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 ("".equals(startTime.trim())){
  31                         startTime = "0";
  32                 }
  33                 if ("".equals(endTime.trim())){
  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          * Sets the actual expression string for this expression
  47          */
  48         private void setExpressions(String start, String end){
  49
  50                 startBuilder = new ExpressionBuilder(start);
  51                 endBuilder = new ExpressionBuilder(end);
  52                 for (String n : getAllSymbols()){
  53                         startBuilder.withVariable(new Variable(n));
  54                         endBuilder.withVariable(new Variable(n));
  55                 }
  56         }
  57
  58         @Override
  59         public Variable evaluate(SimulationStatus status){
  60
  61                 Calculable startCalc = buildExpression(startBuilder);
  62                 Calculable endCalc = buildExpression(endBuilder);
  63                 if (startCalc == null || endCalc == null){
  64                         return new Variable("Unknown");
  65                 }
  66
  67                 // Set the variables in the start and end calculators
  68                 for (FlightDataType type : status.getFlightData().getTypes()){
  69                         double value = status.getFlightData().getLast(type);
  70                         startCalc.setVariable( new Variable(type.getSymbol(), value ) );
  71                         endCalc.setVariable( new Variable(type.getSymbol(), value ) );
  72                 }
  73
  74                 // From the given datatype, get the time and function values and make an interpolator
  75
  76                 //Note: must get in a way that flight data system will figure out units. Otherwise there will be a type conflict when we get the new data.
  77                 FlightDataType type = FlightDataType.getType(null, getSymbol(), null);
  78
  79                 List<Double> data = status.getFlightData().get(type);
  80                 List<Double> time = status.getFlightData().get(FlightDataType.TYPE_TIME);
  81                 LinearInterpolator interp = new LinearInterpolator(time, data);
  82
  83                 // Evaluate the expression to get the start and end of the range
  84                 double startTime, endTime;
  85                 try{
  86                         startTime = startCalc.calculate().getDoubleValue();
  87                         startTime = MathUtil.clamp(startTime, 0, Double.MAX_VALUE);
  88
  89                         endTime = endCalc.calculate().getDoubleValue();
  90                         endTime = MathUtil.clamp(endTime, 0, time.get(time.size()-1));
  91                 }
  92                 catch (java.util.EmptyStackException e){
  93                         log.user("Unable to calculate time index for range expression "+getSymbol()+" due to empty stack exception");
  94                         return new Variable("Unknown");
  95                 }
  96
  97                 // generate an array representing the range
  98                 double step = status.getSimulationConditions().getSimulation().getOptions().getTimeStep();
  99                 double[] t = ArrayUtils.range(startTime, endTime,  step);
 100                 double[] y = new double[t.length];
 101                 int i = 0;
 102                 for (double tval : t){
 103                         y[i] = interp.getValue( tval );
 104                         i++;
 105                 }
 106
 107                 Variable result;
 108                 if (y.length == 0){
 109                         result = new Variable("Unknown");
 110                 }
 111                 else {
 112                         result = new Variable(hash(), y, startTime, step);
 113                 }
 114
 115                 return result;
 116         }
 117 }