Several of my functions start by allocating arrays used for intermediate 
computations in the function; these are then discarded at the end of the 
routine.  In other words, the structure of the function is like this:

    function objective1(x)
    ws1 = Array(Float64, length(x))
    ws2 = Array(Int, 2*length(x))
    # many computations involving x, ws1 and ws2
    r  # r is the return value; no need for ws1 or ws2 any more
    end

For better efficiency, I would like to rewrite this code so that these work 
arrays are allocated once and for all by main using a larger preallocated 
object called "workspace".  For example, workspace would be a large array, 
and smaller arrays would be offsets into the large array.  It could be 
organized as a Dict whose keys are the data type, like this:

    function objective1(x, workspace)
    ws1 = WorkspaceArray(Float64, length(x), workspace[Float64])  # 
allocates the space for ws1 inside an array indexed by workspace[Float64]
    ws2 = WorkspaceArray(Int, 2*length(x), workspace[Int])  
    #many computations here
    r
    end

Is there a package or language feature that already does this?  I almost 
know how to write this myself.  The part I don't get is: how can 
"workspace" detect that "objective1" has finished so that it can reset its 
internal pointers?  I know that Julia has an "atexit" function to register 
functions to be called when Julia exits.  Is there also something like an 
"atreturn" function that registers functions to be called when a function 
returns?

Thanks,
Steve Vavasis

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