ZGen

ZGen

Introduction

ZGen is a linearization system that constructs natural lnaguage sentences from bags of words, given optional input syntactic constraints. Depending on the amount of input constraints, ZGen can perform free ordering, partial tree linearization and full tree linearization.

Compiling

Prerequiest

ZGen is developed with boost and compiled by cmake, along with some C++ 0x features. To compile ZGen, the following software packages is required:

• gcc 4.5 (or above): for C++ 0x lambdas
• boost 1.55 (or above)
• cmake 2.8.10

Compiling

The compiling commands is

Run the following commands to compile on unix.

./configure
make

After successfully compiling, you will get 3 executable files under the bin folder. They are:

• ./bin/zgen-sr: The transition-based sentence linearizer.
• ./bin/zgen-bf: The best first sentence linearizer.

Usage

Input Data

ZGen accept different mount of syntactic constrains. These constraints includes the Postagging and Dependency parse structure. Constrain are input in a 4 columns data format, which means forms, postag, head, deprel. If certain lot (postag, head, deprel) is filled in the input file, it will be used to constrain the decoding process. The following example give an illustration to the barely constrainted input.

__Ms._Haag__ _ -1 _
plays _ -1 _
__Elianti__ _ -1 _
. _ -1 _

And this example is an illustration for the half postag and half dependency constrainted input.

__Ms._Haag__ _ 1 N
plays _ -1 N
__Elianti__ NP -1 _
. . 1 N

Reference Data (for training.)

If you want to train your own linearizing model with zgen, you need to prepare your reference data. The reference data should be a well-formed 4 columns dependency tree, as shown below.

_Ms._Haag__ NP 1 N
plays VBZ -1 N
__Elianti__ NP 1 N
. . 1 N

Model

Before performing sentence linearization, you need to get the corresponding model. We have provide several pretrained model on English (PennTreebank). You can download it from here.

Running ZGen

After preparing the data and model file (we suppose you put the model file in /path/to/your/model), you can run ZGen in following commands:

./bin/zgen-sr test -t none \
-t /path/to/your/model \
-i /path/to/your/input_file \
-p /path/to/your/postag_dict

The option -t is used to specify the constrain type during the decoding. If your input constrain don't contains dependency relations, please use none; If your input contains part of but not full dependency relations, you need to use partial; If your input constrains contains the full dependency relations, please use full.

The option -p is used to specify the postag dict. It's an optional resource to constrain the postag for each token, but it's highly recommanded because it will magnitudely reduce the searching space, thus speed up the decoding.

Author

• Yue Zhang (yue_z.nosp@m.hang.nosp@m.@sutd.nosp@m..edu.nosp@m..sg) developed the prototype for ZGen best-first and transition-based linearizer.
• Linfeng Song developed the joint morphlogy and generation system on ZGen:BestFrist linearizer and developed the initial version of ZGen:BestFrist linearizer.
• Yijia Liu (onepl.nosp@m.us.l.nosp@m.au@gm.nosp@m.ail..nosp@m.com) refine the transition-based linearizer and formalized the codes.
• Current maintainer for ZGen is Yijia Liu.

Licences

Please refer the LICENSES file.