| 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> | 
| 2 | <html> | 
| 3 | <head> | 
| 4 | <title>Selection syntax for OOPSE utility programs</title> | 
| 5 | </head> | 
| 6 | <body style="background-color: white;"> | 
| 7 | <basefont size="3"> | 
| 8 | <div align="center"> | 
| 9 | <p><font size="+2"><b>Selection syntax for OOPSE utility programs</b></font><span | 
| 10 | style="font-weight: bold;"></span><br> | 
| 11 | </p> | 
| 12 | <h2 align="left"><a name="introduction" id="introduction"> Introduction | 
| 13 | </a></h2> | 
| 14 | <p style="text-align: left;">The OOPSE utility programs compute | 
| 15 | properties from the <span | 
| 16 | style="font-family: monospace; font-weight: bold;">dump</span><span | 
| 17 | style="font-weight: bold;"> | 
| 18 | </span>files that are generated during a molecular dynamics | 
| 19 | simulation.  | 
| 20 | These programs are:<br> | 
| 21 | </p> | 
| 22 | <ul style="text-align: left;"> | 
| 23 | <li><span style="font-family: monospace; font-weight: bold;">Dump2XYZ</span><span | 
| 24 | style="font-weight: bold;"> </span>- Converts an OOPSE dump file into | 
| 25 | a file suitable | 
| 26 | for viewing in a molecular dynamics viewer like <a | 
| 27 | href="http://www.jmol.org">Jmol</a><br> | 
| 28 | </li> | 
| 29 | <li><span style="font-family: monospace; font-weight: bold;">StaticProps</span><span | 
| 30 | style="font-weight: bold;"> </span>- Computes static properties like | 
| 31 | the pair distribution function, <span style="font-style: italic;">g(r)</span>.<br> | 
| 32 | </li> | 
| 33 | <li><span style="font-family: monospace; font-weight: bold;">DynamicProps</span><span | 
| 34 | style="font-weight: bold;"> </span>- Computes time correlation | 
| 35 | functions like the | 
| 36 | velocity autocorrelation function, <span style="font-style: italic;"><<span | 
| 37 | style="font-weight: bold;">v</span>(t)<span style="font-weight: bold;">v</span>(0)></span>, | 
| 38 | or the mean square displacement <span style="font-style: italic;"><|<span | 
| 39 | style="font-weight: bold;">r</span>(t) - <span | 
| 40 | style="font-weight: bold;">r</span>(0)|<sup>2</sup>>.</span></li> | 
| 41 | </ul> | 
| 42 | <div style="text-align: left;">These programs often need to operate on | 
| 43 | a subset of the data contained within a dump file.  For example, | 
| 44 | if you want only the <span style="font-style: italic;">oxygen-oxygen</span> | 
| 45 | pair distribution from a water simulation, or if you want to make a | 
| 46 | movie including only the water molecules within a 6 angstrom radius of | 
| 47 | lipid head groups, you need a way to specify your selection to these | 
| 48 | utility programs.   OOPSE has a selection syntax which allows | 
| 49 | you to specify the selection in a compact form in order to generate | 
| 50 | only the data you want.  For example a common use of the | 
| 51 | StaticProps command would be:<br> | 
| 52 | <br> | 
| 53 | <div style="margin-left: 80px;"><span | 
| 54 | style="font-family: monospace; font-weight: bold;">StaticProps -i | 
| 55 | tp4.dump --gofr --sele1="select O*" --sele2="select O*"</span><br> | 
| 56 | </div> | 
| 57 | <br> | 
| 58 | This command computes the oxygen-oxygen pair distribution function, <span | 
| 59 | style="font-style: italic;">g<sub>OO</sub>(r)</span>, from a file | 
| 60 | named <span style="font-family: monospace;">tp4.dump</span>.  In | 
| 61 | order to understand this selection syntax and to make full use of the | 
| 62 | selection capabilities of the analysis programs, it is necessary to | 
| 63 | understand a few of the core concepts that are used to perform | 
| 64 | simulations.<br> | 
| 65 | <h2><a name="Concepts"></a>Concepts</h2> | 
| 66 | OOPSE manipulates both traditional atoms as well as some objects that <span | 
| 67 | style="font-style: italic;">behave like atoms</span>.  These | 
| 68 | objects can be rigid collections of atoms or atoms which have | 
| 69 | orientational degrees of freedom.  Here is a diagram of the class | 
| 70 | heirarchy:<br> | 
| 71 | <span style="font-style: italic;"></span></div> | 
| 72 | <p align="center"><img src="classoopse_1_1StuntDouble.png" height="136" | 
| 73 | width="292"><br> | 
| 74 | </p> | 
| 75 | <ul style="text-align: left;"> | 
| 76 | <li>A <span style="font-family: monospace; font-weight: bold;">StuntDouble</span> | 
| 77 | is <span style="font-style: italic;">any</span> object that can be | 
| 78 | manipulated by the integrators and minimizers.</li> | 
| 79 | <li>An <span style="font-family: monospace; font-weight: bold;">Atom</span> | 
| 80 | is a fundamental point-particle that can be moved around during a | 
| 81 | simulation.</li> | 
| 82 | <li>A <span style="font-family: monospace; font-weight: bold;">DirectionalAtom</span> | 
| 83 | is an atom which has <span style="font-style: italic;">orientational</span> | 
| 84 | as well as translational degrees of freedom.</li> | 
| 85 | <li>A <span style="font-family: monospace; font-weight: bold;">RigidBody</span> | 
| 86 | is a collection of <span | 
| 87 | style="font-family: monospace; font-weight: bold;">Atom</span>s or <span | 
| 88 | style="font-family: monospace; font-weight: bold;">DirectionalAtom</span>s | 
| 89 | which behaves as a <span style="font-style: italic;">single unit.</span></li> | 
| 90 | </ul> | 
| 91 | <p align="left"> Every Molecule, Atom and DirectionalAtom in OOPSE | 
| 92 | have their own names which are specified in the <span | 
| 93 | style="font-family: monospace; font-weight: bold;">.md</span> file. In | 
| 94 | contrast, RigidBodies are denoted by their membership and index inside | 
| 95 | a particular molecule: <span style="font-family: monospace;">[MoleculeName]_RB_[index]</span> | 
| 96 | (the contents inside | 
| 97 | the brackets depend on the specifics of the simulation). The names of | 
| 98 | rigid bodies are generated automatically. For | 
| 99 | example, the name of the first rigid body in a DMPC molecule is | 
| 100 | DMPC_RB_0.<br> | 
| 101 | </p> | 
| 102 | </div> | 
| 103 | <h2><a name="select"></a>Syntax of the Select Command</h2> | 
| 104 | The most general form of the select command is: <b>select <i>expression</i> | 
| 105 | </b> | 
| 106 | <p>This expression represents an arbitrary set of StuntDoubles (Atoms | 
| 107 | or | 
| 108 | RigidBodies) in OOPSE. Expressions are composed of either name | 
| 109 | expressions, index expression, predefined sets, user-defined | 
| 110 | expression, | 
| 111 | comparison operators, within expressions, or logical combinations of | 
| 112 | the above expression types. Expression can be combined using | 
| 113 | parentheses | 
| 114 | and the Boolean operators</p> | 
| 115 | <p><b><a name="logic"></a> Logical expression. </b> </p> | 
| 116 | <p>The logical operators allow complex queries to be constructed out of | 
| 117 | simpler ones using the standard boolean connectives <b>and, or, not</b>. | 
| 118 | Parentheses can be used to alter the precedence of the operators. | 
| 119 | </p> | 
| 120 | <ul> | 
| 121 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="441"> | 
| 122 | <tbody> | 
| 123 | <tr bgcolor="#ffccff"> | 
| 124 | <td width="174"> | 
| 125 | <div align="left">logical operator </div> | 
| 126 | </td> | 
| 127 | <td width="241"> | 
| 128 | <div align="left">equivalent operator</div> | 
| 129 | </td> | 
| 130 | </tr> | 
| 131 | <tr bgcolor="#ffccff"> | 
| 132 | <td> | 
| 133 | <div align="left">and</div> | 
| 134 | </td> | 
| 135 | <td> | 
| 136 | <div align="left">"&", "&&" </div> | 
| 137 | </td> | 
| 138 | </tr> | 
| 139 | <tr bgcolor="#ffccff"> | 
| 140 | <td> | 
| 141 | <div align="left">or</div> | 
| 142 | </td> | 
| 143 | <td> | 
| 144 | <div align="left">"|", "||", "," </div> | 
| 145 | </td> | 
| 146 | </tr> | 
| 147 | <tr bgcolor="#ffccff"> | 
| 148 | <td> | 
| 149 | <div align="left">not</div> | 
| 150 | </td> | 
| 151 | <td> | 
| 152 | <div align="left">"!"</div> | 
| 153 | </td> | 
| 154 | </tr> | 
| 155 | </tbody> | 
| 156 | </table> | 
| 157 | <p> </p> | 
| 158 | </ul> | 
| 159 | <p><a name="name"><b> Name expression. | 
| 160 | </b></a> </p> | 
| 161 | <ul> | 
| 162 | <table bgcolor="#ffffcc" border="1" bordercolor="#6b7683" width="886"> | 
| 163 | <tbody> | 
| 164 | <tr> | 
| 165 | <td colspan="2"> | 
| 166 | <div align="center">expression</div> | 
| 167 | </td> | 
| 168 | <td width="434"> | 
| 169 | <div align="center">description</div> | 
| 170 | </td> | 
| 171 | </tr> | 
| 172 | <tr> | 
| 173 | <td rowspan="3" width="183">expression without "." </td> | 
| 174 | <td width="247"> | 
| 175 | <div align="left">select DMPC</div> | 
| 176 | </td> | 
| 177 | <td>select all StuntDoubles belonging to all DMPC molecules </td> | 
| 178 | </tr> | 
| 179 | <tr> | 
| 180 | <td> | 
| 181 | <div align="left">select C*</div> | 
| 182 | </td> | 
| 183 | <td>select all atoms which have atom types beginning with C<br> | 
| 184 | </td> | 
| 185 | </tr> | 
| 186 | <tr> | 
| 187 | <td> | 
| 188 | <div align="left">select DMPC_RB_*</div> | 
| 189 | </td> | 
| 190 | <td>select all RigidBodies in DMPC molecules (only select | 
| 191 | rigid-bodies, but not | 
| 192 | include the atoms belong to them)</td> | 
| 193 | </tr> | 
| 194 | <tr> | 
| 195 | <td rowspan="3">expression has one "." </td> | 
| 196 | <td>select TIP3P.O_TIP3P</td> | 
| 197 | <td>select the O_TIP3P Atoms belong to TIP3P molecules </td> | 
| 198 | </tr> | 
| 199 | <tr> | 
| 200 | <td>select DMPC_RB_0.PO4</td> | 
| 201 | <td>select the PO4 Atoms belonging to first RigidBody in each | 
| 202 | DMPC molecule<br> | 
| 203 | </td> | 
| 204 | </tr> | 
| 205 | <tr> | 
| 206 | <td>select DMPC.20</td> | 
| 207 | <td>select the 20th StuntDouble in each DMPC molecule<br> | 
| 208 | </td> | 
| 209 | </tr> | 
| 210 | <tr> | 
| 211 | <td>expression has two "."</td> | 
| 212 | <td>select DMPC.DMPC_RB_?.*</td> | 
| 213 | <td>select all Atoms belonging to all rigid-bodies within all | 
| 214 | DMPC molecules</td> | 
| 215 | </tr> | 
| 216 | </tbody> | 
| 217 | </table> | 
| 218 | <p> </p> | 
| 219 | </ul> | 
| 220 | <p><a name="index" id="index"><b> Index expression </b></a></p> | 
| 221 | <ul> | 
| 222 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="894"> | 
| 223 | <tbody> | 
| 224 | <tr bgcolor="#ffffcc"> | 
| 225 | <td width="113">select 20 </td> | 
| 226 | <td width="520">select all of the StuntDoubles belonging to | 
| 227 | Molecule 20</td> | 
| 228 | </tr> | 
| 229 | <tr bgcolor="#ffffcc"> | 
| 230 | <td>select 20 to 30 </td> | 
| 231 | <td>select all of the StuntDoules belonging to molecules which | 
| 232 | have global | 
| 233 | indices between 20 (inclusive) and 30 (exclusive) </td> | 
| 234 | </tr> | 
| 235 | </tbody> | 
| 236 | </table> | 
| 237 | </ul> | 
| 238 | <p>  </p> | 
| 239 | <p><a name="predefine" id="predefine"><b> Predefined sets </b></a></p> | 
| 240 | <ul> | 
| 241 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="449"> | 
| 242 | <tbody> | 
| 243 | <tr bgcolor="#ffccff"> | 
| 244 | <td width="91"> | 
| 245 | <div align="left">keyword</div> | 
| 246 | </td> | 
| 247 | <td width="332"> | 
| 248 | <div align="left">description</div> | 
| 249 | </td> | 
| 250 | </tr> | 
| 251 | <tr bgcolor="#ffccff"> | 
| 252 | <td> | 
| 253 | <div align="left">all</div> | 
| 254 | </td> | 
| 255 | <td> | 
| 256 | <div align="left">select all StuntDoubles</div> | 
| 257 | </td> | 
| 258 | </tr> | 
| 259 | <tr bgcolor="#ffccff"> | 
| 260 | <td> | 
| 261 | <div align="left">none</div> | 
| 262 | </td> | 
| 263 | <td> | 
| 264 | <div align="left">select none of the StuntDoubles </div> | 
| 265 | </td> | 
| 266 | </tr> | 
| 267 | </tbody> | 
| 268 | </table> | 
| 269 | </ul> | 
| 270 | <p> </p> | 
| 271 | <p><a name="user" id="user"><b> User defined expressions</b></a></p> | 
| 272 | <p> Users can define arbitrary terms to represent groups of | 
| 273 | StuntDoubles, and then use the define terms in select | 
| 274 | commands. The general form for the define command is: <strong>define <em>term | 
| 275 | expression</em></strong></p> | 
| 276 | <p> Once defined, the user can specify such terms in boolean | 
| 277 | expressions </p> | 
| 278 | <ul> | 
| 279 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="659"> | 
| 280 | <tbody> | 
| 281 | <tr bgcolor="#ffffcc"> | 
| 282 | <td> | 
| 283 | <p>define SSDWATER SSD or SSD1 or SSDRF</p> | 
| 284 | <p>select SSDWATER </p> | 
| 285 | </td> | 
| 286 | </tr> | 
| 287 | </tbody> | 
| 288 | </table> | 
| 289 | </ul> | 
| 290 | <p><a name="comparison" id="comparison"> <b>Comparison expression.</b></a></p> | 
| 291 | <p>StuntDoubles can be selected by using comparision operators on | 
| 292 | their properties. The general form for the comparison command is: a | 
| 293 | property name, followed by a comparision operator and then a number.</p> | 
| 294 | <ul> | 
| 295 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="668"> | 
| 296 | <tbody> | 
| 297 | <tr bgcolor="#ffccff"> | 
| 298 | <td width="305"> | 
| 299 | <div align="left">property</div> | 
| 300 | </td> | 
| 301 | <td width="331"> | 
| 302 | <div align="left">mass, dipole, charge </div> | 
| 303 | </td> | 
| 304 | </tr> | 
| 305 | <tr bgcolor="#ffccff"> | 
| 306 | <td> | 
| 307 | <div align="left">comparision operator</div> | 
| 308 | </td> | 
| 309 | <td> | 
| 310 | <div align="left">">", "<", "=", ">=", "<=", "!=" </div> | 
| 311 | </td> | 
| 312 | </tr> | 
| 313 | </tbody> | 
| 314 | </table> | 
| 315 | </ul> | 
| 316 | <ul> | 
| 317 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="672"> | 
| 318 | <tbody> | 
| 319 | <tr bgcolor="#ffffcc"> | 
| 320 | <td width="302">select mass > 16.0 and charge < -2 </td> | 
| 321 | <td width="338">select StuntDoubles which have mass greater | 
| 322 | than | 
| 323 | 16.0 and charges less than -2 </td> | 
| 324 | </tr> | 
| 325 | </tbody> | 
| 326 | </table> | 
| 327 | </ul> | 
| 328 | <p> </p> | 
| 329 | <p><b> <a name="within"></a> Within expression.</b> | 
| 330 | </p> | 
| 331 | <p> The "within" selection allows the user to select all StuntDoubles | 
| 332 | within the specified | 
| 333 | distance (in Angstroms) from a selection, including the selected atom | 
| 334 | itself. The | 
| 335 | general form for within selection is: <b>select within(<i>distance, | 
| 336 | expression</i>) </b> | 
| 337 | </p> | 
| 338 | <ul> | 
| 339 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="681"> | 
| 340 | <tbody> | 
| 341 | <tr bgcolor="#ffffcc"> | 
| 342 | <td width="306">select within(2.5, PO4 or NC4) </td> | 
| 343 | <td width="343"> | 
| 344 | <blockquote>select all StuntDoubles which are within 2.5 | 
| 345 | angstroms of PO4 or NC4 atoms<br> | 
| 346 | </blockquote> | 
| 347 | </td> | 
| 348 | </tr> | 
| 349 | </tbody> | 
| 350 | </table> | 
| 351 | </ul> | 
| 352 | <p> | 
| 353 | </p> | 
| 354 | <h2><a name="syntax" id="syntax"> Tools which use the selection command | 
| 355 | </a></h2> | 
| 356 | <p><b><a name="within"></a> Dump2XYZ</b> | 
| 357 | </p> | 
| 358 | <p>Dump2XYZ can transform an OOPSE dump file into a xyz file which | 
| 359 | could be opened by other molecular viewers, such as Jmol and VMD. </p> | 
| 360 | <ul> | 
| 361 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="890"> | 
| 362 | <tbody> | 
| 363 | <tr bgcolor="#6699ff"> | 
| 364 | <td width="191"> | 
| 365 | <blockquote> | 
| 366 | <p>--selection</p> | 
| 367 | </blockquote> | 
| 368 | </td> | 
| 369 | <td width="667">Specifying --selection="selection command" with | 
| 370 | Dump2XYZ, user can select an arbitrary set of stuntdoubles to be | 
| 371 | converted. </td> | 
| 372 | </tr> | 
| 373 | <tr bgcolor="#ccff99"> | 
| 374 | <td> | 
| 375 | <blockquote> | 
| 376 | <p>--originsele</p> | 
| 377 | </blockquote> | 
| 378 | </td> | 
| 379 | <td rowspan="2">In order to rotate the system, --originsele and | 
| 380 | --refselec must be given to define the new coordinate set. A | 
| 381 | stuntdouble with a dipole, which direction is always (0, 0, 1) in body | 
| 382 | frame, is specified by --originsele. The new x-z plane is defined by | 
| 383 | the direction of dipole and the StuntDouble is specified by --refsele. </td> | 
| 384 | </tr> | 
| 385 | <tr bgcolor="#ccff99"> | 
| 386 | <td> | 
| 387 | <blockquote> | 
| 388 | <p>--refsele</p> | 
| 389 | </blockquote> | 
| 390 | </td> | 
| 391 | </tr> | 
| 392 | </tbody> | 
| 393 | </table> | 
| 394 | </ul> | 
| 395 | <p> | 
| 396 | </p> | 
| 397 | <p><b><a name="within"></a> StaticProps<br> | 
| 398 | </b></p> | 
| 399 | StaticProps can compute properties which are averaged over the | 
| 400 | configurations that are contained within a dump file.   The | 
| 401 | most common example of a static property that can be computed is the | 
| 402 | pair distribution function between atoms of type A and other atoms of | 
| 403 | type B, <span style="font-style: italic;">g<sub>AB</sub>(r)</span>.  | 
| 404 | StaticProps can also be used to compute the density distributions of | 
| 405 | other molecules in a reference frame <span style="font-style: italic;">fixed | 
| 406 | to the body-fixed reference frame</span> of a selected atom or rigid | 
| 407 | body.<b><br> | 
| 408 | </b> | 
| 409 | <p> </p> | 
| 410 | <p align="center"><img src="definition.jpg" height="540" width="720"></p> | 
| 411 | <p align="left">There are five seperate radial distribution functions | 
| 412 | availiable in OOPSE. Since every radial distrbution function invlove | 
| 413 | the calculation between a pair, --sele1 and --sele2 must be given. | 
| 414 | </p> | 
| 415 | <ul> | 
| 416 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="890"> | 
| 417 | <tbody> | 
| 418 | <tr bgcolor="#ccffcc"> | 
| 419 | <td width="191"> | 
| 420 | <blockquote> | 
| 421 | <p>option</p> | 
| 422 | </blockquote> | 
| 423 | </td> | 
| 424 | <td width="667"> | 
| 425 | <blockquote> | 
| 426 | <div align="center">description</div> | 
| 427 | </blockquote> | 
| 428 | </td> | 
| 429 | </tr> | 
| 430 | <tr bgcolor="#ccffcc"> | 
| 431 | <td> | 
| 432 | <blockquote> | 
| 433 | <p>--gofr</p> | 
| 434 | </blockquote> | 
| 435 | </td> | 
| 436 | <td>Computes the pair distribution function.</td> | 
| 437 | </tr> | 
| 438 | <tr bgcolor="#ccffcc"> | 
| 439 | <td> | 
| 440 | <blockquote> | 
| 441 | <p>--r_theta</p> | 
| 442 | </blockquote> | 
| 443 | </td> | 
| 444 | <td>Computes the angle-dependent pair distribution function. | 
| 445 | The | 
| 446 | angle is defined by the intermolecular vector r and z-axis of | 
| 447 | DirectionalAtom A.<br> | 
| 448 | </td> | 
| 449 | </tr> | 
| 450 | <tr bgcolor="#ccffcc"> | 
| 451 | <td> | 
| 452 | <blockquote> | 
| 453 | <p>--r_omega</p> | 
| 454 | </blockquote> | 
| 455 | </td> | 
| 456 | <td>Computes an angle-dependent pair distribution function. The | 
| 457 | angle is defined by the z-axes of the two DirectionalAtoms A and B.<br> | 
| 458 | </td> | 
| 459 | </tr> | 
| 460 | <tr bgcolor="#ccffcc"> | 
| 461 | <td> | 
| 462 | <blockquote> | 
| 463 | <p>--theta_omega</p> | 
| 464 | </blockquote> | 
| 465 | </td> | 
| 466 | <td>Calculate the pair distribution of the two angles.</td> | 
| 467 | </tr> | 
| 468 | <tr bgcolor="#ccffcc"> | 
| 469 | <td> | 
| 470 | <blockquote> | 
| 471 | <p>--gxyz</p> | 
| 472 | </blockquote> | 
| 473 | </td> | 
| 474 | <td>Calculate the density distribution of particles | 
| 475 | of type B in the body frame of particle A. Therefore, --originsele and | 
| 476 | --refsele must be given to define A's internal coordinate set. </td> | 
| 477 | </tr> | 
| 478 | </tbody> | 
| 479 | </table> | 
| 480 | </ul> | 
| 481 | <p>  </p> | 
| 482 | <p><b><a name="within"></a> DynamicProps<br> | 
| 483 | <span style="font-weight: bold;"><br> | 
| 484 | </span></b>DynamicProps computes time correlation functions from the | 
| 485 | configurations stored in a dump file.  Typical examples of time | 
| 486 | correlation functions are the mean square displacement and the velocity | 
| 487 | autocorrelation functions. <b><span style="font-weight: bold;"><br> | 
| 488 | </span> </b></p> | 
| 489 | <ul> | 
| 490 | <table bgcolor="#ffffff" border="1" cellpadding="5" width="890"> | 
| 491 | <tbody> | 
| 492 | <tr bgcolor="#ccffcc"> | 
| 493 | <td width="191"> | 
| 494 | <p align="center">option</p> | 
| 495 | </td> | 
| 496 | <td width="667"> | 
| 497 | <blockquote> | 
| 498 | <div align="center">description</div> | 
| 499 | </blockquote> | 
| 500 | </td> | 
| 501 | </tr> | 
| 502 | <tr bgcolor="#ccffcc"> | 
| 503 | <td> | 
| 504 | <p align="center">--rcorr</p> | 
| 505 | </td> | 
| 506 | <td>mean square displacement </td> | 
| 507 | </tr> | 
| 508 | <tr bgcolor="#ccffcc"> | 
| 509 | <td> | 
| 510 | <p align="center">--vcorr</p> | 
| 511 | </td> | 
| 512 | <td>velocity autocorrelation function</td> | 
| 513 | </tr> | 
| 514 | <tr bgcolor="#ccffcc"> | 
| 515 | <td> | 
| 516 | <p align="center">--dcorr</p> | 
| 517 | </td> | 
| 518 | <td>dipole correlation function </td> | 
| 519 | </tr> | 
| 520 | </tbody> | 
| 521 | </table> | 
| 522 | </ul> | 
| 523 | <p> | 
| 524 | </p> | 
| 525 | </body> | 
| 526 | </html> |