/// <summary>
/// Apply a derivative.
/// </summary>
/// <param name="value"></param>
/// <param name="index"></param>
/// <param name="derivative"></param>
public override void Apply(Func <double> value, int index, double derivative)
{
var result = new DoubleDerivatives();
// Specify actual value
if (value != null)
{
result[0] = value;
}
// Specify derivative
if (index > 0)
{
result[index] = () => derivative;
}
Result = result;
}
/// <summary>
/// Parse an expression.
/// </summary>
/// <param name="expression">The expression.</param>
/// <returns></returns>
Derivatives <Func <double> > IParser <Derivatives <Func <double> > > .Parse(string expression)
{
_stack.Clear();
ParseExpression(expression);
if (_stack.Count != 1)
{
throw new ParserException("Invalid expression", Input, Index);
}
var result = _stack.Pop();
// Compile all these expressions to funcs
var funcResult = new DoubleDerivatives(result.Count);
for (var i = 0; i < result.Count; i++)
{
if (result[i] != null)
{
funcResult[i] = Expression.Lambda <Func <double> >(result[i]).Compile();
}
}
return(funcResult);
}
/// <summary>
/// Divide derivatives.
/// </summary>
/// <param name="b">The other operand.</param>
/// <returns>
/// The divided result.
/// </returns>
public override Derivatives <Func <double> > Divide(Derivatives <Func <double> > b)
{
var size = Math.Max(Count, b.Count);
var result = new DoubleDerivatives(size);
var a0 = this[0];
var b0 = b[0];
result[0] = () => SafeDivide(a0(), b0());
for (var i = 1; i < size; i++)
{
var ai = this[i];
var bi = b[i];
if (ai != null && bi != null)
{
result[i] = () =>
{
var denom = b0();
return(SafeDivide(denom * ai() - a0() * bi(), denom * denom));
}
}
;
else if (ai != null)
{
result[i] = () => SafeDivide(ai(), b0());
}
else if (bi != null)
{
result[i] = () =>
{
var denom = b0();
return(-SafeDivide(a0() * bi(), denom * denom));
}
}
;
}
return(result);
}
/// <summary>
/// Subtract derivatives.
/// </summary>
/// <param name="b">The other operand.</param>
/// <returns>
/// The difference.
/// </returns>
public override Derivatives <Func <double> > Subtract(Derivatives <Func <double> > b)
{
var size = Math.Max(Count, b.Count);
var result = new DoubleDerivatives(size);
for (var i = 0; i < size; i++)
{
var arg1 = this[i];
var arg2 = b[i];
if (arg1 != null && arg2 != null)
{
result[i] = () => arg1() - arg2();
}
else if (arg1 != null)
{
result[i] = arg1;
}
else if (arg2 != null)
{
result[i] = () => - arg2();
}
}
return(result);
}
/// <summary>
/// Add derivatives.
/// </summary>
/// <param name="b">The other operand.</param>
/// <returns>
/// The sum.
/// </returns>
public override Derivatives <Func <double> > Add(Derivatives <Func <double> > b)
{
var size = Math.Max(Count, b.Count);
var result = new DoubleDerivatives(size);
for (var i = 0; i < size; i++)
{
var ai = this[i];
var bi = b[i];
if (ai != null && bi != null)
{
result[i] = () => ai() + bi();
}
else if (ai != null)
{
result[i] = ai;
}
else if (bi != null)
{
result[i] = bi;
}
}
return(result);
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="property">The property.</param>
public SimpleDerivativePropertyEventArgs(SpiceProperty property)
: base(property)
{
Result = null;
}
