/// <inheritdoc/>
public bool TryCompile(IReadOnlyList <MathExpression> arguments, ICompilationContext <object?> context, ITypeHintHandler typeHintHandler, [MaybeNullWhen(false)] out Expression expr)
{
if (arguments.Count != 1)
{
expr = null;
return(false);
}
var argExpr = context.Transform(arguments.First());
if (argExpr.Type == typeof(float) || argExpr.Type == typeof(double))
{ // if this is a floating point
var method = Helpers.GetMethod <Action <double> >(d => Math.Log(d)) !;
expr = Expression.Call(method, CompilerHelpers.ConvertToType(argExpr, typeof(double)));
return(true);
}
else if (CompilerHelpers.IsFloating(argExpr.Type) || CompilerHelpers.IsIntegral(argExpr.Type))
{ // if this is a built-in integer or decimal
var method = Helpers.GetMethod <Action <decimal> >(d => DecimalMath.Ln(d)) !;
expr = Expression.Call(method, CompilerHelpers.ConvertToType(argExpr, typeof(decimal)));
return(true);
}
expr = null;
return(false);
}
public void NaturalLog(decimal arg, decimal expect, decimal error)
{
var actual = DecimalMath.Ln(arg);
var actualError = Math.Abs(expect - actual);
Assert.True(error >= actualError, $"Error of {actualError}, expected no more than error of {error}");
}
/// <inheritdoc/>
public override MathExpression ApplyTo(FunctionExpression expr, IOptimizationContext <object?> ctx, out bool transformResult)
{
if (!expr.IsUserDefined && (expr.Name == BuiltinFunctionExp.ConstName || expr.Name == BuiltinFunctionLn.ConstName))
{ // exp(x)
if (expr.Arguments.Count == 1)
{
var arg = ApplyTo(expr.Arguments.First(), ctx);
if (arg is LiteralExpression lit)
{
transformResult = true;
if (expr.Name == BuiltinFunctionExp.ConstName)
{
return(new LiteralExpression(DecimalMath.Exp(lit.Value)).WithToken(expr.Token));
}
if (expr.Name == BuiltinFunctionLn.ConstName)
{
return(new LiteralExpression(DecimalMath.Ln(lit.Value)).WithToken(expr.Token));
}
}
}
}
return(base.ApplyTo(expr, ctx, out transformResult));
}
public void NaturalLogThrow(decimal arg) => Assert.Throws <OverflowException>(() => DecimalMath.Ln(arg));
