stdLambda #performance

[ws-garcia]

I have been playing with stdLambda and a doubt is gnawing my head. Why is the evaluation of a function like sin(x) so slow compared to numeric evaluation in this class module, given the fact it is a single operation?

[sancarn]

It's difficult to say for sure, it could be due to a number of reasons. Happy for help looking into exactly why. The relevant parts of the code are as follows:

1. Function symbol
2. Getting args off the stack
3. Function evaluation

Some whatchouts:

• Could be due to how much mem copying is going on, to prepare arguments etc.
• If you've added any overrides in oFuncExt that'd be why, as there is a check that sin is overwritten in the late-bound dictionary:

---

    If TypeName(Me.oFunctExt) = "Dictionary" Then
        If Me.oFunctExt.exists(sFuncName) Then
            Dim vInjectedVar As Variant
            Call CopyVariant(vInjectedVar, oFunctExt(sFuncName))
            If TypeOf vInjectedVar Is stdICallable Then
                Call CopyVariant(evaluateFunc, Me.oFunctExt(sFuncName).RunEx(args))
            Else
                Call CopyVariant(evaluateFunc, vInjectedVar)
            End If
            Exit Function
        End If
    End If

so that's where i'd check first

In general though it's likely because at min-3 stack pops are required (Func symbol, argLength, arg + timeWhileEvaluating); where with standard numerical evaluation only 1 stack pop is required (arg).

[sancarn]

I've included this on the stdLambda performance megathread here:
#49 (comment)

Please use this issue in future.