NAS101, Page 8 - 1 Section 8 File Management Section.

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Section 8

File Management Section

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File Management Section

PAGE

The NASTRAN Statement 4

File Management Section (FMS) 6

FMS Overview 8

DBSETs 9

Required DBSETs 11

Typical Files Generated 12

Restarts 14

Automatic Restarts (SOLs 101-200) 15

Restart Example 17

Partial Cold Start F04 File 18

Partial Cold Start F06 File 20

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File Management Section (cont.)

PAGE

Restart Example – Method 1 21

Restart Example – Method 2 23

Partial Restart F04 File 25

Partial Restart F06 File 27

Restart Example Summary 28

Manipulating The Database 29

ASSIGN and INIT Statements 31

Examples – ASSIGN and INIT 33

EXPAND Statement 36

Example – EXPAND Statement 37

Example – Assigning a FORTRAN File 39

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THE NASTRAN STATEMENT The NASTRAN statement is a member of the FMS and is

optional. It should be used to modify operational parameters (system

cells). If used, it is best to place it as the first entry in the input file.

Used only in exceptional circumstances and is not needed for most runs.

For example, to change the buffsize, add either NASTRAN BUFFSIZE=12929

or

NASTRAN SYSTEM(1)=12929

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THE NASTRAN STATEMENT (Cont.)

For example, to change the buffsize, add either

NASTRAN BUFFSIZE=12929

or

NASTRAN SYSTEM(1)=12929

See the MSC.Nastran Quick Reference Guide, Section 1, for a complete listing and description of the machine-independent system cells.

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FILE MANAGEMENT SECTION (FMS)

The FMS is optional and may not be needed for many problems.

Used to initialize or attach existing MSC.Nastran databases and FORTRAN files

The FMS commands works the same for all platforms

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FILE MANAGEMENT SECTION (FMS)

Typical applications Initializing the database (name, size, location , etc.) Splitting up a database into several smaller database sets, which allows

large problems to be solved on machines with limited disk space Expand an existing database. Restart Control.

See Section 2 of the MSC.Nastran Quick Reference Guide for detailed description of the FMS

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FMS OVERVIEW

Provides user dynamic file allocation Creation/attachment of database files Creation/attachment of FORTRAN files

Provides data manipulation Restarting Initializing and expanding the database Management of data on the database Database directory prints

Provides means of attaching external databases

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DBSETS

A DBSET is a collection of files which are used for a purpose by the program

The MSC.Nastran database consists of several DBSETs which are automatically created by the program:

MASTER - Master directory - contains the description of the database, a list of all files contained in all DBSETs used by the run, and a "table of contents" for each DBSETs.

DBALL - Permanent data is stored here by default

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DBSETS (cont.)

SCRATCH - Temporary working files for scratch data blocks - automatically deleted at the end of the run

SCR300 - Temporary working files for the modules - automatically deleted at the end of the run

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REQUIRED DBSETS

MASTER and DBALL must be retained if the database is to be used in a subsequent restart run. If no restart is planned, they may be deleted upon completion of the run.

For automatic deletion of MASTER and DBALL, use PARAM, DBALL, SCRATCH or submit with scr=yes.

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TYPICAL FILES GENERATED Files generated by submitting the input file test.dat :

test.MASTERtest.DBALLtest.f04test.f06test.log

test.pch

test.plttest.op2test.xdb

test.pch (punch file), test.plt (plot file), test.op2 (output2 file), and test.xdb (xdb file) are created by user requests.

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TYPICAL FILES GENERATED (Cont.)

If no restarts or database manipulation are planned, the user may specify that the scratch directory be used for MASTER and DBALL, files on the submittal command. They are automatically deleted upon completion of the run.

Example

nastran test scr=yes

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RESTARTS

Rigid Format Solutions (SOLs 1 thru 12) These solutions no longer support restarts.

Structured Solutions (SOLs 101,103,etc) Include automatic restart capabilities Minimal user input required for restarts Program detects what has changed in the model and process accordingly.

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AUTOMATIC RESTARTS (SOLs 101-200)

Each restart results in a new version on the the database. The previous version being used for restart is deleted at the end of the run unless the user specifies KEEP on the RESTART entry.

The entire Bulk Data is stored on the database. Only changes and additions to the Bulk Data are required in the input file for the restart. The new Bulk Data entries are merged with a copy of the Bulk Data on the database.

All solution-related Case Control commands must be in the restart file.

The program compares the Bulk Data and Case Control for the restart run with that for the previous version that is to be restarted. The program decides what needs to be calculated or recalculated for the current problem.

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AUTOMATIC RESTARTS (SOLs 101-200) (Cont.)

Only the necessary operations are performed to solve the problem.

Restarts are invoked using the RESTART statement in the FMS.

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RESTART EXAMPLE

Let’s use the stiffened plate model (workshop # 5) for a restart example

Database must be saved in the cold start run e.g. submittal command (assuming filename is soln5.dat)

• nastran soln5 scr=no

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PARTIAL COLD START F04 FILE

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PARTIAL COLD START F04 FILE (cont.)

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PARTIAL COLD START F06 FILE

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RESTART EXAMPLE—METHOD 1

DATA RECOVERY RESTART REQUEST FOR ELEMENT FORCE OUTPUT

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RESTART EXAMPLE—METHOD 1 (cont.)

Submittal Command nastran sol5a dbs=soln5

The above submittal command assumes that the cold start filename is soln5.dat and the restart filename is soln5a.dat

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RESTART EXAMPLE—METHOD 2

DATA RECOVERY RESTART REQUEST FOR ELEMENT FORCE OUTPUT

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RESTART EXAMPLE—METHOD 2 (cont.)

Submittal Command nastran sol5b

The above submittal command assumes that the cold start filename is soln5.dat and the restart filename is soln5b.dat

Note that the attachment of the database is defined inside the file soln5b.dat using the an assign statement

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PARTIAL RESTART F04 FILE

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PARTIAL RESTART F04 FILE (cont.)

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PARTIAL RESTART F06 FILE

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RESTART EXAMPLE SUMMARY

The previous restart used the same database as the cold start. Version 1 on the database was deleted because the KEEP option was not

used. If another restart is performed, it defaults to the latest version on the

database which is Version 2.

Only data recovery processing was performed for the restart run in this sample.

USE AUTOMATIC RESTARTS - IT CAN SAVE TIME AND MONEY!

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MANIPULATING THE DATABASE

All FMS defaults can be modified; however, the defaults are adequate for most analyses.

The location and maximum size of the files used for each DBsets may be specified by the user.

The database may be split across multiple physical file located on different disk packs or different machines mounted on a network.

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MANIPULATING THE DATABASE (Cont.)

Common FMS statements ASSIGN - Assigns physical file names to DBsets or FORTRAN files to be

used by other FMS statements or DMAP modules. INIT - Creates temporary or permanent DBsets EXPAND - Concatenates additonal DBsets to the existing permenant

DBsets. Used on restarts when the previous run fills the allocated DBsets DBCLEAN - Deletes previous versions from the database DBDIR - Prints the database directory

See Section 2 of the MSC.Nastran Quick Reference Guide for complete description of the FMS statements.

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ASSIGN AND INIT STATEMENTS Format (simplified)

ASSIGN dbset_member_name=physical_file_name

INIT dbset_name LOGICAL=(dbset_member_name(p),...)

where p = maximum number of blocks allocated for the member - may be specified as BLOCKS (default), megabytes (mb), megawords (mw), kilobytes (kb), or kilowords (kw) Example:

INIT DBALL, logical=(DB1(1000mb),DB2(1000mb))will create a DBALL, set, consisting of two files, each of which may grow to a maximum size of 1000 megabytes

Block size is machine specific; see The Configuration and Operations Guide for the computer you are using.

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ASSIGN AND INIT STATEMENTS (Cont.)

The maximum size of the files used in the permanent DBsets cannot be modified on a restart. Any DBset (for example, DBALL) may be expanded on a restart by adding additional files using an EXPAND entry. You should remove the ASSIGN and INIT statements for existing permanent DBSETS on the restart.

The scratch DBsets may need to be allocated for each run if the default is not adequate.

The INIT statement may be used without the ASSIGN statement to allocate a specific size to the default DBset names.

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EXAMPLES - ASSIGN AND INIT

Initializing a scratch file with a maximum size of 1000mb blocks on the SCR2 directory

ASSIGN SCR=’/scr2/test.scratch’INIT SCRATCH,LOGICAL=(SCR(1000mb)) . . .

Initializing the DBALL with 2 DBset each with a maximum size of 500mb and SCRATCH with 3 DBsets each with a maximum size of 2000mb

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EXAMPLES - ASSIGN AND INIT (Cont.)

ASSIGN DB1=’/home/mydir/sample.db1’ASSIGN DB2 =’/home/hisdir/sample.db2’ASSIGN SCR1 = ’/scr/sample.scr1’ASSIGN SCR2 =’/scr/sample.scr2’ASSIGN SCR3 =’/scr/sample.scr3’$INIT DBALL,LOGICAL=(DB1(500mb),DB2(500mb))INIT SCRATCH,LOGICAL=(SCR1(2000mb),SCR2(2000mb),

SCR3(2000mb)) . . .

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EXAMPLES - ASSIGN AND INIT (Cont.)

Note: Lowercase is shown for UNIX machines. UNIX machines are case sensitive. MSC.Nastran converts all referenced filenames to uppercase unless they are enclosed in single quotes.

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EXPAND STATEMENT

Allows the user to add a new files to an existing DBset The ASSIGN statement should be used in conjuction with the

EXPAND statement. Format:

ASSIGN dbset_member_name=phyiscal_file_name

EXPAND dbset_name LOGICAL=(dbset_member_name(p),...)

where p = number of blocks allocated for the member

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EXAMPLE - EXPAND STATEMENT

Cold start run

ASSIGN DB1= ’/home/nas101/sample.db1’ASSIGN DB2= ’/home/nas101/sample.db2’ASSIGN SCR= ’/tmp/sample.scr’$INIT DBALL,LOGICAL=(DB1(5000),DB2(5000))INIT SCRATCH,LOGICAL=(SCR(20000))$ . . .

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EXAMPLE - EXPAND STATEMENT (Cont.)

Restart run (previous run failed due to full DBALL)

RESTARTASSIGN MASTER=’sample.MASTER’ASSIGN DB3= ’/home/nas101/sample.db3’

ASSIGN SCR= ’/tmp/sample.scr’ $EXPAND DBALL,LOGICAL=(DB3(5000))INIT SCRATCH,LOGICAL=(SCR(20000))$ . . .

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EXAMPLE ASSIGNING A FORTRAN FILE

The following alter write to a formatted ASCII file the global stiffness and mass matrix for a model consisting of a single CBAR element.

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EXAMPLE ASSIGNING A FORTRAN FILE (Cont.)