Re: Defining block size during runtime

From: sainath l (ls.sainath_at_gmail_dot_com)
Date: Thu Jul 23 2009 - 16:23:52 PDT

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    Hello ,
    
    Thanks again Gary.
    
    
    Cheers,
    sainath
    
    
    
    
    
    On Thu, Jul 23, 2009 at 6:19 AM, Gary Funck <gary_at_intrepid_dot_com> wrote:
    
    > On 07/23/09 02:00:02, sainath l wrote:
    > >    I am very much interested in knowing any workaround, if possible, for
    > >    dynamically allocating an array with variable block size at runtime.
    > >
    > >    Lets say I want to know if it is possible to create the following
    > array
    > >    dynamically where N and M are some variables. If yes then how can we
    > do
    > >    it.
    > >
    > >    shared [M] int A[N][M];
    >
    > Sainath,
    > I'm not sure if this is what you're asking about, but attached is
    > a program that uses a "trick" to ensure that each row of the array
    > has affinity to a single thread, in a thread-cyclic fashion.
    >
    > The trick is that by placing the row vector 'y' inside of
    > struct, we ensure that y is allocated contiguously on a
    > given thread.  And for each a[i+1] (based upon UPC's
    > indexing rules) we know that it will be allocated on
    > the next thread (in cyclic order) after thread 'i'.
    >
    > $ upc alloc_row_struct.upc -o alloc_row_struct
    > $ alloc_row_struct -n 4 4 5
    > threadof a[0].y[0] = 0
    > threadof a[0].y[1] = 0
    > threadof a[0].y[2] = 0
    > threadof a[0].y[3] = 0
    > threadof a[0].y[4] = 0
    > threadof a[1].y[0] = 1
    > threadof a[1].y[1] = 1
    > threadof a[1].y[2] = 1
    > threadof a[1].y[3] = 1
    > threadof a[1].y[4] = 1
    > threadof a[2].y[0] = 2
    > threadof a[2].y[1] = 2
    > threadof a[2].y[2] = 2
    > threadof a[2].y[3] = 2
    > threadof a[2].y[4] = 2
    > threadof a[3].y[0] = 3
    > threadof a[3].y[1] = 3
    > threadof a[3].y[2] = 3
    > threadof a[3].y[3] = 3
    > threadof a[3].y[4] = 3
    >
    > Above '-n 4' indicates that the program will run on 4 threads.
    > That number was chosen to agree with the value of N (also 4)
    > given above, but in fact could be any number.
    >
    > Whether this is the best method, or even a recommended practice,
    > for accomplishing your objective, I'm not sure.  Perhaps others
    > on the list can offer some comment or suggest alternative
    > methods?
    >
    > - Gary
    >
    

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