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1   \appendix
2 < \chapter{\label{chapt:oopse}Object-Oriented Parallel Simulation Engine (OOPSE)}
2 > \chapter{\label{chapt:oopse}Object-Oriented Parallel Simulation Engine}
3  
4   Designing object-oriented software is hard, and designing reusable
5   object-oriented scientific software is even harder. Absence of
# Line 14 | Line 14 | documents which is crucial to the maintenance and exte
14   coordination to enforce design and programming guidelines. Moreover,
15   most MD programs also suffer from missing design and implement
16   documents which is crucial to the maintenance and extensibility.
17 + Along the way of studying structural and dynamic processes in
18 + condensed phase systems like biological membranes and nanoparticles,
19 + we developed and maintained an Object-Oriented Parallel Simulation
20 + Engine ({\sc OOPSE}). This new molecular dynamics package has some
21 + unique features
22 + \begin{enumerate}
23 +  \item {\sc OOPSE} performs Molecular Dynamics (MD) simulations on non-standard
24 + atom types (transition metals, point dipoles, sticky potentials,
25 + Gay-Berne ellipsoids, or other "lumpy"atoms with orientational
26 + degrees of freedom), as well as rigid bodies.
27 +  \item {\sc OOPSE} uses a force-based decomposition algorithm using MPI on cheap
28 + Beowulf clusters to obtain very efficient parallelism.
29 +  \item {\sc OOPSE} integrates the equations of motion using advanced methods for
30 + orientational dynamics in NVE, NVT, NPT, NPAT, and NP$\gamma$T
31 + ensembles.
32 +  \item {\sc OOPSE} can carry out simulations on metallic systems using the
33 + Embedded Atom Method (EAM) as well as the Sutton-Chen potential.
34 +  \item {\sc OOPSE} can perform simulations on Gay-Berne liquid crystals.
35 +  \item  {\sc OOPSE} can simulate systems containing the extremely efficient
36 + extended-Soft Sticky Dipole (SSD/E) model for water.
37 + \end{enumerate}
38  
39   \section{\label{appendixSection:architecture }Architecture}
40  
41 + Mainly written by \texttt{C/C++} and \texttt{Fortran90}, {\sc OOPSE}
42 + uses C++ Standard Template Library (STL) and fortran modules as the
43 + foundation. As an extensive set of the STL and Fortran90 modules,
44 + {\sc Base Classes} provide generic implementations of mathematical
45 + objects (e.g., matrices, vectors, polynomials, random number
46 + generators) and advanced data structures and algorithms(e.g., tuple,
47 + bitset, generic data, string manipulation). The molecular data
48 + structures for the representation of atoms, bonds, bends, torsions,
49 + rigid bodies and molecules \textit{etc} are contained in the {\sc
50 + Kernel} which is implemented with {\sc Base Classes} and are
51 + carefully designed to provide maximum extensibility and flexibility.
52 + The functionality required for applications is provide by the third
53 + layer which contains Input/Output, Molecular Mechanics and Structure
54 + modules. Input/Output module not only implements general methods for
55 + file handling, but also defines a generic force field interface.
56 + Another important component of Input/Output module is the meta-data
57 + file parser, which is rewritten using ANother Tool for Language
58 + Recognition(ANTLR)\cite{Parr1995, Schaps1999} syntax. The Molecular
59 + Mechanics module consists of energy minimization and a wide
60 + varieties of integration methods(see Chap.~\ref{chapt:methodology}).
61 + The structure module contains a flexible and powerful selection
62 + library which syntax is elaborated in
63 + Sec.~\ref{appendixSection:syntax}. The top layer is made of the main
64 + program of the package, \texttt{oopse} and it corresponding parallel
65 + version \texttt{oopse\_MPI}, as well as other useful utilities, such
66 + as \texttt{StatProps} (see Sec.~\ref{appendixSection:StaticProps}),
67 + \texttt{DynamicProps} (see
68 + Sec.~\ref{appendixSection:appendixSection:DynamicProps}),
69 + \texttt{Dump2XYZ} (see
70 + Sec.~\ref{appendixSection:appendixSection:Dump2XYZ}), \texttt{Hydro}
71 + (see Sec.~\ref{appendixSection:appendixSection:hydrodynamics})
72 + \textit{etc}.
73 +
74   \begin{figure}
75   \centering
76   \includegraphics[width=\linewidth]{architecture.eps}
77 < \caption[The architecture of {\sc oopse}-3.0] {The architecture of
78 < {\sc oopse}-3.0.} \label{appendixFig:architecture}
77 > \caption[The architecture of {\sc OOPSE}] {Overview of the structure
78 > of {\sc OOPSE}} \label{appendixFig:architecture}
79   \end{figure}
80  
81   \section{\label{appendixSection:desginPattern}Design Pattern}
# Line 58 | Line 112 | the modern scientific software applications, such as J
112  
113   As one of the latest advanced techniques emerged from
114   object-oriented community, design patterns were applied in some of
115 < the modern scientific software applications, such as JMol, OOPSE
116 < \cite{Meineke05} and PROTOMOL \cite{Matthey05} \textit{etc}.
115 > the modern scientific software applications, such as JMol, {\sc
116 > OOPSE}\cite{Meineke05} and PROTOMOL\cite{Matthey05} \textit{etc}.
117 > The following sections enumerates some of the patterns used in {\sc
118 > OOPSE}.
119  
120   \subsection{\label{appendixSection:singleton}Singleton}
121 < The Singleton pattern ensures that only one instance of a class is
122 < created. All objects that use an instance of that class use the same
123 < instance.
121 > The Singleton pattern not only provides a mechanism to restrict
122 > instantiation of a class to one object, but also provides a global
123 > point of access to the object. Currently implemented as a global
124 > variable, the logging utility which reports error and warning
125 > messages to the console in {\sc OOPSE} is a good candidate for
126 > applying the Singleton pattern to avoid the global namespace
127 > pollution.Although the singleton pattern can be implemented in
128 > various ways  to account for different aspects of the software
129 > designs, such as lifespan control \textit{etc}, we only use the
130 > static data approach in {\sc OOPSE}. {\tt IntegratorFactory} class
131 > is declared as
132 > \begin{lstlisting}[float,caption={[A classic Singleton design pattern implementation(I)] Declaration of {\tt IntegratorFactory} class.},label={appendixScheme:singletonDeclaration}]
133  
134 + class IntegratorFactory {
135 +  public:
136 +    static IntegratorFactory* getInstance();
137 +    protected:
138 +      IntegratorFactory();
139 +    private:
140 +      static IntegratorFactory* instance_;
141 + };
142 +
143 + \end{lstlisting}
144 + The corresponding implementation is
145 + \begin{lstlisting}[float,caption={[A classic implementation of Singleton design pattern (II)] Implementation of {\tt IntegratorFactory} class.},label={appendixScheme:singletonImplementation}]
146 +
147 + IntegratorFactory::instance_ = NULL;
148 +
149 + IntegratorFactory* getInstance() {
150 +  if (instance_ == NULL){
151 +    instance_ = new IntegratorFactory;
152 +  }
153 +  return instance_;
154 + }
155 +
156 + \end{lstlisting}
157 + Since constructor is declared as {\tt protected}, a client can not
158 + instantiate {\tt IntegratorFactory} directly. Moreover, since the
159 + member function {\tt getInstance} serves as the only entry of access
160 + to {\tt IntegratorFactory}, this approach fulfills the basic
161 + requirement, a single instance. Another consequence of this approach
162 + is the automatic destruction since static data are destroyed upon
163 + program termination.
164 +
165   \subsection{\label{appendixSection:factoryMethod}Factory Method}
70 – The Factory Method pattern is a creational pattern which deals with
71 – the problem of creating objects without specifying the exact class
72 – of object that will be created. Factory Method solves this problem
73 – by defining a separate method for creating the objects, which
74 – subclasses can then override to specify the derived type of product
75 – that will be created.
166  
167 + Categoried as a creational pattern, the Factory Method pattern deals
168 + with the problem of creating objects without specifying the exact
169 + class of object that will be created. Factory Method is typically
170 + implemented by delegating the creation operation to the subclasses.
171  
172 < \subsection{\label{appendixSection:visitorPattern}Visitor}
173 < The purpose of the Visitor Pattern is to encapsulate an operation
174 < that you want to perform on the elements of a data structure. In
175 < this way, you can change the operation being performed on a
176 < structure without the need of changing the classes of the elements
83 < that you are operating on.
172 > Registers a creator with a type identifier. Looks up the type
173 > identifier in the internal map. If it is found, it invokes the
174 > corresponding creator for the type identifier and returns its
175 > result.
176 > \begin{lstlisting}[float,caption={[The implementation of Factory pattern (I)].},label={appendixScheme:factoryDeclaration}]
177  
178 + class IntegratorFactory {
179 +  public:
180 +    typedef std::map<string, IntegratorCreator*> CreatorMapType;
181  
182 < \subsection{\label{appendixSection:templateMethod}Template Method}
182 >    bool registerIntegrator(IntegratorCreator* creator);
183  
184 +    Integrator* createIntegrator(const string& id, SimInfo* info);
185 +
186 +  private:
187 +    CreatorMapType creatorMap_;
188 + };
189 +
190 + \end{lstlisting}
191 +
192 + \begin{lstlisting}[float,caption={[The implementation of Factory pattern (II)].},label={appendixScheme:factoryDeclarationImplementation}]
193 +
194 + bool IntegratorFactory::unregisterIntegrator(const string& id) {
195 +  return creatorMap_.erase(id) == 1;
196 + }
197 +
198 + Integrator* IntegratorFactory::createIntegrator(const string& id,
199 +                                                SimInfo* info) {
200 +  CreatorMapType::iterator i = creatorMap_.find(id);
201 +  if (i != creatorMap_.end()) {
202 +    return (i->second)->create(info);
203 +  } else {
204 +    return NULL;
205 +  }
206 + }
207 +
208 + \end{lstlisting}
209 +
210 + \begin{lstlisting}[float,caption={[The implementation of Factory pattern (III)].},label={appendixScheme:integratorCreator}]
211 +
212 + class IntegratorCreator {
213 +  public:
214 +    IntegratorCreator(const string& ident) : ident_(ident) {}
215 +
216 +    const string& getIdent() const { return ident_; }
217 +
218 +    virtual Integrator* create(SimInfo* info) const = 0;
219 +
220 +  private:
221 +    string ident_;
222 + };
223 +
224 + template<class ConcreteIntegrator>
225 + class IntegratorBuilder : public IntegratorCreator {
226 +  public:
227 +    IntegratorBuilder(const string& ident) : IntegratorCreator(ident) {}
228 +    virtual  Integrator* create(SimInfo* info) const {
229 +      return new ConcreteIntegrator(info);
230 +    }
231 + };
232 + \end{lstlisting}
233 +
234 + \subsection{\label{appendixSection:visitorPattern}Visitor}
235 +
236 + The purpose of the Visitor Pattern is to encapsulate an operation
237 + that you want to perform on the elements. The operation being
238 + performed on a structure can be switched without changing the
239 + interfaces  of the elements. In other words, one can add virtual
240 + functions into a set of classes without modifying their interfaces.
241 + The UML class diagram of Visitor patten is shown in
242 + Fig.~\ref{appendixFig:visitorUML}. {\tt Dump2XYZ} program in
243 + Sec.~\ref{appendixSection:Dump2XYZ} uses Visitor pattern
244 + extensively.
245 +
246 + \begin{figure}
247 + \centering
248 + \includegraphics[width=\linewidth]{visitor.eps}
249 + \caption[The architecture of {\sc OOPSE}] {Overview of the structure
250 + of {\sc OOPSE}} \label{appendixFig:visitorUML}
251 + \end{figure}
252 +
253 + \begin{lstlisting}[float,caption={[The implementation of Visitor pattern (I)]Source code of the visitor classes.},label={appendixScheme:visitor}]
254 +
255 + class BaseVisitor{
256 +  public:
257 +    virtual void visit(Atom* atom);
258 +    virtual void visit(DirectionalAtom* datom);
259 +    virtual void visit(RigidBody* rb);
260 + };
261 +
262 + \end{lstlisting}
263 +
264 + \begin{lstlisting}[float,caption={[The implementation of Visitor pattern (II)]Source code of the element classes.},label={appendixScheme:element}]
265 +
266 + class StuntDouble {
267 +  public:
268 +    virtual void accept(BaseVisitor* v) = 0;
269 + };
270 +
271 + class Atom: public StuntDouble {
272 +  public:
273 +    virtual void accept{BaseVisitor* v*} {
274 +      v->visit(this);
275 +    }
276 + };
277 +
278 + class DirectionalAtom: public Atom {
279 +  public:
280 +    virtual void accept{BaseVisitor* v*} {
281 +      v->visit(this);
282 +    }
283 + };
284 +
285 + class RigidBody: public StuntDouble {
286 +  public:
287 +    virtual void accept{BaseVisitor* v*} {
288 +      v->visit(this);
289 +    }
290 + };
291 +
292 + \end{lstlisting}
293   \section{\label{appendixSection:concepts}Concepts}
294  
295 + \begin{figure}
296 + \centering
297 + \includegraphics[width=\linewidth]{heirarchy.eps}
298 + \caption[Class heirarchy for StuntDoubles in {\sc OOPSE}]{ The class
299 + heirarchy of StuntDoubles in {\sc OOPSE}.}
300 + \label{oopseFig:heirarchy}
301 + \end{figure}
302 +
303   OOPSE manipulates both traditional atoms as well as some objects
304   that {\it behave like atoms}.  These objects can be rigid
305   collections of atoms or atoms which have orientational degrees of
306 < freedom.  Here is a diagram of the class heirarchy:
306 > freedom.  A diagram of the class heirarchy is illustrated in
307 > Fig.~\ref{oopseFig:heirarchy}.
308  
95 – %\begin{figure}
96 – %\centering
97 – %\includegraphics[width=3in]{heirarchy.eps}
98 – %\caption[Class heirarchy for StuntDoubles in {\sc oopse}-3.0]{ \\
99 – %The class heirarchy of StuntDoubles in {\sc oopse}-3.0. The
100 – %selection syntax allows the user to select any of the objects that
101 – %are descended from a StuntDouble.} \label{oopseFig:heirarchy}
102 – %\end{figure}
309  
310   \begin{itemize}
311   \item A {\bf StuntDouble} is {\it any} object that can be manipulated by the
# Line 110 | Line 316 | Every Molecule, Atom and DirectionalAtom in {\sc oopse
316   DirectionalAtom}s which behaves as a single unit.
317   \end{itemize}
318  
319 < Every Molecule, Atom and DirectionalAtom in {\sc oopse} have their
319 > Every Molecule, Atom and DirectionalAtom in {\sc OOPSE} have their
320   own names which are specified in the {\tt .md} file. In contrast,
321   RigidBodies are denoted by their membership and index inside a
322   particular molecule: [MoleculeName]\_RB\_[index] (the contents
# Line 121 | Line 327 | expression}}
327   \section{\label{appendixSection:syntax}Syntax of the Select Command}
328  
329   The most general form of the select command is: {\tt select {\it
330 < expression}}
331 <
332 < This expression represents an arbitrary set of StuntDoubles (Atoms
333 < or RigidBodies) in {\sc oopse}. Expressions are composed of either
334 < name expressions, index expressions, predefined sets, user-defined
335 < expressions, comparison operators, within expressions, or logical
336 < combinations of the above expression types. Expressions can be
131 < combined using parentheses and the Boolean operators.
330 > expression}}. This expression represents an arbitrary set of
331 > StuntDoubles (Atoms or RigidBodies) in {\sc OOPSE}. Expressions are
332 > composed of either name expressions, index expressions, predefined
333 > sets, user-defined expressions, comparison operators, within
334 > expressions, or logical combinations of the above expression types.
335 > Expressions can be combined using parentheses and the Boolean
336 > operators.
337  
338   \subsection{\label{appendixSection:logical}Logical expressions}
339  
# Line 211 | Line 416 | expression}}
416   Users can define arbitrary terms to represent groups of
417   StuntDoubles, and then use the define terms in select commands. The
418   general form for the define command is: {\bf define {\it term
419 < expression}}
419 > expression}}. Once defined, the user can specify such terms in
420 > boolean expressions
421  
216 – Once defined, the user can specify such terms in boolean expressions
217 –
422   {\tt define SSDWATER SSD or SSD1 or SSDRF}
423  
424   {\tt select SSDWATER}
# Line 259 | Line 463 | and other atoms of type $B$, $g_{AB}(r)$.  StaticProps
463   some or all of the configurations that are contained within a dump
464   file. The most common example of a static property that can be
465   computed is the pair distribution function between atoms of type $A$
466 < and other atoms of type $B$, $g_{AB}(r)$.  StaticProps can also be
467 < used to compute the density distributions of other molecules in a
468 < reference frame {\it fixed to the body-fixed reference frame} of a
469 < selected atom or rigid body.
466 > and other atoms of type $B$, $g_{AB}(r)$.  {\tt StaticProps} can
467 > also be used to compute the density distributions of other molecules
468 > in a reference frame {\it fixed to the body-fixed reference frame}
469 > of a selected atom or rigid body.
470  
471   There are five seperate radial distribution functions availiable in
472   OOPSE. Since every radial distrbution function invlove the
# Line 318 | Line 522 | The options available for {\tt StaticProps} are as fol
522   their body-fixed frames.} \label{oopseFig:gofr}
523   \end{figure}
524  
525 + Due to the fact that the selected StuntDoubles from two selections
526 + may be overlapped, {\tt StaticProps} performs the calculation in
527 + three stages which are illustrated in
528 + Fig.~\ref{oopseFig:staticPropsProcess}.
529 +
530 + \begin{figure}
531 + \centering
532 + \includegraphics[width=\linewidth]{staticPropsProcess.eps}
533 + \caption[A representation of the three-stage correlations in
534 + \texttt{StaticProps}]{This diagram illustrates three-stage
535 + processing used by \texttt{StaticProps}. $S_1$ and $S_2$ are the
536 + numbers of selected stuntdobules from {\tt -{}-sele1} and {\tt
537 + -{}-sele2} respectively, while $C$ is the number of stuntdobules
538 + appearing at both sets. The first stage($S_1-C$ and $S_2$) and
539 + second stages ($S_1$ and $S_2-C$) are completely non-overlapping. On
540 + the contrary, the third stage($C$ and $C$) are completely
541 + overlapping} \label{oopseFig:staticPropsProcess}
542 + \end{figure}
543 +
544   The options available for {\tt StaticProps} are as follows:
545   \begin{longtable}[c]{|EFG|}
546   \caption{StaticProps Command-line Options}
# Line 379 | Line 602 | The options available for DynamicProps are as follows:
602   different vectors).  The ability to use two selection scripts to
603   select different types of atoms is already present in the code.
604  
605 + For large simulations, the trajectory files can sometimes reach
606 + sizes in excess of several gigabytes. In order to effectively
607 + analyze that amount of data. In order to prevent a situation where
608 + the program runs out of memory due to large trajectories,
609 + \texttt{dynamicProps} will estimate the size of free memory at
610 + first, and determine the number of frames in each block, which
611 + allows the operating system to load two blocks of data
612 + simultaneously without swapping. Upon reading two blocks of the
613 + trajectory, \texttt{dynamicProps} will calculate the time
614 + correlation within the first block and the cross correlations
615 + between the two blocks. This second block is then freed and then
616 + incremented and the process repeated until the end of the
617 + trajectory. Once the end is reached, the first block is freed then
618 + incremented, until all frame pairs have been correlated in time.
619 + This process is illustrated in
620 + Fig.~\ref{oopseFig:dynamicPropsProcess}.
621 +
622 + \begin{figure}
623 + \centering
624 + \includegraphics[width=\linewidth]{dynamicPropsProcess.eps}
625 + \caption[A representation of the block correlations in
626 + \texttt{dynamicProps}]{This diagram illustrates block correlations
627 + processing in \texttt{dynamicProps}. The shaded region represents
628 + the self correlation of the block, and the open blocks are read one
629 + at a time and the cross correlations between blocks are calculated.}
630 + \label{oopseFig:dynamicPropsProcess}
631 + \end{figure}
632 +
633   The options available for DynamicProps are as follows:
634   \begin{longtable}[c]{|EFG|}
635   \caption{DynamicProps Command-line Options}
# Line 405 | Line 656 | Dump2XYZ can transform an OOPSE dump file into a xyz f
656  
657   \subsection{\label{appendixSection:Dump2XYZ}Dump2XYZ}
658  
659 < Dump2XYZ can transform an OOPSE dump file into a xyz file which can
660 < be opened by other molecular dynamics viewers such as Jmol and VMD.
661 < The options available for Dump2XYZ are as follows:
659 > {\tt Dump2XYZ} can transform an OOPSE dump file into a xyz file
660 > which can be opened by other molecular dynamics viewers such as Jmol
661 > and VMD\cite{Humphrey1996}. The options available for Dump2XYZ are
662 > as follows:
663  
664  
665   \begin{longtable}[c]{|EFG|}
# Line 437 | Line 689 | converted. \\
689       & {\tt -{}-refsele} &  In order to rotate the system, {\tt -{}-originsele} and {\tt -{}-refsele} must be given to define the new coordinate set. A StuntDouble which contains a dipole (the direction of the dipole is always (0, 0, 1) in body frame) is specified by {\tt -{}-originsele}. The new x-z plane is defined by the direction of the dipole and the StuntDouble is specified by {\tt -{}-refsele}.
690   \end{longtable}
691  
692 < \subsection{\label{appendixSection:hydrodynamics}Hydrodynamics}
692 > \subsection{\label{appendixSection:hydrodynamics}Hydro}
693  
694 + {\tt Hydro} can calculate resistance and diffusion tensors at the
695 + center of resistance. Both tensors at the center of diffusion can
696 + also be reported from the program, as well as the coordinates for
697 + the beads which are used to approximate the arbitrary shapes. The
698 + options available for Hydro are as follows:
699   \begin{longtable}[c]{|EFG|}
700   \caption{Hydrodynamics Command-line Options}
701   \\ \hline
# Line 451 | Line 708 | converted. \\
708    -i & {\tt -{}-input}  &             input dump file \\
709    -o & {\tt -{}-output} &             output file prefix  (default=`hydro') \\
710    -b & {\tt -{}-beads}  &                   generate the beads only, hydrodynamics calculation will not be performed (default=off)\\
711 <     & {\tt -{}-model}  &                 hydrodynamics model (support ``AnalyticalModel'', ``RoughShell'' and ``BeadModel'') \\
711 >     & {\tt -{}-model}  &                 hydrodynamics model (supports ``AnalyticalModel'', ``RoughShell'' and ``BeadModel'') \\
712   \end{longtable}

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