Pc(2): out of bound 1 error

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Pc(2): out of bound 1 error

Bala Vignesh
I am trying to solve ODE equation inside a for loop for a given mdot, Ab and
time step. I am getting error .. can anyone help me please

Code:
rhop=1765;
a_burn=2.6292e-5;
n=0.33;
a=1577.1;
Ath=0.008167;
a=1577.1;
b=9e-7;
gamma=0.6465;
Vc=0.0943;
pc0=0;
%
%Read excel files
A=xlsread('Ignition transient.xlsx');
m=A(:,7);
tspan=A(:,4);
Area=A(:,6);
for i=2:40
  mdot=m(i)
  Ab=Area(i)
[t,Pc]= ode45(@(t,Pc)
(mdot+(rhop*Ab*a*Pc^n)-(Pc(i)*Ath/(a+(b*Pc))))*(gamma^2*(a+(b*Pc))^3/(Vc*(a-(b*Pc)))),
tspan, 0);
end

Error message:
error: Pc(2): out of bound 1
error: called from
    ignitionTransient>@<anonymous> at line 29 column 69
    starting_stepsize at line 46 column 5
    ode45 at line 192 column 25
    ignitionTransient at line 29 column 7



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Re: Pc(2): out of bound 1 error

Octave - General mailing list
On 1/13/20 8:54 AM, Bala Vignesh wrote:

> I am trying to solve ODE equation inside a for loop for a given mdot, Ab and
> time step. I am getting error .. can anyone help me please
>
> Code:
> rhop=1765;
> a_burn=2.6292e-5;
> n=0.33;
> a=1577.1;
> Ath=0.008167;
> a=1577.1;
> b=9e-7;
> gamma=0.6465;
> Vc=0.0943;
> pc0=0;
> %
> %Read excel files
> A=xlsread('Ignition transient.xlsx');
> m=A(:,7);
> tspan=A(:,4);
> Area=A(:,6);
> for i=2:40
>    mdot=m(i)
>    Ab=Area(i)
> [t,Pc]= ode45(@(t,Pc)
> (mdot+(rhop*Ab*a*Pc^n)-(Pc(i)*Ath/(a+(b*Pc))))*(gamma^2*(a+(b*Pc))^3/(Vc*(a-(b*Pc)))),
> tspan, 0);
> end
>
> Error message:
> error: Pc(2): out of bound 1
> error: called from
>      ignitionTransient>@<anonymous> at line 29 column 69
>      starting_stepsize at line 46 column 5
>      ode45 at line 192 column 25
>      ignitionTransient at line 29 column 7
>
On quick perusal, I don't see the definition of Pc, so maybe you just
need to initialize it to the correctly sized array.

In order to get further help, please try to minimize your example so
that it's self-contained (e.g. you (and I) can run it by pasting it into
a fresh instance of Octave).