git.gag.com Git - debian/openrocket/blob - core/src/de/congrace/exp4j/Example.java

   1 package de.congrace.exp4j;
   2
   3 import java.util.List;
   4
   5 public class Example {
   6
   7         public static void main(String[] args) throws UnknownFunctionException, UnparsableExpressionException, InvalidCustomFunctionException {
   8
   9                 // Test 1
  10                 // ======
  11
  12                 Calculable calc1 = new ExpressionBuilder("x * y - 2").withVariableNames("x", "y").build();
  13                 calc1.setVariable(new Variable("x", 1.2));
  14                 calc1.setVariable(new Variable("y", 2.2));
  15
  16                 System.out.println(calc1.calculate().toString());
  17                 //double result = calc1.calculate().getDoubleValue();
  18                 //System.out.println(result);
  19
  20                 // Test 2
  21                 // ======
  22
  23                 // A function which calculates the mean of an array and scales it
  24                 CustomFunction meanFn = new CustomFunction("mean",2) {
  25                     public Variable applyFunction(List<Variable> vars) {
  26
  27                         double[] vals;
  28                         double scale;
  29
  30                         try{
  31                                 vals = vars.get(0).getArrayValue();
  32                                 scale = vars.get(1).getDoubleValue();
  33                         } catch (Exception e) {
  34                                 return new Variable("Invalid");
  35                         }
  36
  37                         double subtotal = 0;
  38                         for (int i = 0; i < vals.length; i++ ){
  39                                 subtotal += vals[i];
  40                         }
  41
  42                         subtotal = scale * subtotal / vals.length;
  43                         return new Variable("double MEAN result, ", subtotal);
  44
  45                     }
  46                 };
  47
  48                 ExpressionBuilder b = new ExpressionBuilder("mean(x,y)");
  49                 b.withCustomFunction(meanFn);
  50                 b.withVariable(new Variable("x", new double[] {1.1,2,10,3,2.4,10.2}));
  51                 b.withVariable(new Variable("y", 2));
  52                 Calculable calc2 = b.build();
  53
  54                 System.out.println( calc2.calculate().toString() );
  55
  56                 // Test 3
  57                 // ======
  58
  59                 Calculable calc3 = new ExpressionBuilder("x * y - 2").withVariableNames("x", "y").build();
  60                 calc3.setVariable(new Variable("x", new double[]{1.2, 10, 20, 15}));
  61                 calc3.setVariable(new Variable("y", new double[]{2.2, 5.2, 12, 9 }));
  62
  63                 //double result3 = calc3.calculate().getDoubleValue();
  64                 System.out.println(calc3.calculate().toString());
  65
  66
  67                 // Test 4
  68                 // ======
  69
  70                 Calculable calc4 = new ExpressionBuilder("log10(sqrt(x) * abs(y))").withVariableNames("x", "y").build();
  71                 calc4.setVariable(new Variable("x", new double[]{1.2, 10, 10, 15}));
  72                 calc4.setVariable(new Variable("y", new double[]{2.2, -5.2, 5.2, 9 }));
  73
  74                 //double result3 = calc3.calculate().getDoubleValue();
  75                 System.out.println(calc4.calculate().toString());
  76         }
  77 }