public Environment(Model model, double step, double start) {
 		this.model = model;
 		this.step = step;
+		this.time = start;
 		
 		model.functions.put("size", new Fn1() {
 
@@ -287,8 +287,9 @@ public class Environment implements IEnvironment, ISystem {
 			values.put(v.toString(), (Double)getValue(v.index(this)));
 		}
 		
-		// not completely sure if these should be included or what else should
-		// be included in the results
+		// NOTE: there is room for optimization as parameter values that do not
+		// change should only be obtained once (and parameter values that do
+		// change are (possibly) included in assignments or derivatives)
 		for (ParameterDeclaration p : model.parameters) {
 			Variable v = p.variable;
 			values.put(v.toString(), (Double)getValue(v.index(this)));
diff --git a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Parser.java b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Parser.java
index fbdc6cc6..55710051 100644
--- a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Parser.java
+++ b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Parser.java
@@ -269,6 +269,9 @@ public class Parser {
 			if(n.jjtGetNumChildren() == 1) {
 				return new Variable(currentFrame, n.op, (IExpression[])walk((SimpleNode)n.jjtGetChild(0), indent+2, model));
 			} else {
+				if ("time".equals(n.op)) {
+					return new TimeVariable();
+				}
 				return new Variable(currentFrame, n.op, null);
 			}
 		case relation:
diff --git a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Solver.java b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Solver.java
index dfcbcc89..b4e55d27 100644
--- a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Solver.java
+++ b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/Solver.java
@@ -14,11 +14,13 @@ public class Solver {
 	private Object[] newValues;
 	
 	private double step;
+	private double start;
 	private NodeCache cache;
 	private boolean ready;
 	
 	public Solver() {
 		step = 0.1;
+		start = 0;
 		// is it okay to store the cache with the solver instance?
 		cache = new NodeCache();
 		ready = false;
@@ -29,12 +31,17 @@ public class Solver {
 		ready = false;
 	}
 	
+	public void setStart(double start) {
+		this.start = start;
+		ready = false;
+	}
+	
 	public void prepare(String input) throws Exception {
 		LineReader reader = new LineReader(input, cache);
 		reader.parse();
 		
 		model = reader.model;
-		env = new Environment(model, step);
+		env = new Environment(model, step, start);
 		
 		int size = model.prepare();
 		
@@ -136,6 +143,9 @@ public class Solver {
 		Assignment[] assignments = model.assignmentArray;
 		Assignment[] derivatives = model.derivativeArray;
 		
+		// should probably be wrapped inside a method or something
+		env.time += env.step;
+		
 		// Solve algebraic equations
 		for(int i=0;i<assignments.length;i++) {
 			newValues[i] = assignments[i].expression.evaluate(env);
@@ -151,7 +161,6 @@ public class Solver {
 		for(int i=0;i<model.derivatives.size();i++) {
 			derivatives[i].target.assign(env, newValues[i]);
 		}
-		
 	}
 	
 	// TODO: implement some on the fly parameter change stuff for different experiment types
diff --git a/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/TimeVariable.java b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/TimeVariable.java
new file mode 100644
index 00000000..4049f7fa
--- /dev/null
+++ b/fi.semantum.sysdyn.solver/src/fi/semantum/sysdyn/solver/TimeVariable.java
@@ -0,0 +1,16 @@
+package fi.semantum.sysdyn.solver;
+
+public class TimeVariable implements IExpression {
+
+	@Override
+	public Object evaluate(IEnvironment environment) {
+		// possibly a bit ugly
+		return environment.getSystem().time();
+	}
+
+	@Override
+	public String toString() {
+		return "time";
+	}
+	
+}
diff --git a/org.simantics.sysdyn/src/org/simantics/sysdyn/solver/InternalSolver.java b/org.simantics.sysdyn/src/org/simantics/sysdyn/solver/InternalSolver.java
index 66e18ee6..db1f4eb9 100644
--- a/org.simantics.sysdyn/src/org/simantics/sysdyn/solver/InternalSolver.java
+++ b/org.simantics.sysdyn/src/org/simantics/sysdyn/solver/InternalSolver.java
@@ -85,6 +85,7 @@ public class InternalSolver implements ISolver {
 			interval = step;
 		
 		solver.setStep(step);
+		solver.setStart(start);
 	}
 
 	@Override