double Rectangle(ExpressionParameters parameters)
{
if (parameters == null)
parameters = new ExpressionParameters ();
var result = 0.0M;
var left = (decimal)(double)this.Left.Calculate (parameters);
var right = (decimal)(double)this.Right.Calculate (parameters);
if (right <= left)
throw new InvalidOperationException ("Invalid Intergral-Bounds");
var n = 1000; // number of rectangles
var dx = (right - left) / (decimal)n;
var param = default(Parameter);
foreach (var p in parameters.Parameters.Collection) {
if (p.Key == this.Variable.Name) {
param = p;
break;
}
}
if (param == null) {
param = new Parameter (
this.Variable.Name, 0, ParameterType.Normal);
parameters.Parameters.Add (param);
}
for (var x = left; x <= right; x += dx) {
param.Value = (double)x;
var z = (double)this.Body.Calculate (parameters);
result += (dx * (decimal)z);
}
return (double)result;
}
double Simpson(ExpressionParameters parameters)
{
if (parameters == null)
parameters = new ExpressionParameters ();
var a = (double)this.Left.Calculate (parameters);
var b = (double)this.Right.Calculate (parameters);
if (b <= a)
throw new InvalidOperationException ("Invalid Intergral-Bounds");
var n = 10000; // number of rectangles
var h = (b - a) / (double)n;
var param = default(Parameter);
foreach (var p in parameters.Parameters.Collection) {
if (p.Key == this.Variable.Name) {
param = p;
break;
}
}
if (param == null) {
param = new Parameter (
this.Variable.Name, 0, ParameterType.Normal);
parameters.Parameters.Add (param);
}
var sum = 0.0;
for (var i = 1; i <= n - 3; i = i + 2) {
param.Value = a + i * h;
sum += (double)this.Body.Calculate (parameters);
}
param.Value = a + (n - 1) * h;
sum += (double)this.Body.Calculate (parameters);
sum *= 4;
var sum2 = 0.0;
for (var i = 2; i <= n - 4; i += 2) {
param.Value = a + i * h;
sum2 += (double)this.Body.Calculate (parameters);
}
param.Value = a + (n - 2) * h;
sum2 += (double)this.Body.Calculate (parameters);
sum2 *= 2;
sum += sum2;
param.Value = a;
sum += (double)this.Body.Calculate (parameters);
param.Value = b;
sum += (double)this.Body.Calculate (parameters);
return Math.Round ( h / 3 * sum, 5 );
}
public VariableViewModel(Parameter parameter)
{
this.parameter = parameter;
}
