Fuctions: Multiple inputs & outputs with if statements

Hello,

I'm an amatuer user of Matlab and I'm looking to enhance my knowledge of coding.

I've written a code in the past to calculate relative permeabilty using functions.

I had a separate function file for water, and another for oil both involving if/elseif/else statements.

I'm trying to make my code more efficient and combine both functions into one function with multiple inputs/outputs.

But I'm not getting the same answer that I'm expecting and getting with seperate function files. Why is that? and how can I resolve it?

Thanking you in advance.

Code for Oil Relative Permeability:

function kro = rel_perm_oil(So,Swr,Sor,no,krostar)
% Calculation of Oil Relative Permeability
if So <= Sor
    kro = 0;
elseif So >= 1 - Swr
    kro = krostar;
else
    kro = krostar*(((So-Sor)/(1-Sor-Swr))^no);
end

Code for Water Relative Permeability:

function krw = rel_perm_wat(Sw,Swr,Sor,nw,krwstar)
% Calculation of Water Relative Permeability
if Sw <= Swr
    krw = 0;
elseif Sw >= 1-Sor
    krw = krwstar;
else
    krw = krwstar*(((Sw-Swr)/(1-Sor-Swr))^nw);
end

Combined code for both oil & water permeabilities:

function [krw,kro] = rel_perm(Sw,So,Swr,Sor,nw,no,krwstar,krostar)
% Calculation of Relative Permeability

% Water Relative Permeability
if Sw <= Swr
    krw = 0;
elseif Sw >= 1-Sor
    krw = krwstar;
 else
    krw = krwstar*(((Sw-Swr)/(1-Sor-Swr))^nw);
 end

% Oil Relative Permeability
if So <= Sor
    kro = 0;
elseif So >= 1 - Swr
    kro = krostar;
else
    kro = krostar*(((So-Sor)/(1-Sor-Swr))^no);
end

Answer 1

[Matt J]

No reason at all. And I don't see any disagreement:

K>> [krw,kro] = rel_perm(1,1,1,1,1,1,1,1)

krw =

     0


kro =

     0

K>>  krw = rel_perm_wat(1,1,1,1,1)

krw =

     0

K>> kro = rel_perm_oil(1,1,1,1,1)

kro =

     0

Solved!!

[Mizo Amreya]

You're right. I should get the same values.

Turns out the problem I had was with calling the function in my code.

Thank you for your effort.