How to free memory allocated via double[][] using dmd-2.0.12?

[Regan Heath]

Markus Dittrich wrote:
> Hi,
> 
> For a data processing application I need to read a large number
> of data sets from disk. Due to their size, they have to be read and 
> processed sequentially, i.e. in pseudocode
> 
> int main()
> {
>     while (some condition)
>     {
>          double[][] myLargeDataset = read_data();
>          process_data(myLargeDataset);
>          // free all memory here otherwise next cycle will 
>          // run out of memory
>      }
>     
>    return 0;
> }
> 
> Now, the "problem" is the fact that each single data-set saturates
> system memory and hence I need to make sure that all memory
> is freed after each process_data step is complete. Unfortunately,
> using dmd-2.012 I have not been able to achieve this. Whatever
> I do (including nothing, i.e., letting the GC do its job), the resulting 
> binary keeps accumulating memory and crashing shortly after). 
> I've tried deleting the array, setting the array lengths to 0, and manually
> forcing the GC to collect, to no avail. Hence, is there something I am 
> doing terribly wrong or is this a bug in dmd?

Did you try just setting the array reference to null.  This should make 
the contents of the array unreachable and therefore it should be 
collected when you next allocate (and run short on memory).

i.e.

int main()
{
     double[][] myLargeDataset;
     while (some condition)
     {
	 myLargeDataset = read_data();
          process_data(myLargeDataset);
          myLargeDataset = null;
      }

    return 0;
}

Regan