On Oct 24, 1:11 pm, Reckoner <[EMAIL PROTECTED]> wrote:
> I am writing an algorithm that takes objects (i.e. graphs with
> thousands of nodes) into a "hypothetical" state. I need to keep a
> history of these hypothetical objects depending on what happens to
> them later. Note that these hypothetical objects are intimately
> operated on, changed, and made otherwise significantly different from
> the objects they were copied from.
>
> I've been using deepcopy to push the objects into the hypothetical
> state where I operate on them heavily. This is pretty slow since the
> objects are very large.
>
> Is there another way to do this without resorting to deepcopy?
>
> by the way, the algorithm works fine. It's just this part of it that I
> am trying to change.
>
> Thanks in advance.
This solution takes a level of indirection.
Each graph has a stack of namespaces mapping names to nodes.
G:
{ 0: nodeA, 1: nodeB, 2: nodeC }
G-copy:
G, { 0: nodeD }
G-copy2:
G, { 1: nodeE }
G-copy-copy:
G-copy, { 3: nodeF }
If a key isn't found in the dictionary of a graph, its parent graph is
searched, and so on. Then G-copy[ 0 ] is nodeD, G-copy[ 1 ] is nodeB,
G-copy2[ 2 ] is nodeC, G-copy-copy[ 0 ] is nodeD. It might take a
significant change to your implementation, however.
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