C#•2y ago

❔ Need help making a chemical equation balancer in C#

Hi guys. As the title suggests, I need some help writing a chemical equation balancer in C#. To be exact, in Unity (the game engine). I need it for the project I'm making (a virtual lab) and I have no idea how to make it work. It seems to be immensely complex and I can't go forward without it. The algorithm must: 1) be compatible with the unity game engine, 2) be able to operate on any chemical equation, no matter the amount of reactants and products, 3) the input must be a string. Thanks in advance, Bin.

32 Replies

Klarth•2y ago

It's certainly not trivial given constraints 1 and 2.

youtubebinOP•2y ago

Well, I put these only as a precaution just in case

Klarth•2y ago

.NET is not particularly strong with math and Unity even less so.

youtubebinOP•2y ago

Well, I will be heading off now Goodnight

Google•2y ago

Why not just Simplex?

Klarth•2y ago

I'd do a quick look over https://python.plainenglish.io/balancing-chemical-equations-using-python-4b9086a92a7c for brute force or maybe something newer than https://www.sciencedirect.com/science/article/pii/S0895717706000367 if you really mean "any".

Google•2y ago

It all reduces to a simple integer programming problem.

youtubebinOP•2y ago

ok, seriously, I'm heading off to sleep Goodnight Hello again @JamesK.Polk So... Any ideas?

Google•2y ago

I already gave you my full idea.

youtubebinOP•2y ago

Fair enough

LPeter1997•2y ago

@JamesK.Polk Why the hell would you turn this into an IP problem, which by the way has nothing to do with Simplex, which is an LP solver

Google•2y ago

because it's simple

LPeter1997•2y ago

Balancing a chemical equation should be the same as balancing any equation IIRC. You can solve a system of linear equations, which is just a matter of Gauss-elimination

Google•2y ago

Sure, however you want to solve it is fine.

LPeter1997•2y ago

IP problem? Simple? Are you out of your mind

Google•2y ago

alglib.net non-commercial license could get it done quickly.

LPeter1997•2y ago

It's a famous NP-hard problem For something that can be done in linear time, it's a horrible recommendation

Google•2y ago

Direct your comments towards them, not me. Not really used to having language like this directed at me. I gave a recommendation, and it sounds like you have very strong feelings about it.

Google•2y ago

https://www.instructables.com/Balancing-Chemical-Equations-With-Spreadsheets/

Instructables

Balancing Chemical Equations With Spreadsheets

Balancing Chemical Equations With Spreadsheets: Balancing Chemical Equations with Spreadsheet Matrix Algebra Given the products and reactants of a chemical reaction, we want to find the stoichiometrically balanced equation for the reaction. This can be done with the matrix functions of a spread…

LPeter1997•2y ago

@Bin You can represent the problem as a series of linear equations that you can solve using Gauss-elimination. There's prolly linear algebra libs already out there, likely targeting ns 2.0 that you'll be able to use in Unity too I'm sorry for the strong language, it's nothing personal. I just hate when people seemingly talk out of their asses.

Google•2y ago

The solver used in that tutorial is Simplex. I've done this exact problem before in a few hours. I'm not sure where you get that I'm talking out my ass. I also just noted it could be reduced to IP problem if they cared about performance.

LPeter1997•2y ago

If they reduce it to an IP problem, it becomes slower

Google•2y ago

You could also go the LU decomposition route if you wanted.

LPeter1997•2y ago

IP solving is hard and way more inefficient than Gauss-elimination No need for matrix triangulation either, that's also way more complex than it has to be

Google•2y ago

That's right. There are many ways to skin this cat. I just provided my two cents. Sorry I did.

LPeter1997•2y ago

Then please, stop recommending horribly complex ways to incredibly simple problems

Google•2y ago

You can get both of those out of the box with existing Github links. The actual implementation doesn't need to be observed. Please don't tag me anymore just to do this. Focus on helping users, not flaming other users.

ero•2y ago

wait i remember this guy, they asked for help on this in the unity discord like many many months ago and refused to take any advice that would have made approaching this a million times easier

youtubebinOP•2y ago

key word: many many months ago

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

youtubebinOP•2y ago

Well I am working on it but uh something's wrong it *should( give me: [ [ 1, 0, 0, -2 ], [ 0, 2, -1, 0 ], [ 0, 4, 0, -3 ] ] instead some numbers are wrong it gives me [ [1, 0, -1, -2], [0, 2, -1, -1], [0, 4, -1, -3] ], I believe the issue lies somewhere here:

foreach (string molecule in righ)
            {
                int index = molecule.IndexOf(elem);
                if (index == -1) buildArr.Add(-1);
                else
                {
                    index += elem.Length;
                    Match numberAfterElement = Regex.Match(molecule.Substring(index), @"^\d+");
                    if (numberAfterElement == null || !numberAfterElement.Success)
                    {
                        buildArr.Add(-1);
                    }
                    else
                    {
                        buildArr.Add(-1 * Int32.Parse(numberAfterElement.Value));
                        string test = "";
                        foreach (var z in buildArr) test += $"{z}, ";
                        Debug.Log(test);
                    }
                }
            }
            rrefArray.Add(buildArr);

foreach (string molecule in righ)
            {
                int index = molecule.IndexOf(elem);
                if (index == -1) buildArr.Add(-1);
                else
                {
                    index += elem.Length;
                    Match numberAfterElement = Regex.Match(molecule.Substring(index), @"^\d+");
                    if (numberAfterElement == null || !numberAfterElement.Success)
                    {
                        buildArr.Add(-1);
                    }
                    else
                    {
                        buildArr.Add(-1 * Int32.Parse(numberAfterElement.Value));
                        string test = "";
                        foreach (var z in buildArr) test += $"{z}, ";
                        Debug.Log(test);
                    }
                }
            }
            rrefArray.Add(buildArr);

I simply can't find it (righ is an string array) elem is also a string

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Need help making a chemical equation balancer in C#