need help on implementing an algorithm

aliendesaster

Hi guys,

I have run into a problem implementing an simple algorithm to calculate the coefficients of chemic equation. The problem is actually as the title says I don´t know how to code this in php :evilgrin: .
I wrote already a parser for reaction-schemes,
so lets say we parsed
"KMnO4 + HCl --> MnCl2 + Cl2 + H2O + KCl"
(side a) --> (side b)
and know that we have O four times (O4) on side a on pos. 0 and Cl two times on side b on pos 0 and 1 for instance.
Of course the scheme is parsed into an array. I don´t think it is important to know the arraystructure I´ve chosen.
I would just like to get some hints on how to implement the following algorithm we can use to solve the equation:

We assume we can solve the equation using the coefficients abcdef like below:
a KMnO4 + b HCl --> c MnCl2 + d Cl2 + e H2O + f KCl

for K:
(1) a = f
for MG:
(2) a = c
for O:
(3) 4 a = e
for H:
(4) b = 2 e
for Cl:
(5) b = 2 c + 2 d + f
We just say a is 1, replace a with 1 and then have:
(1) 1 = f
(2) 1 = c
(3) 4 = e
(4) b = 2 e = 2 4 = 8
We use the calculated values below so we get:
(5) 8 = 2 + 2 d + 1
(5) 5 = 2 d
(5) 5
d = -
2
Now we almost got the final coefficients :
a = 1, b = 8, c = 1, d = 5/2, e = 4 und f = 1
We have to multiply all by 2 to get want we wanted:
a = 2, b = 16, c = 2, d = 5, e = 8 und f = 2

We replace the coefficients with the calculated values:
2 KMnO4 + 16 HCl --> 2 MnCl2 + 5 Cl2 + 8 H2O + 2 KCl

viola, solved!

So, is there any script you know which solves such equations.
If not, how could I implement the algorithm in php?
Well, maybe it´s a good idea to mention that I´m not that good in math heh.
Any help is greatly appreciated though. Note that this is a personal project 😉

drawmack

actually we do need the array structure because this is going to rely completely on array manipulation and we can't tell you how to manipulate something we don't know about.

I wrote a program that did this for my TI-82 but that was a couple of years ago, boy did it make chem 1 easy.

aliendesaster

Thank you for the reply drawmack. Well ok, here is it:

<?PHP
//Generell format of the array:
$ARR_Data=array();
$ARR_Data[0]=array();   //Everything from side a is here
$ARR_Data[1]=array();   //Everything from side b is here

//new "block" - a "block" is seperated by a plus (+). 
//In "KMnO4+HCl" "KMnO4" will be a "block" and "HCl" will be a "block"                                          

$ARR_Data[0][0]=array();
//New element. In block "KMnO4" K, Mn and O are elements for example...  

$ARR_Data[0][0][0]=array();
//New element defination:
$ARR_Data[0][0][0][0]="K";  //Element
$ARR_Data[0][0][0][1]=1;    //The number before an element - for example the two in "2Cl". If not defined it´s always 1!
$ARR_Data[0][0][0][2]=1;    //The number after an element - for instance H20 it´s the 2 of the H. If not defined - always 1! 
$ARR_Data[0][0][0][3]=0;    //Currently only used in special cases like Ca3(PO4)2. In this example instead of an 0 a 2 is saved at this position for the elements P and O. When not using any brackets it´s always 0.
//New element defination:                        

$ARR_Data[0][0][1][0]="Mn" //Mn(1) - 1 is omitted  

$ARR_Data[0][0][1][1]=1;    

$ARR_Data[0][0][1][2]=1;   

$ARR_Data[0][0][1][3]=0;    

//New element defination:                        

$ARR_Data[0][0][2][0]="O";  //O4 
$ARR_Data[0][0][2][1]=1;    

$ARR_Data[0][0][2][2]=4;   

$ARR_Data[0][0][2][3]=0;
//etc...

//For my already given example the array looks as follows (complete):

//In case you wonder, I didn´t type it all by hand. I wrote a small tool for that purpose :D
$ARR_Data[0][0]=array();
$ARR_Data[0][0][0]=array();
$ARR_Data[0][0][0][0]="K";
$ARR_Data[0][0][0][1]=1;
$ARR_Data[0][0][0][2]=1;
$ARR_Data[0][0][0][3]=0;
$ARR_Data[0][0][1]=array();
$ARR_Data[0][0][1][0]="Mn";
$ARR_Data[0][0][1][1]=1;
$ARR_Data[0][0][1][2]=1;
$ARR_Data[0][0][1][3]=0;
$ARR_Data[0][0][2]=array();
$ARR_Data[0][0][2][0]="O";
$ARR_Data[0][0][2][1]=1;
$ARR_Data[0][0][2][2]=4;
$ARR_Data[0][0][2][3]=0;
$ARR_Data[0][1]=array();
$ARR_Data[0][1][0]=array();
$ARR_Data[0][1][0][0]="H";
$ARR_Data[0][1][0][1]=1;
$ARR_Data[0][1][0][2]=1;
$ARR_Data[0][1][0][3]=0;
$ARR_Data[0][1][1]=array();
$ARR_Data[0][1][1][0]="Cl";
$ARR_Data[0][1][1][1]=1;
$ARR_Data[0][1][1][2]=1;
$ARR_Data[0][1][1][3]=0;
$ARR_Data[1]=array();
$ARR_Data[1][0]=array();
$ARR_Data[1][0][0]=array();
$ARR_Data[1][0][0][0]="Mn";
$ARR_Data[1][0][0][1]=1;
$ARR_Data[1][0][0][2]=1;
$ARR_Data[1][0][0][3]=0;
$ARR_Data[1][0][1]=array();
$ARR_Data[1][0][1][0]="Cl";
$ARR_Data[1][0][1][1]=1;
$ARR_Data[1][0][1][2]=2;
$ARR_Data[1][0][1][3]=0;
$ARR_Data[1][1]=array();
$ARR_Data[1][1][0]=array();
$ARR_Data[1][1][0][0]="Cl";
$ARR_Data[1][1][0][1]=1;
$ARR_Data[1][1][0][2]=2;
$ARR_Data[1][1][0][3]=0;
$ARR_Data[1][2]=array();
$ARR_Data[1][2][0]=array();
$ARR_Data[1][2][0][0]="H";
$ARR_Data[1][2][0][1]=1;
$ARR_Data[1][2][0][2]=2;
$ARR_Data[1][2][0][3]=0;
$ARR_Data[1][2][1]=array();
$ARR_Data[1][2][1][0]="O";
$ARR_Data[1][2][1][1]=1;
$ARR_Data[1][2][1][2]=1;
$ARR_Data[1][2][1][3]=0;
$ARR_Data[1][3]=array();
$ARR_Data[1][3][0]=array();
$ARR_Data[1][3][0][0]="K";
$ARR_Data[1][3][0][1]=1;
$ARR_Data[1][3][0][2]=1;
$ARR_Data[1][3][0][3]=0;
$ARR_Data[1][3][1]=array();
$ARR_Data[1][3][1][0]="Cl";
$ARR_Data[1][3][1][1]=1;
$ARR_Data[1][3][1][2]=1;
$ARR_Data[1][3][1][3]=0;

I first didn´t want to post it because now it got complicated:bemused: I hope someone is gonna reply. Well, I can change whatever you want, so if you think you know a better way to store it please tell me! Well, the best input format depends on the exact implementation of the algorithm, so...