Here are the steps to run terrier TF-IDF retrieval:
Setup:
1- Download terrier from "http://terrier.org/download/". When running the TF-IDF for task 1, we used version 5.2.
2- Download the processed files that will be used for indexing from ARQMath google drive, in the "xmls.zip" file.
3- Extract to the zip file and update the collection.spec accordingly. Please note that each line in the collection.spec is referring to one file extracted from xmls.zip.
4- Modify the terrier.properties file, located in etc directory, with the one on ARQMath's google drive. Here are important parts to modify:
	- collection.spec: this is the file path to collection.spec file.
	- trec.topics: file path to qrel_main.xml. This file contains the questions from Task 1.
5- Update the terrier.properties in the "etc" directory with the one updated in step 4.
Indexing:
1- Go to the terrier directory.
2- run the following command to do the indexing: (Please visit terrier website for more information, "http://terrier.org/docs/v5.1/quickstart_experiments.html")
	bin/terrier batchindexing
Note: The index files will be in directory "var/index".

Retrieval:
1- Download the qrel_main.xml file and locate it in the share directory in terrier.
1- Go to terrier directory.
2- Run the following command,
	bin/terrier batchretrieve -t share/qrel_main.xml
Note: qrel_main.xml should be the complete file path to qrel file. 

The retrieval results will be available in the var/results directory.