sjoelund.se,
 
   thank you for your answer,

   In fact, I would like to assign a value for the initial temperature for each iteration, knowing that these values are saved in an array.

  So I want the Tint takes a new value from the array for each iteration, in order to solve an ODE.



HOOOOPING that I have described the problem correctly and you have understood my question.

thanks

model temperartureModel



parameter Real Tint=17.5;

Real T(start=Tint);



parameter Real [6,9] data={{22.3,    26.6,    27.7,    30.7,    29.8,    31.3,    19.5,    539,    0.3},

{26.5,    27.7,    29.3,    27.9,    29.8,    31.3,    19.6,    535,    0.8},

{26.9,    27.7,    28.1,    29.3,    29.9,    31.3,    19.7,    478,    1.6},

{27.3,    28.5,    28.3,    29.6,    29.9,    31.4,    19.7,    482,    2.3},

{27.3,    28.0,    28.0,    29.5,    29.8,    31.4,    19.7,    500,    2.5},

{27.4,    28.1,    28.6,    29.6,    29.8,    31.3,    19.8,    548,    2.5}};

//



/*

other parameters





*/

equation

for i in 1: N_mesure loop



der(T) = (q_punto_r_g_sky + q_r_g_gr * (Ta - T) + q_conv_g * (Ta - T) - q_cd_g_pv * (T - Tint) + alfa_fg * G * Ag) * (1 / Cg);



// others equations 

end for



end temperartureModel;

When you write:

Real T(start=T0, fixed=true);

It means that T has start value T0 at initialization. You cannot change that T0 in a for loop. If you have a for lopp in an algorithm or equation section that cannot affect the initialization anymore. Only start=value or initial algorithm or initial equation section can affect the initialization problem.

What you want seems to be like starting the same model with different T0 in a for loop. If this is what you want let us know and we'll give you some solutions for that.

adrpo wrote:

What you want seems to be like starting the same model with different T0 in a for loop. If this is what you want let us know and we'll give you some solutions for that.

Having an array instead would probably be the easiest way of doing that.

adrpo,

  thannnnk you,
  very well explained, I understood your answer.

  in truth, I'm trying to translate a model from Matlab to OpenModelica.

   I managed to translate all parameters, constants, equations ... etc. but my problem is that I cannot translate this instruction which is used to solve ODE.in

t_7,T_7]=ode45('Modello3',tspan,T0_7);

//

Modello3 is the function that contain ODE

.....

I know that there is DASSL solver for ode in openmodelica but I don't know how does it works

 T0_7=[16.2+273.15 16.2+273.15 16.2+273.15 16.2+273.15  16.2+273.15 16.2+273.15  32+273.15 ];

t0=0;                %Istante di tempo iniziale

tf=60;              %Istante di tempo finale

tspan=t0:1:t0+tf-1;



 for i=1:1:N_misure



[t_7,T_7]=ode45('Modello3',tspan,T0_7);

//

Modello3 is the function that contain ODE

.....



T0_7=T_7(length(T_7), : ) ;



t0=t0+length(T_7);

end