# how could i use the while statement more faster

Asked by ahmed hattab on 21 Jul 2012
Latest activity Commented on by ahmed hattab on 21 Jul 2012

if any one please could help me with this. I'm making a loop using while statement , but it took too much time. is there is any way to reduce the needed time ?

## 1 Comment

Jan Simon on 21 Jul 2012

It is impossible to suggest an improvement without seeing the code. Please add it to the question by editing.

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Answer by George Papazafeiropoulos on 21 Jul 2012

What do you want to do exactly inside this while loop? Can you show some piece of code?

ahmed hattab on 21 Jul 2012

well with this code i'm tryinf to find the solution of 2 equations in 2 variaples

the first equation is Mcc+Mct+Ms-M= 0 the seconed one Cc-Cct-Ts=0

the first variple is eps and the second one is x

i know there is a way to solve equations directly in matlap but these equations are a little complicated so when i try to solve them they give no ansewer.I try to do that using "solve" and "fmin" both of them fails to find the solution so i tried numirically. What is starnge that the same code i made in VBA and it works very fast, i don't know whay Matlab take so much time

here is the code

ep1=0;

ep2=epult;

eps=(ep1+ep2)/2;

x1 = 0;

x2 =h;

x = (x1+x2)/2;

run('C:\hattab\hattab\master of scince\my master\matlab\using matricies\Force.m');

while abs(Mcc+Mcct+Ms-M)/M>eqTol

` if Mcc+Ms+Mcct-M>0 `
`        ep1=ep1;`
`        ep2=eps;`
`        eps=(ep1+ep2)/2;`
`    else`
`        ep1=eps;`
`        ep2=ep2;`
`        eps=(ep1+ep2)/2;`
`    end`
```        x1 = 0;
x2 =h;
x = (x1+x2)/2;
run('C:\hattab\hattab\master of scince\my master\matlab\using matricies\Force.m');
while abs(Cc-Ts-Cct)/Cc >eqTol
if Cc-Ts-Cct>0
x1=x1;
x2=x;
x=(x1+x2)/2;
% clac force
run('C:\hattab\hattab\master of scince\my master\matlab\using matricies\Force.m');
else
x2=x2;
x1=x;
x=(x1+x2)/2;
% clac force
run('C:\hattab\hattab\master of scince\my master\matlab\using matricies\Force.m');
end
end```

end

Jan Simon on 21 Jul 2012

Do not overwrite the built-in function eps with a local variable.

Add the folder "C:\hattab\hattab\master of scince\my master\matlab\using matricies\" to the path (see e.g. addpath) and call the script Force directly without the run command. It would even better to convert Force to a function.

ahmed hattab on 21 Jul 2012

it works thanks very much for your help