0003986: Serialized bigarrays do not preserve sharing

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0003986

OCaml

OCaml otherlibs

public

2006-03-09 20:18

2012-08-02 08:51

Reporter

mottl

Assigned To

Priority

normal

Severity

feature

Reproducibility

always

Status

resolved

Resolution

suspended

Platform

OS Version

Product Version

3.09.1

Target Version

Fixed in Version

Summary

0003986: Serialized bigarrays do not preserve sharing

Description

Even when marshalling functions are called with sharing of data allowed, bigarrays that share data due to "slice" and "sub" are not reconstructed in a semantically equivalent way. It's surely not that easy to efficiently implement extraction and reconstruction of the exact shared data ranges used by some bigarrays without including superfluous data. The "quick" solution of just including the whole initial data would, however, still be better than not have any sharing at all, which may lead to subtle bugs.

I have attached a file that demonstrates the problem. It prints "2 42 42 42" but should print "2 42 42 2".

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Attached Files

no_big_sharing.ml [^] (340 bytes) 2006-03-09 20:18

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Notes
(0007862) xleroy (administrator) 2012-08-02 08:51	Six years later, we still don't have any answer to this feature wish: preserving this sharing would require either major changes to the marshaller (so that custom marshallers have somehow access to the re-sharing machinery) or reimplementing Bigarrays so that proxies are represented by OCaml data structures. Plus, there would be a potential problem with a large bigarray being marshalled in full while all the user asked was to marshal a small subarray. I'm "suspending" this PR.

Issue History
Date Modified	Username	Field	Change
2006-03-09 20:18	mottl	New Issue
2006-03-09 20:18	mottl	File Added: no_big_sharing.ml
2006-03-29 16:27	doligez	Status	new => acknowledged
2012-06-21 20:16	frisch	Category	OCaml general => OCaml otherlibs
2012-07-11 16:43	doligez	Target Version	=> 4.01.0+dev
2012-07-31 13:37	doligez	Target Version	4.01.0+dev => 4.00.1+dev
2012-08-02 08:51	xleroy	Note Added: 0007862
2012-08-02 08:51	xleroy	Severity	minor => feature
2012-08-02 08:51	xleroy	Status	acknowledged => resolved
2012-08-02 08:51	xleroy	Resolution	open => suspended
2012-08-02 08:51	xleroy	Target Version	4.00.1+dev =>