public LGPInstruction Clone()
{
LGPInstruction clone = new LGPInstruction(mProgram);
clone.mProgram = mProgram;
clone.mIsStructuralIntron = mIsStructuralIntron;
clone.mOperator = mOperator;
clone.mOperand1 = mOperand1;
clone.mOperand2 = mOperand2;
clone.mDestinationRegister = mDestinationRegister;
return(clone);
}
public virtual double[] Execute(double [] register_values)
{
for (int i = 0; i < mRegisterSet.RegisterCount; ++i)
{
mRegisterSet.FindRegisterByIndex(i).Value = register_values[i % register_values.Length];
}
LGPOperator.OperatorExecutionStatus command = LGPOperator.OperatorExecutionStatus.LGP_EXECUTE_NEXT_INSTRUCTION;
LGPInstruction current_effective_instruction = null;
LGPInstruction prev_effective_instruction = null;
foreach (LGPInstruction instruction in mInstructions)
{
if (instruction.IsStructuralIntron)
{
continue;
}
prev_effective_instruction = current_effective_instruction;
current_effective_instruction = instruction;
if (command == LGPOperator.OperatorExecutionStatus.LGP_EXECUTE_NEXT_INSTRUCTION)
{
command = current_effective_instruction.Execute();
}
else
{
// Xianshun says:
// as suggested in Linear Genetic Programming
// the condictional construct is restricted to single condictional construct
// an example of single conditional construct would be
// line 1: if(register[a])
// line 2: <action1>
// line 3: <action2>
// if register[a]==true, then <action1> and <action2> are executed
// if register[a]==false, then <action1> is skipped and <action2> is executed
// <action1> and <action2> are restricted to effective instruction
if (prev_effective_instruction.IsConditionalConstruct)
{
command = LGPOperator.OperatorExecutionStatus.LGP_EXECUTE_NEXT_INSTRUCTION;
}
}
}
double[] outputs = new double[mRegisterSet.RegisterCount];
for (int i = 0; i < outputs.Length; ++i)
{
outputs[i] = mRegisterSet.FindRegisterByIndex(i).Value;
}
return(outputs);
}
public void MutateInstructionRegister()
{
LGPInstruction selected_instruction = mInstructions[Statistics.DistributionModel.NextInt(InstructionCount)];
double p_const = 0;
foreach (LGPInstruction instruction in mInstructions)
{
if (instruction.IsOperand1ConstantRegister || instruction.IsOperand2ConstantRegister)
{
p_const += 1.0;
}
}
p_const /= InstructionCount;
selected_instruction.MutateRegister(p_const);
}
public virtual void Create(int size)
{
if (!mSetup)
{
Setup();
}
// Xianshun says:
// In this method, the instruction created is not garanteed to be structurally effective
for (int i = 0; i < size; ++i)
{
LGPInstruction instruction = new LGPInstruction(this);
instruction.Create();
mInstructions.Add(instruction);
}
}
protected void ExecuteOnFitnessCase(LGPFitnessCase fitness_case)
{
mPop.InitializeProgramRegisters(this, fitness_case);
LGPOperator.OperatorExecutionStatus command = LGPOperator.OperatorExecutionStatus.LGP_EXECUTE_NEXT_INSTRUCTION;
LGPInstruction current_effective_instruction = null;
LGPInstruction prev_effective_instruction = null;
foreach (LGPInstruction instruction in mInstructions)
{
if (instruction.IsStructuralIntron)
{
continue;
}
prev_effective_instruction = current_effective_instruction;
current_effective_instruction = instruction;
if (command == LGPOperator.OperatorExecutionStatus.LGP_EXECUTE_NEXT_INSTRUCTION)
{
command = current_effective_instruction.Execute();
fitness_case.ReportProgress(instruction.Operator, instruction.Operand1, instruction.Operand2, instruction.DestinationRegister, RegisterSet);
}
else
{
// Xianshun says:
// as suggested in Linear Genetic Programming
// the condictional construct is restricted to single condictional construct
// an example of single conditional construct would be
// line 1: if(register[a])
// line 2: <action1>
// line 3: <action2>
// if register[a]==true, then <action1> and <action2> are executed
// if register[a]==false, then <action1> is skipped and <action2> is executed
// <action1> and <action2> are restricted to effective instruction
if (prev_effective_instruction.IsConditionalConstruct)
{
command = LGPOperator.OperatorExecutionStatus.LGP_EXECUTE_NEXT_INSTRUCTION;
}
}
}
double[] outputs = new double[mRegisterSet.RegisterCount];
for (int i = 0; i < outputs.Length; ++i)
{
outputs[i] = mRegisterSet.FindRegisterByIndex(i).Value;
}
fitness_case.RunLGPProgramCompleted(outputs);
}
/// <summary>
/// this is derived from the micro mutation implementation in section
/// 6.2.2 of Linear Genetic Programming
/// 1. randomly select an (effective) instruction with a constant c
/// 2. change constant c through a standard deviation from the current value
/// c:=c + normal(mean:=0, standard_deviation)
/// </summary>
public void MutateInstructionConstant(Statistics.Gaussian guass)
{
LGPInstruction selected_instruction = null;
foreach (LGPInstruction instruction in mInstructions)
{
if (!instruction.IsStructuralIntron && (instruction.IsOperand1ConstantRegister || instruction.IsOperand2ConstantRegister))
{
if (selected_instruction == null)
{
selected_instruction = instruction;
}
else if (Statistics.DistributionModel.GetUniform() < 0.5)
{
selected_instruction = instruction;
}
}
}
if (selected_instruction != null)
{
selected_instruction.MutateConstant(guass, MicroMutateConstantStandardDeviation);
}
}
public void MutateInstructionOperator()
{
LGPInstruction instruction = mInstructions[Statistics.DistributionModel.NextInt(InstructionCount)];
instruction.MutateOperator();
}
public void MarkStructuralIntrons(int stop_point, HashSet <int> Reff)
{
/*
* Source: Brameier, M 2004 On Linear Genetic Programming (thesis)
*
* Algorithm 3.1 (detection of structural introns)
* 1. Let set R_eff always contain all registers that are effective at the current program
* position. R_eff := { r | r is output register }.
* Start at the last program instruction and move backwards.
* 2. Mark the next preceding operation in program with:
* destination register r_dest element-of R_eff.
* If such an instruction is not found then go to 5.
* 3. If the operation directly follows a branch or a sequence of branches then mark these
* instructions too. Otherwise remove r_dest from R_eff .
* 4. Insert each source (operand) register r_op of newly marked instructions in R_eff
* if not already contained. Go to 2.
* 5. Stop. All unmarked instructions are introns.
*/
// Xianshun says:
// this is a variant of Algorithm 3.1 that run Algorithm 3.1 until stop_point and return the Reff at that stage
int instruction_count = mInstructions.Count;
for (int i = instruction_count - 1; i > stop_point; i--)
{
mInstructions[i].IsStructuralIntron = true;
}
Reff.Clear();
int register_count = mPop.RegisterCount;
for (int i = 0; i < register_count; ++i)
{
Reff.Add(i);
}
LGPInstruction current_instruction = null;
LGPInstruction prev_instruction = null;
for (int i = instruction_count - 1; i > stop_point; i--)
{
prev_instruction = current_instruction;
current_instruction = mInstructions[i];
// prev_instruction is not an structural intron and the current_instruction
// is a condictional construct then, the current_instruction is not structural intron either
// this directly follows from Step 3 of Algorithm 3.1
if (current_instruction.IsConditionalConstruct && prev_instruction != null)
{
if (!prev_instruction.IsStructuralIntron)
{
current_instruction.IsStructuralIntron = false;
}
}
else
{
if (Reff.Contains(current_instruction.DestinationRegisterIndex))
{
current_instruction.IsStructuralIntron = false;
Reff.Remove(current_instruction.DestinationRegisterIndex);
if (!current_instruction.IsOperand1ConstantRegister)
{
Reff.Add(current_instruction.Operand1RegisterIndex);
}
if (!current_instruction.IsOperand2ConstantRegister)
{
Reff.Add(current_instruction.Operand2RegisterIndex);
}
}
}
}
}
