public static IiList Ii_Calc(double th, CATItems it, string model, double D)
{
IiList objIi = null;
double[] Ii = null; double[] dIi = null; double[] d2Ii = null;
try
{
if (String.IsNullOrEmpty(model))
{
#region "Calculation for Dichotmous Items"
double[] P = null; double[] dP = null; double[] d2P = null; double[] d3P = null;
PiList pr = Pi.Pi_Calc(th, it, model, D); // Check return value of Pi
if (pr == null)
{
objIi = new IiList();
objIi.Exception = "No Pi values found!";
return(objIi);
}
P = pr.Pi;
dP = pr.dPi;
d2P = pr.d2Pi;
d3P = pr.d3Pi;
Ii = new double[dP.Length];
dIi = new double[d2P.Length];
d2Ii = new double[d3P.Length];
objIi = new IiList(P.Length);
double[] Q = new double[P.Length];
for (int i = 0; i < P.Length; i++)
{
Q[i] = 1 - P[i];
}
for (int j = 0; j < Ii.Length; j++)
{
Ii[j] = Math.Pow(dP[j], 2) / (P[j] * Q[j]);
}
for (int k = 0; k < dIi.Length; k++)
{
dIi[k] = dP[k] * (2 * P[k] * Q[k] * d2P[k] - Math.Pow(dP[k], 2) * (Q[k] - P[k])) / (Math.Pow(P[k], 2) * Math.Pow(Q[k], 2));
}
for (int l = 0; l < d2Ii.Length; l++)
{
d2Ii[l] = (2 * P[l] * Q[l] * (Math.Pow(d2P[l], 2) + dP[l] * d3P[l]) - 2 * Math.Pow(dP[l], 2) * d2P[l] * (Q[l] - P[l])) / (Math.Pow(P[l], 2) * Math.Pow(Q[l], 2)) -
(3 * Math.Pow(P[l], 2) * Q[l] * Math.Pow(dP[l], 2) * d2P[l] - P[l] * Math.Pow(dP[l], 4) * (2 * Q[l] - P[l])) / (Math.Pow(P[l], 4) * Math.Pow(Q[l], 2)) +
(3 * P[l] * Math.Pow(Q[l], 2) * Math.Pow(dP[l], 2) * d2P[l] - Q[l] * Math.Pow(dP[l], 4) * (Q[l] - 2 * P[l])) / (Math.Pow(P[l], 2) * Math.Pow(Q[l], 4));
}
#endregion
}
else
{
#region "Calculation for Polytomous Items"
double[,] P = null; double[,] dP = null; double[,] d2P = null; double[,] d3P = null;
PiListPoly pr = Pi.Pi_Poly_Calc(th, it, model, D);
if (pr == null)
{
objIi = new IiList();
objIi.Exception = "No Pi values found!";
return(objIi);
}
P = pr.Pi;
dP = pr.dPi;
d2P = pr.d2Pi;
d3P = pr.d3Pi;
int rowLength = pr.Pi.GetLength(0);
int columnLength = pr.Pi.GetLength(1);
objIi = new IiList(rowLength);
double[,] pr0 = new double[rowLength, columnLength];
double[,] pr1 = new double[rowLength, columnLength];
double[,] pr2 = new double[rowLength, columnLength];
Ii = new double[rowLength];
dIi = new double[rowLength];
d2Ii = new double[rowLength];
for (int i = 0; i < rowLength; i++)
{
for (int j = 0; j < columnLength; j++)
{
pr0[i, j] = Math.Pow(dP[i, j], 2) / P[i, j];
pr1[i, j] = 2 * dP[i, j] * (d2P[i, j] / P[i, j]) - (Math.Pow(dP[i, j], 3) / Math.Pow(P[i, j], 2));
pr2[i, j] = (2 * Math.Pow(d2P[i, j], 2) + 2 * dP[i, j] * d3P[i, j]) / P[i, j] - 2 * Math.Pow(dP[i, j], 2) * (d2P[i, j] / -3) * dP[i, j] * (d2P[i, j] / Math.Pow(P[i, j], 2)) + 2 * (Math.Pow(dP[i, j], 4) / Math.Pow(P[i, j], 3));
}
}
Ii = RowColumn.rowSums(pr0);
dIi = RowColumn.rowSums(pr1);
d2Ii = RowColumn.rowSums(pr2);
#endregion
}
objIi.Add(Ii, dIi, d2Ii);
}
catch (Exception ex)
{
if (ex != null)
{
if (objIi == null)
{
objIi = new IiList();
}
objIi.Exception = ex.Message;
}
return(objIi);
}
return(objIi);
}
public static JiList Ji_Calc(double th, CATItems it, string model, double D)
{
JiList objJi = null;
double[] Ji = null; double[] dJi = null;
try
{
if (String.IsNullOrEmpty(model))
{
#region "Calculation for Dichotmous Items"
PiList pr = Pi.Pi_Calc(th, it, model, D);
if (pr == null)
{
objJi = new JiList();
objJi.Exception = "No Pi values found!";
return(objJi);
}
double[] P = pr.Pi; double[] dP = pr.dPi; double[] d2P = pr.d2Pi; double[] d3P = pr.d3Pi;
Ji = new double[dP.Length];
dJi = new double[d2P.Length];
objJi = new JiList(P.Length);
double[] Q = new double[P.Length];
for (int i = 0; i < P.Length; i++)
{
Q[i] = 1 - P[i];
}
for (int j = 0; j < Ji.Length; j++)
{
Ji[j] = dP[j] * d2P[j] / (P[j] * Q[j]);
}
for (int k = 0; k < dJi.Length; k++)
{
dJi[k] = (P[k] * Q[k] * (Math.Pow(d2P[k], 2) + dP[k] * d3P[k]) - Math.Pow(dP[k], 2) * d2P[k] * (Q[k] - P[k])) / (Math.Pow(P[k], 2) * Math.Pow(Q[k], 2));
}
#endregion
}
else
{
#region "Calculation for Polytomous Items"
PiListPoly pr = Pi.Pi_Poly_Calc(th, it, model, D);
if (pr == null)
{
objJi = new JiList();
objJi.Exception = "No Pi values found!";
return(objJi);
}
double[,] P = pr.Pi; double[,] dP = pr.dPi; double[,] d2P = pr.d2Pi; double[,] d3P = pr.d3Pi;
int rowLength = pr.Pi.GetLength(0);
int columnLength = pr.Pi.GetLength(1);
objJi = new JiList(rowLength);
double[,] prov = new double[rowLength, columnLength];
double[,] prov1 = new double[rowLength, columnLength];
Ji = new double[rowLength];
dJi = new double[rowLength];
for (int i = 0; i < rowLength; i++)
{
for (int j = 0; j < columnLength; j++)
{
prov[i, j] = dP[i, j] * d2P[i, j] / P[i, j];
prov1[i, j] = (P[i, j] * Math.Pow(d2P[i, j], 2) + P[i, j] * dP[i, j] * d3P[i, j] - Math.Pow(dP[i, j], 2) * d2P[i, j]) / Math.Pow(P[i, j], 2);
}
}
Ji = RowColumn.rowSums(prov);
dJi = RowColumn.rowSums(prov1);
#endregion
}
objJi.Add(Ji, dJi);
}
catch (Exception ex)
{
if (ex != null)
{
if (objJi == null)
{
objJi = new JiList();
}
objJi.Exception = ex.Message;
}
return(objJi);
}
return(objJi);
}