Clean up the function calls to domain_decomposition from main

[mortele]

These long function calls to domain_decomposition(...) with many lines of arguments doubled by the if test clause for the molecules being present is getting cumbersome. Look into rewriting this in a more sane way, so we can add conditional arrays to the decomposition without having to add 2ⁿ if test clauses, each with it's own 10+ lines of arguments. See discussion from #72.

[xinmeng2020]

@mortele Referring your example code #72, put the args in a tuple looks nice. I just add that we need a * operator to unpack the tuple:

args = tuple(args[:10 + int(charges_flag) + int(mass_flag)])
dd = domain_decomposition(
    *args,  ##args  
    ...
)   

## testing
def f (a, b, c):
    return a*b*c

x = tuple([3, 5 ])
print(   f(*x, 10 )  ) ## 150

[mortele]

Ah, yes, thanks. Editing the example in #72.

[xinmeng2020]

I tried to define two args arg_in and arg_recv; but I think using arg_recv in my try here is a silly mistake.. As when the tuple is generated the values are used, not the variables, thus I still have to make the args_recv explicit.

• Although it is possible to transform the explicit list as a string, and execute it using e.g. exec function in python, which will still keep the _argrecv = dd as single line. I not sure whether that will be too strange (see the code in the next reply).

    !!!!!!!!!!!!!!!!!!!!!!!!!! NOT CORRECT, can ignore !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    Affiliated_DD_Args_in_Len = 9 ## can also use the append without defining the length ?
    args_in = [None for _ in range(Affiliated_DD_Args_Len)]
    args_in[:7] = [
         velocities,
         indices,
         bond_forces,
         angle_forces,
         field_forces,
         names, 
         types
    ]
    if charges_flag: ## add charge related 
        args_in[7] = charges 
        args_in[8] = field_q_forces  

    ## args_recv for the (..) = dd
    args_recv = args_in.copy()
    args_recv.insert(0, positions)
    if molecules_flag:
        args_recv.append(bonds)
        args_recv.append(molecules)
    ## convert to tuple
    args_in = tuple(args_in)
    args_recv= tuple(args_recv)

    ############### DD 
    if config.domain_decomposition:
        dd = domain_decomposition(
            positions,
            pm,
            *args_in,
            molecules=molecules if molecules_flag else None,
            bonds=bonds if molecules_flag else None,
            verbose=args.verbose,
            comm=comm,
        )
        args_recv = dd  #<------------ WRONG 

[xinmeng2020]

Hi @mortele, this is a rewriting of the call about the domain_decomposition() function.

• this introduces two variables: args_in (tuple of variables) and args_recv (list of strings);
• the tricks is to convert the variables inside args_recv to a string and execute the string as code;
• the benefit is that we can handle all the flag conditions once for all;
• special care needed about the exec function in python, for safety and speed;
• I tested in a short DPPC run. No error while running

    args_in = [
         velocities,
         indices,
         bond_forces,
         angle_forces,
         field_forces,
         names, 
         types
    ]
    args_recv = [
         'positions',
         'velocities',
         'indices',
         'bond_forces',
         'angle_forces',
         'field_forces',
         'names', 
         'types'
    ]

    if charges_flag: ## add charge related 
        args_in.append(charges) 
        args_in.append(field_q_forces)
        args_recv.append('charges')
        args_recv.append('field_q_forces')

    if molecules_flag:
        args_recv.append('bonds')
        args_recv.append('molecules')

    ## convert to tuple
    args_in = tuple(args_in)

    ## cmd string to excecut the (...) = dd 
    _str_receive_dd =  ','.join(args_recv)
    _cmd_receive_dd = f"({_str_receive_dd }) = dd"

    ############### DD 
    if config.domain_decomposition:
        dd = domain_decomposition(
            positions,
            pm,
            *args_in,
            molecules=molecules if molecules_flag else None,
            bonds=bonds if molecules_flag else None,
            verbose=args.verbose,
            comm=comm,
        )
        exec(_cmd_receive_dd ) 

[mortele]

Nice work! We should meet on Monday to discuss!

[xinmeng2020]

Nice work! We should meet on Monday to discuss!

👌😄 see you on Monday~