[Torch5-bugs] [ torch5-Bugs-1797573 ] Bug in deep copy produced by memory files

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Bugs item #1797573, was opened at 2007-09-19 01:20
Message generated for change (Settings changed) made by andresy
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Category: None
Group: None
>Status: Closed
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: thespermwhale (thespermwhale)
Assigned to: Raoul d'Andresy (andresy)
Summary: Bug in deep copy produced by memory files

Initial Comment:
Somehow the deep copy is actually only a shallow copy..
This code shows the bug:

require "torch"
require "nn"
mlp= nn.Sequential();
mlp:add(nn.Linear(5,1))
-- create a deepcopy of the mlp
file = torch.Archiver(); file:writeObject(mlp); file:seek(1)
mlp_tmp = file:readObject()
mlp_tmp:get(1).weight[1][1]=99
print(mlp_tmp:get(1).weight)
print(mlp:get(1).weight)


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Comment By: Raoul d'Andresy (andresy)
Date: 2007-10-27 00:24

Message:
Logged In: YES 
user_id=1651867
Originator: NO

this bug was actually not related to memory files, but to Archiver:
because of the tree of objects it generates internally it is non-sense to
use an Archiver in read-write mode.

all the files now can be open open in "r", "w" or "rw" mode
(read/write/read-write). by default MemoryFile opens in "rw". an Archiver
can be open only in "r" or "w" mode. asking for the file possibility is
done by methods isReadable() and isWritable().

to achieve what Jason wanted to do, one can now do:
(1) f = torch.MemoryFile() -- opened in "rw" mode by default
(2) a = torch.Archiver(f, "w") -- we want to write some stuff
(3) a:writeObject(mlp) -- we write some stuff
(4) a = torch.Archiver(f, "r") -- we want to read now!
(5) a:seek(1) -- seek at the beginning
(6) obj = a:readObject() -- we got a clone of the mlp!


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