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Dytran™

2013

Release Guide

Worldwide Webwww.mscsoftware.com

User Documentation: Copyright 2013 MSC.Software Corporation. Printed in U.S.A. All Rights Reserved.

This document, and the software described in it, are furnished under license and may be used or copied only in accordance with the terms of such license. Any reproduction or distribution of this document, in whole or in part, without the prior written authorization of MSC.Software Corporation is strictly prohibited.

MSC.Software Corporation reserves the right to make changes in specifications and other information contained in this document without prior notice. The concepts, methods, and examples presented in this document are for illustrative and educational purposes only and are not intended to be exhaustive or to apply to any particular engineering problem or design. THIS DOCUMENT IS PROVIDED ON AN “AS-IS” BASIS AND ALL EXPRESS AND IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED, EXCEPT TO THE EXTENT THAT SUCH DISCLAIMERS ARE HELD TO BE LEGALLY INVALID.

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DT*V2013*Z*Z*Z*DC-REL.PDF

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mailto:[email protected]




http://www.mscsoftware.com

C o n t e n t sDytran Release Guide

Contents

1 Introduction

2 New Capabilities in HPC and Fluid-Structure Interaction (FSI)

1-D to 3-D Spherical-symmetric and 2-D to 3-D Axial-symmetric Mapping for Blast Loads 8

DMP Improvements for Coupling and Clumping Algorithms 15

New Interface to USA Code 18

Other Enhancements and Defect Corrections 19

List of Software Corrections in Dytran 2013 20

3 System Information

Software Installation 24

Licensing 24

Release Platforms 25

Memory Requirements 26

4 Using Dytran

Running Dytran on Linux 28

Running Dytran on Windows 29

Dytran Release Guide

4

Chapter 1: Introduction Dytran Release Guide

1 Introduction

Dytran Release Guide6

Dytran™ 2013 is the latest and most comprehensive version of Dytran released by MSC Software, bringing new simulation technology and improved performance.

Dytran 2013 is available on Linux X8664 (Red Hat 5.4, RH5.7, SUSE ES 11 SP1), Windows 32 bit and Windows 64 bit (Windows 7, Windows Server 2008, SP2). Please see System Information in chapter 3 of the Dytran 2013 Release Guide for more details.

Dytran 2013 includes major new capabilities that are primarily focused in the areas of High Performance Computing (HPC) for fluid-structure interaction (FSI) applications resulting in dramatic performance improvement for CPU intensive simulations. These are:

• 1-D to 3-D Spherical Symmetry and 2-D to 3-D Axial Symmetry Remapping for blast loads

• Enhancements to Coupling and Clumping algorithms to improve the Distributed Memory Parallel performance of FSI applications.

• New interface to USA code for Underwater Shock Explosion applications.

In addition, several critical software defects have been corrected in this release.

The Dytran 2013 DMP technology is not extended to the structural solver. The DMP capability does not require any additional licensing requirements.

The Dytran 2013 online documentation is available in PDF format on all platforms. The online documentation includes the Dytran Reference Manual, Dytran Theory Manual, Dytran User’s Guide, Dytran Example Problem Manual and Dytran Release Guide.

Dytran uses the Macrovision FLEXlm™ licensing system. If you already have a Dytran 2012 license, you will not need to obtain a new authorization code to activate Dytran 2013 on your computer. However, you will need to install the latest FLEXlm 11.9 license server.

If you need assistance while installing Dytran 2013, please call the MSC Technical Support Hotline at 1-800-732-7284, or E-mail your support questions to [email protected].

For the latest information on supported platforms for upcoming releases of MSC products, please visit the following web site: http://www.mscsoftware.com/Support/Platform-Support/Default.aspx

[email protected]

http://www.paraview.org

http://www.mscsoftware.com/Support/Platform-Support/Default.aspx

Chapter 2: New Capabilities in HPC and Fluid-structure Interaction (FSI) Dytran Release Guide

2 New Capabilities in HPC and Fluid-Structure Interaction (FSI)

1-D to 3-D Spherical-symmetric and 2-D to 3-D Axial-symmetric Mapping for Blast Loads 8

DMP Improvements for Coupling and Clumping Algorithms 15

New Interface to USA Code 18

Other Enhancements and Defect Corrections 19

List of Software Corrections in Dytran 2013 20

Dytran Release Guide1-D to 3-D Spherical-symmetric and 2-D to 3-D Axial-symmetric Mapping for Blast Loads

8

1-D to 3-D Spherical-symmetric and 2-D to 3-D Axial-symmetric Mapping for Blast LoadsTwo techniques are introduced in this release to compute the blast loads in 1-D and 2-D meshes followed by a re-map in a full 3-D mesh.

Blast wave simulations require fine mesh within and around the explosive to capture the details of the pressure wave propagation. As a result, a large three dimensional fine Eulerian mesh is often constructed that results in an increase in simulation time. During most of this time, the pressure wave is just expanding in the medium without hitting the structure. This is particularly true for far-field explosions where the distance of the detonation point with respect to the structure is rather large.

An efficient method is introduced in this release to compute the blast wave pressure by using a spherical-symmetric 1-D or axial-symmetric 2-D mesh prior to impact to the structure in a 3-D model. This requires a two step simulation process where the blast loads are written into an archive file with a 2-D or 1-D results and then read as a “remap” file in a subsequent 3-D simulation with the structure.

How It Works: 2-D to 3-D Axial-symmetry MappingTo import a 2-D-axial symmetric run into a 3-D run, the 2-D axial-symmetric element variables have to be mapped onto 3-D elements. Each element in the 2-D axial-symmetric Euler archive defines a cylinder. For each cylinder, a number of element variables like density and specific energy and velocity are specified. These cylinders are used to initialize the Euler domain in the 3-D mesh using an approach called micro zoning. A cylindrical shape in general covers only a fraction of an Euler element. To compute this fraction, the 3-D element is divided into a number of smaller elements. These smaller elements are called micro zones. Each micro zone is then examined to determine whether it is inside the cylinder. The micro zones approach will be used to do the 2-D axial symmetric to 3-D remap. The number of micro zones is by default 1000 but can be modified by using PARAM, MICRO to increase accuracy. In most simulations, using 1000 micro zones is sufficiently accurate. To activate the remapping of a 2-D axial symmetric mesh onto a 3-D, mesh the new PARAM, AXREMAP has been created.

Dytran does not have a 2-D axial symmetric solver. Therefore the 2-D axial symmetric mesh has to be a 3-D pie shape. These 3-D pies are referred to as a 2-D wedge, a 2-D mesh or simply as 2-D. These pie shaped meshes can be created by PARAM, AXIALSYM. If the angle of the pie is small, then the 3-D solvers provide good results for 2-D axial symmetric simulations. The 2-D axial symmetric simulations require a special stable timestep criterion. This criterion is activated by adding PARAM, AXIALSYM. Also, the output of Euler archives for 2-D axial symmetric simulations are output as 3-D pies.

Similar approach is followed to remap 1-D spherical elements to 3-D elements using the micro zoning methodology where the Euler archive of the 1-D spherical run defines spheres.

The 2-D mesh can be put in the 3-D mesh under an arbitrary angle. The direction of the axial axes of the 2-D mesh as viewed in the 3-D mesh is specified by the direction vector given on the PARAM, AXREMAP entry. This direction is called the 3-D axial axis. In intersecting the 2-D elements with 3-D elements, only the distance to the 3-D axial axis and the height along this axial axis is of importance. This height is called the axial height. To speed-up the computation, the 2-D axial-symmetric elements are sorted. This makes it easy to determine what 2-D elements are in the vicinity of a 3-D element.

9Chapter 2: New Capabilities in HPC and Fluid-structure Interaction (FSI)1-D to 3-D Spherical-symmetric and 2-D to 3-D Axial-symmetric Mapping for Blast Loads

The following steps are performed for remapping the blast loads in a 3-D model:

• Create a model with 2-D wedge.

• Run the model and see when the blast wave approaches the structure. Since 2-D axial-symmetric meshes do not have that many elements, Euler archives can be requested several times.

• Select a time at which the blast wave has come in the vicinity of the structure.

• Create a 3-D model and use the EULINIT option to point to the archive of the 2-D model and add PARAM,AXREMAP. Also, enter the desired cycle number.

The following example demonstrates the application of this method. For details, please refer to Chapter 3 in the Dytran Example Problem Manual.

Blast Against a Structure using 2-D Axial Symmetric to 3-D RemapFor the detailed examples, please refer to Chapter 3 in the Dytran Example Problem Manual.

The 3-D model consists of rectangular box with dimensions of 12m x 6m x 6m, with its origin at [0,0,0] and occupying the positive quadrant (Figure 2-1). A cylindrical charge is assumed to be placed with its axis coinciding with the Z-axis. The box is meshed with a uniform Cartesian mesh, 120 x 60 x 60. The symmetry walls are rigid walls by default. The positive x, y, and z directions, are defined as non-reflecting boundaries to prevent unwanted reflections.

Figure 2-1 3-D Model of Cylindrical Shape Charge Against a Structure

The axially symmetric run was calculated in the XZ-plane, for a 5m x 6m domain (see Figure 2-2). This domain was meshed by 200 x 240 elements, so that the charge radius included 14 elements. The 250kg charge is represented by an “energetic” air, to allow a single material calculation. The charge is a cylinder with L/D=2, elevated 1m above ground.


10

For Axial Symmetric Analysis, the following parameter is used:

PARAM, AXIALSYM, AXIAL, Z, ZX, 2.5

Figure 2-2 Axial Symmetric Model

Three runs were made to demonstrate the capability. For details and input models, please see these examples in Chapter 3 in the Dytran Example Problem Manual.

a. A full 3-D run with first order accuracy (HYDRO option).

b. An axially symmetric 2-D run with a fine mesh (Axial Symmetric run PARAM AXIALSYM is required).

The Archive result files from this run can be remapped in the follow-up run (c) by using PARAM, AXREMAP and FMS EULINIT entry.

c. A remap run with first order accuracy at time = 0.5 ms.

2-D Model 3-D Model for Remap


Results

(a) Normal 3-D Run (b) Axial symmetry 2-D Run (c) 3-D Remap Run

Time = 0.5 ms Time = 0.5 ms Time = 0.5 ms





12

Pressure Time History Results From Markers

How It Works: 1-D to 3-D Spherical-symmetry MappingAnother method to remap the load blasts is by using a spherical 1-D wedge model. Again, this is suitable for those applications with a spherical charge at a relatively far distance from the target.

The simulation is carried out in two stages. First, a spherical (1-D) calculation is carried out with a fine mesh to a desired time that would bring the blast wave in close proximity of the structure. Second, the spherical blast load profile is mapped into the 3-D mesh which includes the structure. The remapping of the fine mesh solution into the 3-D relatively coarse mesh is accomplished with mass, energy, and momentum conservation.

For detailed examples, please refer to Chapter 3 in the Dytran Example Problem Manual.

As an example, consider a model that consists of a cube with dimensions of 1m x 1m x 1m, with its origin at [0,0,0] and occupying the positive quadrant (Figure 2-3). A spherical charge is assumed to be placed with its center coinciding with the origin. Thus only one eighth of the charge will be included in the cube. The cube is meshed with a uniform Cartesian mesh, 80 x 80 x 80. The boundary walls are assumed rigid (by default). Some gauge points are placed to trace the blast response.

Figure 2-3 Model for Spherical Symmetry Remap

Normal 3-D Run 2-D to 3-D Remap Run


Figure 2-4a shows a full 3-D model that was run for comparative purposes with the 1-D to 3-D example. Figure 2-4b and c shows the model for the 1-D spherical wedge to compute the blast wave. Figure 2-4d shows the 3-D remap model where the results for the 1-D runs are used to map the load.

Figure 2-4 Spherical Symmetry Model

Please note that the following new parameters are used for spherical symmetry:

a. For 1-D Spherical Symmetric run PARAM, SPHERSYM is required

b. The Archive result files from this run can be remapped in the follow-up run (c) by using PARAM, SPREMAP and FMS EULINIT entry

(a) Full Run (b) Geometry Input

(d) Remap(c) Geometry Result


14

Result Comparisons

(a) Normal 3-D Run (b) Spher_sym 1-D run (c) 3-D Remap Run





15Chapter 2: New Capabilities in HPC and Fluid-structure Interaction (FSI)DMP Improvements for Coupling and Clumping Algorithms

Pressure Time History Results From Markers

DMP Improvements for Coupling and Clumping AlgorithmsAs reported in the previous release, the coupling and output generation (aka “editing” among users) calculations during a DMP FSI application has been identified as one of the major bottlenecks where it consumes a significant amount of CPU time in Dytran. This was clearly evident as the numbers of the processors were increased. The clumping is another area where significant computation is done to process the material interactions within the eulerian domain. In this release, the coupling and clumping algorithms are enhanced to reduce the bottlenecks and the overhead costs associated with communications among the cores distributed over the network.

Several benchmarks were run on a 32 cores Linux server (four sockets, each socket has 8 cores per CPU) to gauge the performance of Dytran 2013 compared to the previous release (Figure 2-5a). All seven benchmarks demonstrated that there is a good scalability and performance as the number of cores is increased. The speed-ups on 32 cores ranged from 8.43 X for Job 2 to 20.5 X for Job 3 compared to a single core run (Figure 2-5b).

Normal 3-D Run 1-D to 3-D Remap Run

Dytran Release GuideDMP Improvements for Coupling and Clumping Algorithms

16

Figure 2-5 Dytran 2013 Performance

To study the performance improvements of Dytran 2013, the benchmarks were also run with the previous release Dytran 2012 on single core (Figure 2-6a) and 32 cores (Figure 2-6b). All benchmarks showed performance improvements in Dytran 2013 ranging from 1.09X for Job 3 to 2.2X for Job 1compared to the previous release. The only poor performance on single processor was Job 6 (0.9X) that Dytran 2012 actually run a little faster. This particular model is under investigation. Job 6 performance was actually improved compared to the previous release when the number of the processors was increased to 32 cores (Figure 2-7a). The speedup factors of Dytran 2013 vs Dytran 2012 on 32 cores Linux server ranged from 1.02X for job 6 to 1.5X for Job 7 (Figure 2-7b).

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17Chapter 2: New Capabilities in HPC and Fluid-structure Interaction (FSI)DMP Improvements for Coupling and Clumping Algorithms

Figure 2-6 Dytran 2013 vs. Dytran 2012 - Single Core

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Dytran Release GuideNew Interface to USA Code

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Figure 2-7 Dytran 2013 vs. Dytran 2012 - 32 Cores

New Interface to USA CodeA new interface was created in Dytran 2013 to USA (Underwater Shock Analysis) code that is available for distribution from Livermore Software Technology Corporation (LSTC). All interested parties should contact LSTC directly for the USA license and Dytran interface to USA code.

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19Chapter 2: New Capabilities in HPC and Fluid-structure Interaction (FSI)Other Enhancements and Defect Corrections

Other Enhancements and Defect Corrections

Easy Definition of Biased Meshes A biased mesh can be defined by using BIAS entries in combination with a MESH entry. For a number of intervals, a bias can be defined. On the BIAS entry, only a growth and the number of elements could be defined for each interval. For easy definition of the bias two new options have been added to the BIAS entry. These are the start step size and end step size in an interval. For details, refer to Chapter 5 of the Dytran Reference Manual.

Force Time Histories of SubsurfacesTime histories created by using the CPLSURF + CPLSOUT entries show the forces on the coupling surfaces. Often, the force on only part of the coupling surface is also useful. To enable this, forces on subsurfaces can be requested. For this new time history output request, two new entries have been added. These are the CPLSUBS and CPLSBOUT entries. CPLSUBS requires a list of subsurfaces and CPLSBOUT requires a list of force variables. For details, refer to Chapter 4 of the Dytran Reference Manual.

Shared Memory Parallelism (SMP) for the Coupling Surface ComputationsIn almost all cases, coupling surface SMP gives good answers. But there have been some cases in which the use of coupling surface SMP did not give good answers. Therefore, coupling surface SMP has been removed. This removal does not affect Lagrangian SMP. Lagrangian SMP is fully supported, and there are no known problems with quality of results.

Flow Between Euler Domains that are Biased or Consist of Graded Meshes.With graded meshes, a fine mesh is glued into a coarse mesh. This allows for non-uniform Euler domains. In, for example, bird strike simulations, there can be flow from one Euler domain to another. In the past, the Euler domains involved had to be of uniform mesh-size. Now each of these domains can consist of a coarse mesh that has a fine mesh inserted. To use graded meshes for flow between Euler domains the SUBMESH option on the MESH entry has to be used. Also, the meshes can be biased.

Several Extensions to Flow Boundaries have been Added1. Added FLOWXSQ and FLOWXDR to allow the use of the EXFLOW user subroutines for

geometric flow boundaries. FLOWXSQ and FLOWXDR are the EXFLOW versions of FLOWSQ and FLOWDIR.

2. Added a new user subroutine EXFLOW3 that enables genuine multi-material inflow into the Euler domain. For more information, refer to Chapter 7 of the Dytran Reference Manual.

Dytran Release GuideList of Software Corrections in Dytran 2013

20

3. A symmetry option has been added to the FLOW, FLOWDIR, and FLOWSQ entries.

4. A skin friction coefficient has been added to WALLET and WALLDIR.

5. Added support of FLOWDIR and FLOWSQ for axial symmetric simulations

Enhancements of Graded MeshesGraded meshes had a major limitation. It was not allowed that the coupling surface enters the area were the coarse mesh is glued to the fine mesh. This limitation has been removed. In addition, support of graded meshes for axial symmetric simulations has been enabled.

Multiple DetonationsIn simulations with multiple detonations, the DETSPH entry of one explosive material can ignite the other explosive. In many simulations with multiple explosives, one explosive ignites the other but for some simulations this is not the case. To clarify this situation a new parameter has been added called PARAM,JWLDET with options LINK and NOLINK. With the default option LINK, the DETSPH of one explosive always applies to all other explosives. With option NOLINK, the DETSPH of one explosive cannot ignite the others.

List of Software Corrections in Dytran 2013

The following software defects are fixed in this release:

Key Title

DYT-370 Blast model euler NAN

DYT-387 Airbag problem with 512 Euler cubes takes too long

DYT-385 Viscosity (EOSPOL) no supported in conjunction with PARAM, AXIALSYM

DYT-390 DMP fails with archive error

DYT-389 Graded meshes can give error when using coupling surface

DYT-386 FSI DMP does not allow output requests for a selection of Euler elements

DYT-396 Blast model with hydrostatic flow boundaries gives DAS memory errors and coredumps

DYT-397 Geometric flow boundaries are not recognized in a run on 4 cpus

DYT-395 defective VRML viewer

DYT-402 Moving tank problem gives time step too small on 16 cpu's

DYT-399 verif/output/dmp_elements crashing on two cpus running HPMPI on lnxx8664

DYT-403 FLOWC does not support PARAM,EULERCUB

DYT-393 Airbag QA model coredumps on 32 CPUs

DYT-416 Graded mesh does not support axi-symmetry

http://jira.mscsoftware.com/browse/DYT-387














21Chapter 2: New Capabilities in HPC and Fluid-structure Interaction (FSI)List of Software Corrections in Dytran 2013

DYT-381 Euler Import of small Euler mesh into large mesh gives zero pressure outside imported mesh

DYT-415 Axi-symmetry with FLOW

DYT-414 Information of out file is not correct for FLOWDIR

DYT-292 Enhancement request for Dytran to support detonation at different times

DYT-287 Graded Mesh option produces zero mass clumps

DYT-409 Capital letter input file is error

DYT-429 Time stamp in the OUT-file gives bad information

DYT-303 FFCONTR does not allow to have an initial pressure

DYT-378 Euler Mesh Box Orientation

DYT-288 Be able to have total energy result

DYT-309 [HGW]BIAS card is not supported with Multiple coupling

DYT-410 FLOWDEF with HYDSTAT is not supported in DMP run.

DYT-404 Skin Friction for MESH Box walls

Key Title














Dytran Release GuideList of Software Corrections in Dytran 2013

22

DYT-407 Element time history output did not always work correctly for DMP

Erroneous blending for graded meshes

Summaries of holes did not take into account cubes

Allocation of array of size 0

For viscosity. the face center array was not correctly filled in case of Euler cubes

In case of markers on Euler face, marker results were not unique

Gas fractions were not communicated across cpu's

Sequential blending scheme did not work fo IG material variables

DMP blending scheme did not work for IG material variables

Special SUBSURF variables were not correctly communicated across cpu's

For MATBOX output special multi-mat variables were incorrecty retrieved

Editing comment

For glued meshes, it could happen that connections between Euler cubes were not open

Loads were incorrectly applied at segments that can potentially fail

For moving markers, data was not correctly communicated across CPUs

Small defect in transport scheme that occurs for multi-mat elements at corners and edges of cubes

The velocity gradient computation was not good at faces that connects different meshes across cpu's

Certain clump information was not deleted in time and elements were blended that should not have been blended

The center of gravities of clumps were not always correctly communicated across CPU's

Geometric properties are not in all ways correctly retrieved

The case of one coupling surface but two Euler domains was not supported yet.

Make update to cl 157148. skip communicating IDFLVL

Solve erroneous mass flow rates in boundary summaries

DYT-296 EXFLOW2/3 generates real sea waves with Dytran

DYT-428 FLOWEX is not possible for MESH entries. This has been enabled by adding the FLOWXDR and FLOWXSQ entries

DYT-430 SUBSURF time history output cannot provide forces.

DYT-433 The Undex_bubble example input deck fails in Linux machine with error as “too small timestep”

DYT-440 Enhance MESH BIAS input

Key Title






Chapter 3: System Information Dytran Release Guide

3 System Information

Software Installation 24

Licensing 24

Release Platforms 25

Memory Requirements 26

Dytran Release GuideSoftware Installation

24

Software InstallationDytran 2013 on Windows and Linux platforms can be downloaded from MSC.Software’s Solutions Download Center:

https://mscsoftware.subscribenet.com/

On the Windows platforms, Dytran 2013 can easily be installed as it uses the standard Windows Installation Wizard. On Linux platforms, the MSC.Software standard installation script can be used to install the software on your system. Dytran 2013 is the successor of Dytran 2012.

LicensingDytran uses the FLEXlm license manager as the licensing system for nodelock and network licensing.

To run Dytran, you need an authorization code from MSC.Software Corporation. If you already have a license for MSC Dytran 2012, you will not need to obtain a new license for Dytran 2013. DMP capability is part of Dytran Standard and no additional licenses are needed to run DMP capability in Dytran 2013.

However, in all cases, you do need a new installation of the license server software. Specifically, the FlexLM license server needs to be at level 10 or higher. For this purpose, an installation of FlexLM v11.9. is part of this release on all supported platforms. It is noted that Dytran 2013 is not able to check out licenses when the FlexLM server is lower than version 10.

On Windows and Linux computers, Dytran requires an Ethernet card on your computer even if your computer is not connected to a network. The FLEXlm licensing mechanism uses the Ethernet card to create the unique system identification encrypted in the license information file.

https://mscsoftware.subscribenet.com/

25Chapter 3: System InformationRelease Platforms

Release PlatformsDytran 2013 was built and tested on the following hardware with the listed software installed as given in Table 3-1.

Table 3-1 Release Platforms

Platform Operating System Compiler VersionOpenMP Support Remarks

Windows 32 Windows7 Intel Compiler Intel V 12.0* Yes Ethernet Card

Windows 64 Windows7,Windows Server 2008,SP2

Intel Compiler Intel V 12.0* Yes Ethernet Card

Linux X8664 RedHat 5.4,Redhat 5.7SUSE ES 11 SP1

Intel Compiler V 12.0 Yes Ethernet Card

*For correct operation of Intel Fortran Compiler, MS Visual Studio, NET 2010 must be installed prior to installing the Intel Compiler.

Dytran Release GuideMemory Requirements

26

Memory RequirementsIn general, the size of the memory required by Dytran depends on the size of the engineering problem you wish to solve. The default memory size is calculated by the Dytran Solver. It makes an estimate based on the number of elements, number of grid points, boundary conditions, output requests, and others. Typically, the memory does not have to be adjusted anymore starting with Dytran 2013.

You can change the preset default in the Dytran Explorer so that it fits your personal needs. In addition, you can define the minimum and maximum memory size and use the slider in the front panel to select the desired memory size. On Linux platforms, you can use the command-line option (size=small/medium/large) or you can enter the MEMORY-SIZE definition in the input file.

Dytran traces the usage of memory and prints a summary at the end of the output file of each analysis. The memory size listed in the summary is exact. It reflects the memory required for storing the model in core memory after one integration step. Additional memory required during the analysis is automatically allocated and de-allocated.

When you change the memory setting for an analysis through the Dytran Explorer, the settings are stored to be used the next time that you run the analysis. Under certain conditions, Dytran may stop and issue a message that it cannot allocate the required memory. Since the memory allocation in Dytran is dynamic, the system may require additional memory during an analysis. If the memory is available, it will be allocated and de-allocated when it is no longer needed. When your computer runs out of memory, the Dytran analysis may stop when it needs more memory to continue. You may solve this problem by closing applications on your computer that you do not need, or you can decrease the size of the core memory that Dytran allocates for the analysis if you are using substantially more than the analysis requires. You can find the information on the memory size requirements of the analysis in the memory summary at the end of the analysis. We recommend to using Dytran on a computer that has at least 4 GB of RAM.

Chapter 4: Using Dytran

Dytran Release Guide

4 Using Dytran

Running Dytran on Linux 28

Running Dytran on Windows 29

Dytran Release GuideRunning Dytran on Linux

28

Running Dytran on LinuxOn Linux platform, you would use the command line interface like:

• dytran jid=xxx (to submit a regular Dytran job)

• dytran jid=xxx bat=no (to submit Dytran in interactive mode)

• dytran jid=xxx ncpus=2 (to submit Dytran using two cores for Shared Memory Parallel)

• dytran jid=xxx exe=my_exe.exe (to submit a Dytran job with a customized executable)

To submit DMP jobs, you must specify the number of processors as well:

• dytran jid=xxx dmp=yes ncpus=2 (to submit Dytran using two cores Distributed Memory Parallel)

• dytran jid=xxx dmp=yes

• hlist=hostlist.txt bat=no (to submit Dytran in a cluster using a host list)

Note: • xxx should be replaced by the name of your input deck without the .dat extension.

• Currently, it is not possible to create customized executables for DMP.

• Hybrid SMP and DMP simulations are not possible.

29Chapter 4: Using DytranRunning Dytran on Windows

Running Dytran on WindowsOn Windows, analysis can be submitted with Dytran.Explorer, a graphical interface to control Dytran jobs and post process the results files. Double click on the Dytran icon on your desktop after the installing Dytran 2013 to start Dytran.Explorer. Alternatively, you can use the start Menu to locate Dytran.Explorer under the Programs Folder. Due to the way COM objects are used by Dytran.Explorer in newer versions of Windows, it could be necessary to run it the first time “As administrator”. Right click on the Dytran icon and select “Run as administrator”. This is needed only once, but since some pop-up windows are using specific COM objects, it may have to be repeated, when un-used windows are opened. The Dytran.Explorer provides an on line help system which includes online documentation. Basic post processing and animation tools are available by right-clicking on the results files displayed in Dytran Job window.

To submit DMP jobs, open a DOS command window and type:

{Full path to Dytran installation}\Dytran\2013\dytranexe\run_dytran.bat jid={job-name} dmp=dytran nproc={number of processors}

For instance:

1. Name input model is bunker.dat.

2. Dytran is installed at C:\MSC.Software.

3. Model needs to run on four CPUs in DMP mode.

The correct command would be:

C:\MSC.Software\Dytran\2013\dytranexe\run_dytran.bat jid=bunker dmp=dytran nproc=4

Dytran Release GuideRunning Dytran on Windows

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