Iteration 2

• Phase: Elaboration
• Dates: Aug 30 - Sept 30, 2004

Tasks to be Completed

+ Architecture

• Finish Remaining Iteration 1 Tasks
  • Finish site-iterator classes.
  • Finish data structure to map active-site locations to their corresponding indexes into data arrays.
• Dynamic Loading Libraries, aka Plug 'n Play
  • Locate existing C++ code for dynamic libraries. Jimm knows of several open-source projects that use dynamic libs written in C++.
  • Re-use existing C++ code for dynamic libraries. This would save time, rather than having to introduce C# into the project.
  • Demonstrate dynamic libs using two Landis components (actual or test) that will read and write data to the landscape.

+ Tools

• Finish Subversion installation

+ Unified Process

• Begin writing Use Cases Have Use Cases 50% completed by end of iteration 2.

Assessment

+ Overview

Jimm completed most of the tasks outlined for iteration 2. During the iteration, the issue of binary compatibility between C++ compilers was discovered. There are several technical challenges to getting dynamic libraries made with different C++ compilers to work together. These challenges could make development by our collaborators very difficult. Jimm was able to address most of these C++ technical hurdles (although a few remain). However, these technical fixes would limit the C++ programming of module developers. We decided to spend two weeks of the next iteration exploring C# options for overcoming these limitations. Although a delay, the information gained will be valuable for future development and has the potential to speed development by streamlining how modules interact.

+ Code Demonstration

• Code was compiled and ran from a command prompt.
• Output demonstrated:
  • how a succession or disturbance component would iterate through all the active sites on the landscape, and
  • how an output component would iterate through all the sites (active and inactive) on the landscape, in order to generate an output map.
• Format of output logs is now controlled by a configuration file.

+ Iteration 2 Hits and Misses

• Miss Use Cases not 50% complete.
• Miss Did not test two components talking to the landscape.
• Miss Binary compatibility issues between differing C++ compilers not anticipated. These issues could potentially create problems for collaborating developers.
• Hit Tasks left over from Iteration 1 completed.
• Hit Subversion and two clients (Subversion interfaces) installed.
• Hit Extracted DLL code from CppUnit (an existing open-source project). Implemented simple framework and plug-in module using this DLL code.
• Big Hit Set up CppUnit, a testing framework, to perform automated testing of our code. Tests are written for each piece (unit) of our code. Not only helps determine when a unit has been completed properly, but also detects if a change "breaks" a working unit.
• Hit Developed some classes that encapsulated the dense code needed to address some of the technical issues with using C++ and DLLs. These classes would hide messy details from component developers, simplifying their jobs.

+ Iteration 2 Lessons Learned

• Uncovered the issues with DLLs (aka Plug & Play). This issue has forced us to weigh the usability (ease-of-use), future flexibility, and the schedule. The iteration assessment allowed us to narrow the decision space so we can move forward as quickly as possible.
• Iteration assessments are a valuable tool for communicating our progress, based on project team feedback.
• We can begin publishing interface specifications before the actual interface classes are finalized or even before the language is chosen (assuming that it will be in the C family of languages). This will speed collaborations with module developers.