Re: [Pympi-users] Mpi and mpi.allreduce inside a function

[Pat M. <pat...@ll...>]

I tend to write things the second way

def localComputation(...):
     ...

localValue = localCompuation()
globalValue = mpi.allreduce(localValue)

I do this because it is more clear what is done
locally and simplifies the collection.

But, it is better encapsulation to do something like:

try:
   import mpi
except ImportError:
   mpi = None

...

def Compuatation(...):
    value = ...
    if mpi is not None:
         value = mpi.allreduce(value)
    return value


That way, you can call computation even if pyMPI isn't
running.

Pat

Julian wrote:
> Would it have to be something like:
>  
> GSum = mpi.allreduce(CalculateMcPrice(nSims,nSteps, Spot, Strike, Drift , vSqrdt ),mpi.SUM)
> GPrice = GSum/nSims
>  
> or simply?
>  
> Local_price = CalculateMcPrice(nSims,nSteps, Spot, Strike, Drift , vSqrdt )
> GSum = mpi.allreduce(Local_price, mpi.SUM)
> GPrice = GSum/nSims


-- 
Pat Miller | (925) 423-0309 | http://www.llnl.gov/CASC/people/pmiller

Access to power must be confined to those who are not in love with it.
  -- Plato