Multiple Inputs, Multiple Outputs

I have the following code:

f=@rate;

Y0 = [40; 125; 100; 250; 1500; 300; 0; 2; 0.5; 30; 8; 10; 10];

function output=rate(Y0)
 
%Y0 = [SI; SS; XI ; XS; XB_H ; XB_A ; XP; SO; SNO ; SNH ;SND ; XND ; S_ALK ];
 
%Y0 = [40; 125; 100; 250; 1500; 300; 0; 2; 0.5; 30; 8; 10; 10];
 
%j=Process
%i= component
 
 
%SI=40;
%SS=125;
%XI=100;
%XS=250;
%XB_H=1500;
%XB_A=300;
%XP=0;
%SO=2;
%SNO=0.5;
%SNH=30;
%SND=8;
%XND=10;
%S_ALK=10;
 
%%Process rate expression constants at 20C
mu_H=6; %1/day
mu_A=0.8; %1/day
KS=20; %gCOD/m^3
KNH=1; %gNH2-N/m^3
K_OH=0.2; %gO2/m^3
K_OA=0.4; %gO2/m^3
KNO=0.5; %gNO3-N/m^3
ng=0.8; %dimensionless
bH=0.62; %1/day
bA=0.2; %1/day
ka=0.08; %m^3*COD(g*day)^-1
kH=3; %g slowly biodegradable COD (g cell COD*day)^-1
KX=0.03; %g slowly biodegradable COD(g cell COD)^-1
nH=0.4; %dimensionless
 
%%Constants for coefficients at 20C
YH=0.67; %g cell COD formed (g N oxidized)^-1
iXB=0.086; %g N(g COD)^-1) in biomass
iXP=0.06; %g N(g COD)^-1 in endogenous mass
YA=0.24; %g cell COD formed (g N oxidized)^-1
fp=0.08; %dimensionless
 
 
P1= (mu_H)*(SS/(KS+SS))*(SO/(K_OH+SO))*(XB_H);
P2= (mu_H)*(SS/(KS+SS))*(K_OH/(K_OH+SO))*(SNO/(KNO+SNO))*(ng*XB_H);
P3= (mu_A)*(SNH/(KNH+SNH))*(SO/(K_OA+SO))*(XB_A);
P4= (bH)*(XB_H);
P5= (bA)*(XB_A);
P6= (ka)*(SND)*(XB_H);
P7= (kH)*((XS/XB_H)/((KX)+(XS/XB_H)))*((SO/(K_OH+SO))+(nH)*(K_OH/(K_OH+SO))*(SNO/(KNO+SNO)))*(XB_H);
P8= P7*(XND/XS);
 
%r_SI=0; 
%r_SS=((-1/YH)*P1)+((-1/YH)*P2)+(1*P7);
%r_XI=0; 
%r_XS=((1-fp)*P4)+((1-fp)*P5)+(-1*P7);
%r_XB_H=(1*P1)+(1*P2)+(-1*P4); 
%r_XB_A=(1*P3)+(-1*P5);
%r_XP=((fp)*(P4))+((fp)*(P5));
%r_SO=((-((1-YH)/(YH)))*P1)+((-((4.57-YA)/(YA)))*P3);
%r_SNO=((-((1-YH)/(2.86*YH)))*P2)+((1/YA)*P3);
%r_SNH=((-1*iXB)*(P1))+((-1*iXB)*(P2))+((-iXB-(1/YA))*P3)+(P6);
%r_SND=(-1*P6)+(P8);
%r_XND=((iXB-(fp*iXP))*(P4))+((iXB-(fp*iXP))*(P5))+(-1*P8);
%r_S_ALK=(((-iXB/14))*(P1))+((((1-YH)/(14*(2.86*YH)))-(iXB/14))*(P2))+((((-iXB/14))-(1/(7*YA)))*(P3))+((1/14)*(P6));
 
output=[0; 
((-1/YH)*P1)+((-1/YH)*P2)+(1*P7);
0; 
((1-fp)*P4)+((1-fp)*P5)+(-1*P7);
(1*P1)+(1*P2)+(-1*P4); 
(1*P3)+(-1*P5);
((fp)*(P4))+((fp)*(P5));
((-((1-YH)/(YH)))*P1)+((-((4.57-YA)/(YA)))*P3);
((-((1-YH)/(2.86*YH)))*P2)+((1/YA)*P3);
((-1*iXB)*(P1))+((-1*iXB)*(P2))+((-iXB-(1/YA))*P3)+(P6);
(-1*P6)+(P8);
((iXB-(fp*iXP))*(P4))+((iXB-(fp*iXP))*(P5))+(-1*P8);
((-(iXB/14))*P1)+(((1-YH)/(14*(2.86*YH))-(iXB/14))*P2)+(((-(iXB/14))-(1/7*YA))*P3)+((1/14)*P6)];
 
end

All I want to do is input any column vector of 13 numerical values, have each of them be inputted in their respective equation, and I want MATLAB to tell me what the output values are. How do I do this? Thanks in advance.

Answer 1

[Mehmed Saad]

This is not a good coding approach

SI=Y0(1);
SS=Y0(2);
XI=Y0(3);
XS=Y0(4);
XB_H=Y0(5);
XB_A=Y0(6);
XP=Y0(7);
SO=Y0(8);
SNO=Y0(9);
SNH=Y0(10);
SND=Y0(11);
XND=Y0(12);
S_ALK=Y0(13);

or you can insert this in the start of function

tx={'SI'; 'SS'; 'XI' ; 'XS'; 'XB_H' ; 'XB_A' ; 'XP'; 'SO'; 'SNO' ; 'SNH' ;'SND' ; 'XND' ; 'S_ALK'};
for i=1:length(Y0)
    feval(@()assignin('caller',tx{i},Y0(i)));
end

[JR]

Thanks a ton!!

[Stephen23]

"This is not a good coding approach"

Note that writing out these lines

SI=Y0(1);
SS=Y0(2);
XI=Y0(3);
XS=Y0(4);
XB_H=Y0(5);
XB_A=Y0(6);
XP=Y0(7);
SO=Y0(8);
SNO=Y0(9);
SNH=Y0(10);
SND=Y0(11);
XND=Y0(12);
S_ALK=Y0(13);

will be faster, more efficient, and easier to debug than calling feval and assignin. That would be the better choice.

[Mehmed Saad]

@Stephen Cobeldic sir i mean both of them

good coding approach is to directly use variable Y

[Ameer Hamza]

"good coding approach is to directly use variable Y"

Not always. Good coding approach is the one that makes your code easy to understand and debug. For example, If the OP is trying to implement a system of mathematical equations. It can be much more important to use consistent notation, then using an array. For example, consider following two codes. I am sure the first code is much more readable and easy to debug as compared to the second code.

Using the individual variable name:

eq1 = alpha + beta^3 + gamma/2 + eta;
eq2 = log(gamma) + sqrt(eta) + sin(alpha);
eq3 = exp(eta) - beta;

Using array:

eq1 = y(1) + y(2)^3 + y(3)/2 + y(4);
eq2 = log(y(3)) + sqrt(y(4)) + sin(y(1));
eq3 = exp(y(4)) - y(2);

[Mehmed Saad]

agreed

Thanks a lot sir

Answer 2

[Ameer Hamza]

Create a file named rate.m and save the code of function in that file. The code of the function includes the lines between

function output=rate(Y0)
    % function code
end

inside the function, uncomment these lines and write them like this

SI=Y0(1);
SS=Y0(2);
XI=Y0(3);
XS=Y0(4);
XB_H=Y0(5);
XB_A=Y0(6);
XP=Y0(7);
SO=Y0(8);
SNO=Y0(9);
SNH=Y0(10);
SND=Y0(11);
XND=Y0(12);
S_ALK=Y0(13);

Then call the function like this

Y0 = [40; 125; 100; 250; 1500; 300; 0; 2; 0.5; 30; 8; 10; 10];
out = rate(Y0);

[JR]

Thank you so much. Your way worked as well as the individual above.