private void SetResult(EvaluationContext context, FunctionFoundEventArgs <Derivatives <Func <double> > > args, IFunction <double, double> doubleFunction)
{
var argumentCount = args.ArgumentCount;
var variableCount = 1;
for (var i = 0; i < argumentCount; i++)
{
variableCount = Math.Max(variableCount, args[i].Count);
}
var result = new DoubleDerivatives(variableCount);
var arguments = new Func <double> [argumentCount];
for (var i = 0; i < argumentCount; i++)
{
var iLocal = i;
arguments[i] = () => args[iLocal][0]();
}
result[0] = () =>
{
var argumentValues = arguments.Select(arg => arg()).ToArray();
return(doubleFunction.Logic(string.Empty, argumentValues, context));
};
if (doubleFunction is IDerivativeFunction <double, double> derivativeFunction)
{
var derivatives = new Lazy <Derivatives <Func <double> > >(() => derivativeFunction.Derivative(string.Empty, args, context));
for (var i = 1; i <= variableCount; i++)
{
var derivativeIndex = i;
if (IsDerivativeDefined(args, derivativeIndex))
{
result[i] = () => GetDerivativeValue(args, derivativeIndex, argumentCount, derivatives);
}
}
}
args.Result = result;
}
/// <summary>
/// Exponentials
/// </summary>
public static Derivatives <Func <double> > ApplyExp(Derivatives <Func <double> >[] arguments)
{
arguments.ThrowIfNot(nameof(arguments), 1);
var arg = arguments[0];
var result = new DoubleDerivatives(arg.Count);
var a0 = arg[0];
result[0] = () => Math.Exp(a0());
// Chain rule for derivatives
for (var i = 1; i < arg.Count; i++)
{
if (arg[i] != null)
{
var ai = arg[i];
result[i] = () => Math.Exp(a0()) * ai();
}
}
return(result);
}
/// <summary>
/// Applies the square root.
/// </summary>
/// <param name="arguments">The arguments.</param>
/// <returns>The square root result.</returns>
public static Derivatives <Func <double> > ApplySqrt(Derivatives <Func <double> >[] arguments)
{
arguments.ThrowIfNot(nameof(arguments), 1);
var a = arguments[0];
var result = new DoubleDerivatives(a.Count);
var a0 = a[0];
result[0] = () => Math.Sqrt(a0());
// Apply the chain rule
for (var i = 1; i < a.Count; i++)
{
if (a[i] != null)
{
var ai = a[i];
result[i] = () => - 0.5 * ai() / Math.Sqrt(a0());
}
}
return(result);
}
/// <summary>
/// Applies the absolute value.
/// </summary>
/// <param name="arguments">The arguments.</param>
/// <returns>The absolute value result.</returns>
public static Derivatives <Func <double> > ApplyAbs(Derivatives <Func <double> >[] arguments)
{
arguments.ThrowIfNot(nameof(arguments), 1);
var arg = arguments[0];
var result = new DoubleDerivatives(arg.Count);
var a0 = arg[0];
result[0] = () => Math.Abs(a0());
// Apply chain rule
for (var i = 1; i < arg.Count; i++)
{
if (arg[i] != null)
{
var ai = arg[i];
result[i] = () =>
{
var tmp = a0();
return(tmp > 0 ? ai() : tmp < 0 ? -ai() : 0);
};
}
}
return(result);
}
/// <summary>
/// Applies the arctangent.
/// </summary>
/// <param name="arguments">The arguments.</param>
/// <returns>The arctangent result.</returns>
public static Derivatives <Func <double> > ApplyAtan(Derivatives <Func <double> >[] arguments)
{
arguments.ThrowIfNot(nameof(arguments), 1);
var arg = arguments[0];
var result = new DoubleDerivatives(arg.Count);
var a0 = arg[0];
result[0] = () => Math.Atan(a0());
// Apply the chain rule
for (var i = 1; i < arg.Count; i++)
{
if (arg[i] != null)
{
var ai = arg[i];
result[i] = () =>
{
var x = a0();
return(ai() / (1 + x * x));
};
}
}
return(result);
}
/// <summary>
/// Logarithms
/// </summary>
public static Derivatives <Func <double> > ApplyLog(Derivatives <Func <double> >[] arguments)
{
arguments.ThrowIfEmpty(nameof(arguments));
if (arguments.Length == 1)
{
// Ln(f(x))' = 1/f(x)*f'(x)
var arg = arguments[0];
var result = new DoubleDerivatives(arg.Count);
var a0 = arg[0];
result[0] = () => Math.Log(a0());
// Chain rule
for (var i = 1; i < arg.Count; i++)
{
if (arg[i] != null)
{
var ai = arg[i];
result[i] = () => ai() / a0();
}
}
return(result);
}
if (arguments.Length == 2)
{
// Log(g(x), f(x)) = Ln(g(x)) / Ln(f(x))
var g = arguments[0];
var f = arguments[1];
var size = Math.Max(f.Count, g.Count);
var result = new DoubleDerivatives(size);
var g0 = g[0];
var f0 = f[0];
result[0] = () => Math.Log(g0(), f0());
// Chain rule
for (var i = 1; i < size; i++)
{
if (g[i] != null && f[i] != null)
{
var gi = g[i];
var fi = f[i];
result[i] = () =>
{
var tmpf0 = f0();
var tmpg0 = g0();
return(gi() / tmpg0 / Math.Log(tmpf0) - fi() / tmpf0 * Math.Log(tmpg0, tmpf0));
};
}
else if (g[i] != null)
{
var gi = g[i];
result[i] = () => gi() / g0() / Math.Log(f0());
}
else if (f[i] != null)
{
var fi = f[i];
result[i] = () =>
{
var tmpf0 = f0();
return(-fi() / f0() * Math.Log(g0(), tmpf0));
};
}
}
return(result);
}
throw new CircuitException("Invalid number of arguments, {0} given but 2 expected".FormatString(arguments.Length));
}
/// <summary>
/// Applies the maximum operator.
/// </summary>
/// <param name="arguments">The arguments.</param>
/// <returns>The maximum result.</returns>
public static Derivatives <Func <double> > ApplyMax(Derivatives <Func <double> >[] arguments)
{
arguments.ThrowIfEmpty(nameof(arguments));
var size = 1;
for (var i = 0; i < arguments.Length; i++)
{
size = Math.Max(size, arguments[i].Count);
}
var result = new DoubleDerivatives(size);
if (arguments.Length == 1)
{
result[0] = arguments[0][0];
return(result);
}
{
// First two arguments
var a = arguments[0][0];
var b = arguments[1][0];
result[0] = () => Math.Max(a(), b());
for (var k = 1; k < size; k++)
{
if (arguments[0][k] != null || arguments[1][k] != null)
{
CircuitWarning.Warning(null, "Trying to derive Min() for which the derivative may not exist in some points");
var tmpda = arguments[0][k];
var tmpdb = arguments[1][k];
var funca = arguments[0][0];
var funcb = arguments[1][0];
if (tmpda != null && tmpdb != null)
{
result[k] = () => funca() > funcb() ? tmpda() : tmpdb(); // Use the derivative of the function that is currently the smallest
}
else if (tmpda != null)
{
result[k] = () => funca() > funcb() ? tmpda() : 0;
}
else if (tmpdb != null)
{
result[k] = () => funca() > funcb() ? 0 : tmpdb();
}
}
}
}
for (var i = 2; i < arguments.Length; i++)
{
// First two arguments
var a = result[0];
var b = arguments[i][0];
result[0] = () => Math.Max(a(), b());
for (var k = 1; k < size; k++)
{
if (arguments[0][k] != null || arguments[1][k] != null)
{
CircuitWarning.Warning(null, "Trying to derive Min() for which the derivative may not exist in some points");
var tmpda = result[k];
var tmpdb = arguments[i][k];
var funca = a;
var funcb = arguments[i][0];
if (tmpda != null && tmpdb != null)
{
result[k] = () => funca() > funcb() ? tmpda() : tmpdb(); // Use the derivative of the function that is currently the smallest
}
else if (tmpda != null)
{
result[k] = () => funca() > funcb() ? tmpda() : 0;
}
else if (tmpdb != null)
{
result[k] = () => funca() > funcb() ? 0 : tmpdb();
}
}
}
}
return(result);
}
