git.gag.com Git - debian/openrocket/blob - core/src/net/sf/openrocket/simulation/customexpression/RangeExpression.java

   1 /*
   2  * A range expression contains two indexExpressions for the beginning and end time index of a range
   3  */
   4
   5 package net.sf.openrocket.simulation.customexpression;
   6
   7 import java.util.List;
   8
   9 import de.congrace.exp4j.Calculable;
  10 import de.congrace.exp4j.ExpressionBuilder;
  11 import de.congrace.exp4j.Variable;
  12 import net.sf.openrocket.document.OpenRocketDocument;
  13 import net.sf.openrocket.logging.LogHelper;
  14 import net.sf.openrocket.simulation.customexpression.CustomExpression;
  15 import net.sf.openrocket.simulation.FlightDataType;
  16 import net.sf.openrocket.simulation.SimulationStatus;
  17 import net.sf.openrocket.startup.Application;
  18 import net.sf.openrocket.util.ArrayUtils;
  19 import net.sf.openrocket.util.LinearInterpolator;
  20 import net.sf.openrocket.util.MathUtil;
  21
  22 public class RangeExpression extends CustomExpression {
  23         private static final LogHelper log = Application.getLogger();
  24
  25         private ExpressionBuilder startBuilder, endBuilder;
  26
  27         public RangeExpression(OpenRocketDocument doc, String startTime, String endTime, String variableType) {
  28                 super(doc);
  29
  30                 if (startTime.isEmpty()){
  31                         startTime = "0";
  32                 }
  33                 if (endTime.isEmpty()){
  34                         endTime = "t";
  35                 }
  36
  37                 this.setName("");
  38                 this.setSymbol(variableType);
  39                 this.setExpressions(startTime, endTime);
  40                 this.expression = variableType+startTime+endTime; // this is used just for generating the hash
  41
  42                 log.info("New range expression, "+startTime + " to "+endTime);
  43
  44         }
  45
  46         /*
  47          * Sets the actual expression string for this expression
  48          */
  49         private void setExpressions(String start, String end){
  50
  51                 startBuilder = new ExpressionBuilder(start);
  52                 endBuilder = new ExpressionBuilder(end);
  53                 for (String n : getAllSymbols()){
  54                         startBuilder.withVariable(new Variable(n));
  55                         endBuilder.withVariable(new Variable(n));
  56                 }
  57         }
  58
  59         @Override
  60         public Variable evaluate(SimulationStatus status){
  61
  62                 Calculable startCalc = buildExpression(startBuilder);
  63                 Calculable endCalc = buildExpression(endBuilder);
  64                 if (startCalc == null || endCalc == null){
  65                         return new Variable("Unknown");
  66                 }
  67
  68                 // Set the variables in the start and end calculators
  69                 for (FlightDataType type : status.getFlightData().getTypes()){
  70                         double value = status.getFlightData().getLast(type);
  71                         startCalc.setVariable( new Variable(type.getSymbol(), value ) );
  72                         endCalc.setVariable( new Variable(type.getSymbol(), value ) );
  73                 }
  74
  75                 // From the given datatype, get the time and function values and make an interpolator
  76                 FlightDataType type = getType();
  77
  78                 List<Double> data = status.getFlightData().get(type);
  79                 List<Double> time = status.getFlightData().get(FlightDataType.TYPE_TIME);
  80                 LinearInterpolator interp = new LinearInterpolator(time, data);
  81
  82                 // Evaluate the expression to get the start and end of the range
  83                 double startTime, endTime;
  84                 try{
  85                         startTime = startCalc.calculate().getDoubleValue();
  86                         startTime = MathUtil.clamp(startTime, 0, Double.MAX_VALUE);
  87
  88                         endTime = endCalc.calculate().getDoubleValue();
  89                         endTime = MathUtil.clamp(endTime, 0, time.get(time.size()-1));
  90                 }
  91                 catch (java.util.EmptyStackException e){
  92                         log.user("Unable to calculate time index for range expression "+getSymbol()+" due to empty stack exception");
  93                         return new Variable("Unknown");
  94                 }
  95
  96                 // generate an array representing the range
  97                 double step = status.getSimulationConditions().getSimulation().getOptions().getTimeStep();
  98                 double[] t = ArrayUtils.range(startTime, endTime,  step);
  99                 double[] y = new double[t.length];
 100                 int i = 0;
 101                 for (double tval : t){
 102                         y[i] = interp.getValue( tval );
 103                         i++;
 104                 }
 105
 106                 Variable result;
 107                 if (y.length == 0){
 108                         result = new Variable("Unknown");
 109                 }
 110                 else {
 111                         result = new Variable(hash(), y, startTime, step);
 112                 }
 113
 114                 return result;
 115         }
 116 }