Need Advice on working with Arrays

• Tuesday, January 17, 2012 11:20 PM

   

   
  

  0

  I'm puzzled about how to remove the explicit C++ loops from the portion of the example model shown below starting from the line

  	for (int i = 0; i < numberOfBalanceSections; i++)
  

  I look forward to any suggestions...

       void example1Model()
        {
           int numberOfMeters = 6;
           int numberOfBalanceSections = numberOfMeters - 1;
           int numberOfObservations = 25;
  
           var NumberOfMeters = Variable.New<int>().Named("M");
           var NumberOfObservations = Variable.New<int>().Named("N");
           var NumberOfBalanceSections = Variable.New<int>().Named("S");
  
           NumberOfMeters.ObservedValue = numberOfMeters;
           NumberOfBalanceSections.ObservedValue = numberOfBalanceSections;
           NumberOfObservations.ObservedValue = numberOfObservations;
  
           Range m = new Range(NumberOfMeters).Named("m");
           Range n = new Range(NumberOfObservations).Named("n");
           Range s = new Range(NumberOfBalanceSections).Named("s");
  
           var TrueFlow = Variable.Array(Variable.Array<double>(n), m).Named("TrueFlow");
           var TruePackingRate = Variable.Array(Variable.Array<double>(n), s).Named("TruePackingRate");
  
           // TrueFlow & TruePackingRate are hooked up to a number of other
           // random variables (not shown)
           // ...
  
           // Each balance section has a set of flows in and a set of flows out
           int[][] flowsOut = new int[numberOfBalanceSections][];
           int[][] flowsIn = new int[numberOfBalanceSections][];
           // Set up flowsOut and flowsIn ...
  
           Variable<double> AlmostZero = 
              Variable.GaussianFromMeanAndVariance(0, 0.01).Named("AlmostZero");
  
           // How is the following set up neatly in infer.Net
           for (int i = 0; i < numberOfBalanceSections; i++)
           {
              Range c = new Range(1 + flowsIn[i].Length + flowsOut[i].Length);
              using (Variable.ForEach(n))
              {
                 var flows = Variable.Array<double>(c).Named("flows" + i);
                 for (int j = 0; j < flowsIn[i].Length; j++)
                 {
                    flows[j] = TrueFlow[flowsIn[i][j]][n];
                 }
                 for (int j = 0; j < flowsOut[i].Length; j++)
                 {
                    flows[j + flowsIn[i].Length] = -TrueFlow[flowsOut[i][j]][n];
                 }
                 flows[flowsIn[i].Length + flowsOut[i].Length] = -TruePackingRate[i][n];
                 var vb = Variable.Sum(flows).Named("VolumeBalance" + i);
                 Variable.ConstrainEqual(vb, AlmostZero);
              }
           }  
        }

  
  

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  Oopsnut
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