1. CS 294-73 (CCN 27241) Software Engineering for Scientific Computing http://www.cs.berkeley.edu/~colella/CS294 Lecture 4: Software Engineering Practices

2. 08/25/2011CS294-73 – Lecture 6 Coding Standards When any two have gathered to work on a code, there shall be ill feelings about how the other codes things. Ignoring these issues leads to slowly building resentment -It also leads to functionally inert code changes for style reasons, that look like development in the RCS logs So, Coding Standards. -You can get mad at the standard, and want to change the standard, but it isn’t about your co-workers. Goals of a Coding Standard -Good formatting accompanies good structure (reference) -Easier to read code is often easier to understand Full Version of Coding Standard Provided from cvs repo >cvs checkout ChomboDoc/CodingStandard 2

3. 08/25/2011CS294-73 – Lecture 6 Highlights from Coding Standard Headers -// Copyright Notice (yes, writing code with us gets open-sourced) #ifndef _EBAMR_H_ #define _EBAMR_H_ #include “yourincludesGoHere.H” #include #include "NamespaceHeader.H” class BillyBob { } #include “NamespaceFooter.H” #endif 3

4. 08/25/2011CS294-73 – Lecture 6 Source files:.cpp #ifdef CH_LANG_CC /* * _______ __ * / ___/ / ___ __ _ / / ___ * / /__/ _ \/ _ \/ V \/ _ \/ _ \ * \___/_//_/\___/_/_/_/_.__/\___/ * Please refer to Copyright.txt, in Chombo's root directory. */ #endif #include "BitSet.H" #include #include "MayDay.H" #include "SPMD.H" #include ”NamespaceHeader.H" BitSet BitSetIterator::emptyBitSet = BitSet(); // class statics are at top of source file BITSETWORD BitSet::trueMasks[BITSETWORDSIZE]; int BitSet::initialize() {. #include ”NamespaceFooter.H" 4

5. 08/25/2011CS294-73 – Lecture 6 Namespace What is this namespace thing ? Chombo can be conditionally compiled to be contained in a C++ namespace. -This is put in your code by the NamespaceHeader.H and NamespaceFooter.H files. Possible Chombo namespaces -Chombo, D1, D2, D3 etc. Allows Chombo to be linked with a library where we might have a collision -For instance, Chombo and BoxLib both have a class Box Allows different dimension builds of Chombo to be linked with each other: Mixed Dim applications 5

6. 08/25/2011CS294-73 – Lecture 6 Doxygen comments Code comments should be recognizable by documentation parsers like doxygen -That is, you will document your code in doxygen format /// assignment operator. copies pointer member /** copies pointer member and integer pointer, decreases refcount of rhs member before assignment. this refcount increased my one. */ inline const RefCountedPtr & operator =(const RefCountedPtr & rhs); /// dereference access operator. use like a pointer derefence access function. inline T* operator ->(); -When the make doxygen target is executed this will generate html documentation, or LaTeX reference manual material 6

7. 08/25/2011CS294-73 – Lecture 6 Names Variable names follow the convention: -Member variables begin with an m as in m_memVar. -Argument variables begin with an a as in a_argVar. -Static variables begin with an s as in s_statVar. -Global variables begin with an g as in g_globVar. -Note, the use of global variables is heartily discouraged! Function names are likeThis() -This applies to class member functions and stand-alone functions. Function arguments are named. -For example, this is o.k.: int cramp(int base, int power);, but this is not: int cramp(int, int);. Argument names are identical in definitions and declarations. All modified arguments come before all unmodified arguments. Default values are discouraged. 7

8. 08/25/2011CS294-73 – Lecture 6 Indentation and Alignment This one we fight over, but what the hey. void AMRPoissonOp::applyOpNoBoundary(LevelData & a_lhs, const LevelData & a_phi) { CH_TIME("AMRPoissonOp::applyOpNoBoundary"); LevelData & phi = (LevelData &)a_phi; const DisjointBoxLayout& dbl = a_lhs.disjointBoxLayout(); DataIterator dit = phi.dataIterator(); phi.exchange(phi.interval(), m_exchangeCopier); for (dit.begin(); dit.ok(); ++dit) { const Box& region = dbl[dit]; FORT_OPERATORLAP(CHF_FRA(a_lhs[dit]), CHF_CONST_FRA(phi[dit]), CHF_BOX(region), CHF_CONST_REAL(m_dx), CHF_CONST_REAL(m_alpha), CHF_CONST_REAL(m_beta)); } 8