public CoolerCollection(string dataFile, string schemaFile)
{
XPathNavigator navigator = openDocumentForReading(dataFile, schemaFile);
if (!navigator.MoveToChild("coolers", ""))
{
throw new Exception("XML Parsing error");
}
if (!navigator.MoveToChild("cooler", ""))
{
throw new Exception("XML Parsing error");
}
do
{
Cooler cooler = new Cooler(navigator.Clone());
objectList.Add(cooler);
} while (navigator.MoveToNext());
}
public CandidateSolution(Material m, Cooler c, double targetTemp, double strengthRequirement, Problem problem)
{
material = m;
cooler = c;
// If yieldStrength < 0, that means the value is unknown. We cannot use materials without knowing
// their yieldStrength, so solutions with this material are not feasible.
if (m.yieldStrength < 0.0)
{
feasible = false;
return;
}
// The lowest temp for which we have thermal conductivity data for a particular material sets an effective
// lower bound on target temp. We cannot use materials in a situation where they will be outside the
// temperature range where we know this property.
double minThermalData = m.MP[0].temp;
if (targetTemp <= minThermalData)
{
feasible = false;
return;
}
// The strut(s) must be strong enough to support the load. Figure out what the minimum cross section
// is. This is the cross section for each strut.
strutCrossSection = strengthRequirement / m.yieldStrength / problem.SupportNumber;
strutCrossSection *= 1.00001; // add tiny bit to avoid precision problems when comparing later
double calcStrength = m.yieldStrength * strutCrossSection * problem.SupportNumber;
if (calcStrength < strengthRequirement)
{
throw new Exception("We have a math precision problem here");
}
// If the material is not strong enough to support the load given the maximum cross section
// specified in the problem, it's not feasible
if (strutCrossSection > problem.MaxStrutCrossSection)
{
feasible = false;
return;
}
// If the material is so strong that a cross section less than the minimum specified can support the
// load, we have to adjust the cross section to the minimum specified.
if (strutCrossSection < problem.MinStrutCrossSection)
{
strutCrossSection = problem.MinStrutCrossSection;
}
// Need to determine the maximum power factor which will result in an input power that meets
// the problem constraints. We will always use the maximum power factor which does not violate
// our input power constraint as we are only optimizing our cost to build (not operating costs).
coolerPowerFactor = c.maxPowerFactor(problem.InputPowerLimit, targetTemp);
double actualInputPower = c.InputPower(targetTemp, coolerPowerFactor);
if (actualInputPower > problem.InputPowerLimit)
{
throw new Exception("Error in maxPowerFactor calculation");
}
// Given the cooler, material, cross section, target temperature, and power factor, we can calculate the
// minimum strut length which will allow us to reach that temperature.
strutLength = Optimizer.steadyStateSim.strutLength(targetTemp, strutCrossSection * problem.SupportNumber, m, c, coolerPowerFactor);
// If the Matlab code cannot come up with a minimum strut length, the mateial is not feasible
// given the other parameters.
if (double.IsNaN(strutLength))
{
feasible = false;
return;
}
// If reaching the target temperature requires a longer strut than the maximum length specified,
// the material is not feasible.
if (strutLength > problem.MaxStrutLength)
{
feasible = false;
return;
}
// If we can reach the target temperature with a strut shorter than the minimum, we still have to
// use a strut that meets the minimum length requirement.
if (strutLength < problem.MinStrutLength)
{
strutLength = problem.MinStrutLength;
// Now that we have adjusted the strutLength to be longer, we'll reach a colder temperature.
// It could be that we are now below the min temp for which we have data on our strut material.
double steadyStateTemp;
try {
steadyStateTemp = Optimizer.steadyStateSim.simulate(strutLength, strutCrossSection * problem.SupportNumber, material, cooler, coolerPowerFactor);
} catch (ArgumentException) {
steadyStateTemp = -1;
}
if (steadyStateTemp < minThermalData)
{
// Here we reduce the power factor enough to get the temperature back in range.
coolerPowerFactor = MaxPowerFactor(0.0, coolerPowerFactor, minThermalData, problem);
}
}
// OK, we have a feasible solution - figure out what it's going to cost.
feasible = true;
double strutVolume = strutCrossSection * strutLength * problem.SupportNumber;
double strutCost = m.price * strutVolume;
solutionCost = c.price + strutCost;
}
public double simulate(double length, double crossSection, Material material, Cooler cooler, double powerFactor)
{
double[,] data = cooler.getDataNative("CPM");
for (int i = 0; i < data.GetLength(0); i++)
{
data[i, 0] = 300.0 - (300.0 - data[i, 0]) * powerFactor;
data[i, 1] *= powerFactor;
}
MWNumericArray coolerData = (MWNumericArray)data;
MWNumericArray materialData = material.getData("PM");
// We assume that if the MATLAB code generates an exception or returns NaN, it's becuase the parameters
// imply a system which is infeasible. That might mean that the steady state temperature would be below
// the lowest conductivity data point for the material.
try {
MWNumericArray ssTemp = (MWNumericArray)matlabSim.steadystatetemperature(length, crossSection, materialData, coolerData);
double answer = ssTemp.ToScalarDouble();
if (Double.IsNaN(answer))
{
throw new ArgumentException("Bad arguments to simulate method");
}
else
{
return(answer);
}
} catch (Exception ex) {
throw new ArgumentException("Bad arguments to simulate method", ex);
}
}
public double simulate(double length, double crossSection, Material material, Cooler cooler)
{
try {
MWNumericArray lengthData = new MWNumericArray(length);
MWNumericArray crossSectionData = new MWNumericArray(crossSection);
MWNumericArray materialData = material.getData("PM");
MWNumericArray coolerData = cooler.getData("CPM");
MWNumericArray ssTemp = (MWNumericArray)matlabSim.steadystatetemperature(
lengthData, crossSectionData, materialData, coolerData);
return(ssTemp.ToScalarDouble());
} catch (Exception ex) {
throw new ArgumentException("Bad arguments to simulate method", ex);
}
}
public double strutLength(double targetTemp, double crossSection, Material material, Cooler cooler, double powerFactor)
{
double[,] data = cooler.getDataNative("CPM");
for (int i = 0; i < data.GetLength(0); i++)
{
data[i, 0] = 300.0 - (300.0 - data[i, 0]) * powerFactor;
data[i, 1] *= powerFactor;
}
MWNumericArray targetTempData = new MWNumericArray(targetTemp);
MWNumericArray crossSectionData = new MWNumericArray(crossSection);
MWNumericArray materialData = material.getData("PM");
MWNumericArray coolerData = (MWNumericArray)data;
MWNumericArray strutLength = (MWNumericArray)matlabSim.strutlength(
targetTempData, crossSectionData, materialData, coolerData);
double answer = strutLength.ToScalarDouble();
return(answer);
}
public double strutLength(double targetTemp, double crossSection, Material material, Cooler cooler)
{
MWNumericArray targetTempData = new MWNumericArray(targetTemp);
MWNumericArray crossSectionData = new MWNumericArray(crossSection);
MWNumericArray materialData = material.getData("PM");
MWNumericArray coolerData = cooler.getData("CPM");
MWNumericArray strutLength = (MWNumericArray)matlabSim.strutlength(
targetTempData, crossSectionData, materialData, coolerData);
return(strutLength.ToScalarDouble());
}