How to loop equations and expressions used by Dynare in matlab context?

Hi all,

Could anybody help me with the problem code below?

I want to loop over several equations in matlab, and the file is to be written into one equation each time.Then the file is added in another software platform (i.e., dynare) which is run in matlab. The problem is one of the equations is not straightforward but contains macro variables and loops in dynare format. So it seems such kind of equations or expressions could not be simply in the curley brace.To be concrete, I want to construct the loopover as the example shows below:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
rule ={
    'a=x;'
    'b=y;'     
    'c=rho+(
    @ # for i in number
    +eta_nu(-@{i})
    @ # endfor   
    );'
    'd=u;'  
    'e=r;'
    };
    for ii=1:size(rule,1)   
        %write equation to file
        fid=fopen('policy.mod','w');
        fprintf(fid,'%s \n',rule{ii,1});
        fclose(fid);     
    end
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%

Then the file policy.mod is added into a dynare file to run recursively. The prolem is the equation c can not be in the curley brace. Is there any other way to solve the problem? Could anybody help me ? Thank you very much!

Answer 1

[Walter Roberson]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
rule ={
    'a=x;'
    'b=y;'     
    "c=rho+(" + newline + ...
    "@ # for i in number" + newline + ...
    "+eta_nu(-@{i})" + newline + ...
    "@ # endfor   " + newline + ...
    ");"
    'd=u;'  
    'e=r;'
    };

fid=fopen('policy.mod','w');

for ii=1:size(rule,1)   
    %write equation to file
    fprintf(fid,'%s \n',rule{ii,1});
end

fclose(fid);     

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
type policy.mod

a=x; 
b=y; 
c=rho+(
@ # for i in number
+eta_nu(-@{i})
@ # endfor   
); 
d=u; 
e=r; 

If there is a particular reason why you need to fopen() inside the loop in your actual code, then you need to switch from 'w' to 'a' so that you append each time instead of overwriting each time.

[JANE TIAN]

Thank you so much for quick response, Walter Roberson.That's great help for me. Indeed I need to fopen() inside the loop, andonly one equation is used each time so that the policy.mod file here needs to be overwritten.Many many thanks once again!