Greetings,

I just wanted to let people know that the Alvaro's ｢Evals()｣ function does not work numerically; it only works as a symbolic evaluation (ie., Optimization = ☑ Symbolic). As such, it cannot be used for numerical evaluations down the line.

Regardless of the limitations, I am quite impressed by this bit of handiwork.

- Kenny Lemens, P.E. ᵂᴵ

Version with uncertainties calculations added.



EvalsWithErr.sm (91kb) downloaded 50 time(s).

EvalsWithErr.pdf (216kb) downloaded 23 time(s).

Best regards.
Alvaro.

Hi. This could be a first approach.



EvalsWithErr with modifications.sm (101kb) downloaded 52 time(s).
EvalsWithErr with modifications.pdf (284kb) downloaded 32 time(s).

Best regards.
Alvaro

So I honestly think the original input was fine. Defining variables in a mathcad window is a bit annoying.
The only change I think is needed, but seems to be very hard or impossible, it to define the variables, used in the formula, outside of the evals function.
The best I can come up with requires you to define a second time what units are used for each variable used.

As you can see the variables are defined as any other variable in a calculation sheet and can be used in other formulas.
There is a vector that lists the units for each variable again. This is used to remove the unit when used in the Evals() function.
It seems like there is no way to do this without manually specifying the unit because there is no way to convert the variable exactly as defined into a string, you need to divide out the unit to keep the same numerical value. So there is no way to take the b:=17.3 lb and convert that definition into a string exactly as I show it. It would be nice if this was automatic, but I don't this is possible with how SMath is programed.

A note is that the first step in the substitution seems to reduce the units automatically. It would be nice to just show the initial substitution without any simplification or elimination of units in this first step.

I also changed the way the final unit is shown, so that it matches the blue color of other units.

Since in a table region you can display units in blue using "S:'" before the unit text.

Evals v2-N.sm (29kb) downloaded 26 time(s).

Hi Alvaro,

I've been looking into this concept again and I was hoping you could help me with some ideas/issues.

As it seems, the equation written within the Evals() function has to be with a,b,c.. or m1,m2,m3.. so alphabetical or numerical order, and this order matches the order of the listed values within Evals() as well.


There seems to a couple of issues with the order in which values are shown in the original equation vs. the later substitution steps, as well as how the units are shown for the substitution.

So here is what I envision as working well.

We can list variables as we normally do, and they can have any variable name, not just a,b,c or m1,m2,m3.
The Evals() function will require to specify the formula with the same variables you previously listed. Maybe listing the formula and the variables is enough and we don't need to list the variables again?
Then you need to specify how many decimal places you need, but it would be nice to not have trailing zeros so that substituted values look the same as previously listed.
Then we can specify the final unit we want for the result.

We don't need to show any steps and the substitution can be only a visual, the evaluation can be done like normal in the background and simply assigned to the variable listed.


Do you think something like this can be possible?

Hi Alvaro,

That is a start, but I still have some questions/clarifications.

Is there no way to define the variables outside of the MathCAD region?
In the original Evals(), both the question and the output unit were defined within the Evals() function, this is fine.

Any way to just show the unit after each value instead of showing the units grouped together?
In ne we have lb outside parenthesis, and in the other it is showing m^2 instead of two m units.

Also, is the order not controllable? We specified 2c+b+a, but get b+a+2c.

Sadly, this is the main issue.

Everything is fine for default units, but if anything is not in default, it is immediately converted, and the value as displayed is lost.



There seems to be no way other than the MathCAD region to do this at the moment.

By the way, I made a new post showing a manual way to achieve this that is probably as much if not less work that what is already required for your Evals(s) function.

For now, I think that the manual method is as good as it gets until there is a change within SMath.

Andrey said he was going to try and prioritize it, but that was a while back.
I think there are a lot of people who want this and are willing to contribute financially to make this happen. Maybe we need to do a crowd funding round?

This is better, actually not bad at all.
Can you make it so that the formula is input directly into Ev() along with the output unit?
That way eq only contains the variables, since this part won't be hidden.
The Ev() function will be hidden in a table region to clean it up nice.



Also, any way to get 500 up on top next to unit?

Edited by user 26 May 2024 18:35:11(UTC)  | Reason: Not specified

Hi. I don't see how to do that, without Mathcad solve block to prevent the evaluation of the arguments of the function. This is what the function F gets as arguments



Best regards.
Alvaro.

I guess the formatting problem can be solved by applying curly braces (they seem to never harm) in the string representation.