How to set to zero all variables at each call of subroutine?

Question

Is there some simple way to initiate group of variables in Fortran subroutines? Something like DATA but working each time when subroutine is called. Or the only solution is to use x = 0.0 for all variables?

Answer 1

Yes, to set a value of a variable use an assignment (=).

You could make a derived type and a user-defined assignment to simplify the syntax.

Answer 2

I also needed to zero several variables in the beginning of a subroutine which was to be called more than once. I just copied the text used in the declaration of variables to a blank new file in the code editor and used the Find and Replace to replace all , by =0; or =0.0DE0; Here is an example:

Double precision AP(nPor), ACCor(nThr,4), ...

Replacing all (nPor), and (nThr,4), by =0.0D0;

AP=0.0D0; ACCor=0.0D0;

Then all variables were promptly set to zero. I only have not managed to use Wildcards like (*), to save the time to look at each type of arguments used in the variables though.

In case this turn around is not suitable at all, you may try to avoid the SAVE attribute in subroutines, as mentioned in Does fortran preserve the value of internal variables through function and subroutines