| 267 | | [=#dt_sort_particles '''dt_sort_particles'''] |
| 268 | | }}} |
| 269 | | {{{#!td style="vertical-align:top" |
| 270 | | R |
| 271 | | }}} |
| 272 | | {{{#!td style="vertical-align:top" |
| 273 | | 0.0 |
| 274 | | }}} |
| 275 | | {{{#!td |
| 276 | | Temporal interval for sorting particles (in s).\\ |
| 277 | | By default, particles are sorted in memory in a way that their order follows the order in which the grid point values are stored. This may improve cache coherence in case of larger numbers of particles and grid points. However, since the sorting itself is time-consuming and since the requirement of sorting depends on the strength of mixing in the flow, performance can be improved if the sorting is applied only after certain time intervals. The proper length of this interval '''dt_sort_particles''' must be determined empirically by carrying out test runs with different intervals. Check file [../iofiles#CPU_MEASURES CPU_MEASURES] to find the value of '''dt_sort_particles''' which gives the best performance.\\\\ |
| 278 | | '''Note:''' In case of [../inipar#cloud_droplets cloud_droplets] = '' '.T.' '', any given non-zero value of '''dt_sort_particles''' will be reset to zero and a corresponding warning message will appear in the job protocol.\\\\ |
| 279 | | '''Not available from release 4.0 on.''' |
| 280 | | }}} |
| 281 | | |---------------- |
| 282 | | {{{#!td style="vertical-align:top" |
| 340 | | |---------------- |
| 341 | | {{{#!td style="vertical-align:top" |
| 342 | | [=#maximum_number_of_tailpoints '''maximum_number\\_of_tailpoints'''] |
| 343 | | }}} |
| 344 | | {{{#!td style="vertical-align:top" |
| 345 | | I |
| 346 | | }}} |
| 347 | | {{{#!td style="vertical-align:top" |
| 348 | | 100 |
| 349 | | }}} |
| 350 | | {{{#!td |
| 351 | | Maximum number of tail points that a particle tail can have. \\ |
| 352 | | '''maximum_number_of_tailpoints''' sets the number of discrete points the tail consists of. A new point is added to the particle tails after each time step. If the maximum number of tail points is reached after the corresponding number of time steps, the oldest respective tail points are deleted within the following time step. \\\\ |
| 353 | | All particle tails have the same number of points. The maximum length of these tails is determined by the value of maximum_number_of_tailpoints and by the minimum distance between each of the adjoining tail points, which can be set by [#minimum_tailpoint_distance minimum_tailpoint_distance]. Additionally, it can be determined that the temporal displacement between the current position of the particle and the oldest point of the tail may become not larger than a value to be assigned by [#maximum_tailpoint_age maximum_tailpoint_age]. |
| 354 | | }}} |
| 355 | | |---------------- |
| 356 | | {{{#!td style="vertical-align:top" |
| 357 | | [=#maximum_tailpoint_age '''maximum_tailpoint\\_age'''] |
| 358 | | }}} |
| 359 | | {{{#!td style="vertical-align:top" |
| 360 | | R |
| 361 | | }}} |
| 362 | | {{{#!td style="vertical-align:top" |
| 363 | | 100000.0 |
| 364 | | }}} |
| 365 | | {{{#!td |
| 366 | | Maximum age that the end point of a particle tail is allowed to have (in s). \\ |
| 367 | | If the temporal displacement between the oldest point of a particle tail and the current position of the particle becomes larger than the value given by '''maximum_tailpoint_age''', this oldest point (which defines the end of the tail) is removed. If this time is so small that the number of points defining the particle tail do not exceed the value given by [#maximum_number_of_tailpoints maximum_number_of_tailpoints], then the length the particle tails is a measure for the distance the particle travelled along during the time interval defined via '''maximum_tailpoint_age''', i.e. for the particle velocity. Fast particles will have long tails, slow particles shorter ones (note: this will not necessarily hold if [#minimum_tailpoint_distance minimum_tailpoint_distance] = ''0.0''). |
| 368 | | }}} |
| 369 | | |---------------- |
| 370 | | {{{#!td style="vertical-align:top" |
| 371 | | [=#minimum_tailpoint_distance '''minimum_tailpoint\\_distance'''] |
| 372 | | }}} |
| 373 | | {{{#!td style="vertical-align:top" |
| 374 | | R |
| 375 | | }}} |
| 376 | | {{{#!td style="vertical-align:top" |
| 377 | | 0.0 |
| 378 | | }}} |
| 379 | | {{{#!td |
| 380 | | Minimum distance allowed between two adjacent points of a particle tail (in m). \\ |
| 381 | | In case of '''minimum_tailpoint_distance''' > ''0.0'' the particle tail is extended by a new point only if the distance between its current position and the most recent tail point exceed the distance given via '''minimum_tailpoint_distance'''.\\ |
| 382 | | If the length of the particle tails shall be proportional to the respective particle velocity, the parameter [#maximum_tailpoint_age maximum_tailpoint_age] must also be set appropriately.\\\\ |
| 383 | | '''Note:''' A suitable choice of minimum_tailpoint_distance > 0.0 is recommended, because then the tail coordinates of slowly moving particles require less memory and can also be drawn faster. The upper limit of minimum_tailpoint_distance should be chosen in a way that the visualized particle tails still appear as smooth lines. Example: with a model domain of 1000 m and a monitor resolution of 1280 * 1024 pixels it should be sufficient to set '''minimum_tailpoint_distance''' = ''5.0 (m).'' |
| 384 | | }}} |
| 654 | | [=#skip_particles_for_tail '''skip_particles_\\for_tail'''] |
| 655 | | }}} |
| 656 | | {{{#!td style="vertical-align:top" |
| 657 | | I |
| 658 | | }}} |
| 659 | | {{{#!td style="vertical-align:top" |
| 660 | | 100 |
| 661 | | }}} |
| 662 | | {{{#!td |
| 663 | | Limit the number of particle tails.\\ |
| 664 | | If particle tails are switched on (see [#use_particle_tails use_particle_tails]), every particle is given a tail by default. '''skip_particles_for_tail''' can be used to give only every n'th particle a tail.\\\\ |
| 665 | | '''Example:''' '''skip_particles_for_tail''' = ''10'' means that only every 10th particle will be given a tail. |
| 666 | | }}} |
| 667 | | |---------------- |
| 668 | | {{{#!td style="vertical-align:top" |
