RELAP5-3D in Fortran 90

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RELAP5-3D in Fortran 90

• Dr. George L Mesina

RELAP5 International Users Seminar Nov 18-20,
2008 Idaho Falls, ID
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Overview

• High-level description of conversion
• Database executable code conversion
• Effect of conversion on users and development
• Current status
• Alpha version tentative release schedule
• Summary

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F90 Project High-Level Description

• Like working on the Winchester House

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The Winchester House

• Sarah Winchester, heir to Winchester Gun Fortune,
  built the Winchester Mansion until 1922.
• Believed she couldnt die while house under
  construction.
• Builders worked 24 hours/day, every day, for 38
  years.
• Room elevations vary within a story, stairs cross
  stories or lead nowhere, doors open into walls,
  etc.
• Registered as California Historical Landmark with
  the National Park Service as "a large, odd
  dwelling with an unknown number of rooms.
• First count 140 rooms, later counts up to 160.

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Winchester House

• Floor plan developed daily as needed. No
  overarching plan.
• So convoluted, people got lost. Like a 3D maze.
• Despite construction and labyrinth, Sarah
  entertained visitors and gave tours.

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RELAP5-Winchester F90 Analogy

• RELAP5-3D had a maze-like floor plan (database)
• has a huge number of rooms (subroutines)
• with ongoing construction (by code developers)
• and visitors and tours (users, code usage)
• Riemke Repairs Davis Doors Weaver Windows
• Excavator Ed Fisher Fascia Judd Additions
  Nestle Nooks

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The Winchester Fortran 90 Analogy

• Fortran 90 Project is analogous to
• Replace ALL plumbing wiring (convert to F90)
• Without affecting the work crews (developers)
• Or impacting the owner (users)

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Fortran 90 Other Objectives

• Decomplexify the 3D labyrinth into a clear floor
  plan. Translation Make an elegantly simple
  database.
• Fix long-standing problems left by previous
  builders Translation Solve some User Trouble
  Reports.
• Dont slow down anyone elses work
  Translation Dont impact code runtime
• When done, every room left exactly as before
  Translation ALL test problems must work with no
  changes to the calculations
• Sound like a job youd want?

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Why Convert to Fortran 90?

• Numerous advantages to users
• Listed later in presentation
• Easier to read and develop
• Better for VV
• Reduced maintenance costs
• Increase code longevity

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Decomplexifying the Database

• Eliminate all equivalence statements
• These create multiple names for a
• single memory location
• Accidental data destruction
• Real equivalent-to integer created
• severe complications
• Derived type arrays organize the data w/in a group

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Decomplexifying the Database

• Example original component database
• Number of components
• Data common to all components
• Index array of component start indices
• Variable length component data stored
• contiguously OR a referral index
• Problems correct indexing, overruns
• Derived types and sub-derived types simplify data
  grouping and accessing

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Decomplexifying the Database

• Convert comdecks to modules with
• 1. Derived type and other data
• 2. Data dictionary and other
• documentation within file
• 3. Service subroutines process
• modules data
• Constructors and Destructors
• Restart Read and Write
• Some have other auxiliary routines

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Converting Source Code

• Major aspects of conversion - Declarations
• Modules replace COMDECKS for data access.
• Introduction of derived types to organize data
  into efficient and logical data groupings.
• Declarations with universal numeric types to
  reduce numeric precision problems.
• Elimination of real-to-integer equivalences.

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Converting Source Code

• Major aspects Executable Code
• Internal subroutines used to simplify code
• Restart controlled by subroutines dedicated to a
  group of data rather than entire database.
• Fortran 90 pointers introduced
• Case and multi-else if-statements introduced
• Array processing replaces loops in places
• Complete rewrites of some subroutines.

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Converting Source Code

• Fortran conversion - Statements
• Obsolescent coding eliminated or replaced.
• Machine dependent coding replaced by Fortran 90
  intrinsic functions and subroutines.
• IF-THEN and IF-THEN-ELSE constructs replace most
  GO TO statements.
• ENDDO and ENDIF replace most CONTINUE statements
• USE statements replace INCLUDE statements

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Converting Source Code

• Derived type references replace FA-
• equivalent arrays.
• Ordinal indexing replace fa-indices, simplifies
  loops.
• Fortran 90 pointers replace fa-index based
  pointers, greatly simplifies pointers.

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User Advantages

• Machine independent plot file
• Can write a plot file on a Windows or Linux
  platform with any chip
• After binary transfer, can use file to make plots
  on any other such platform
• Self-sizing memory
• No longer will your code run out of memory before
  your machine does.
• Memory is allocated according to the size
  requirements of your input

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User Advantages

• Some previously unrecognized problems corrected
• For example, time-step lower limit enforced.
• PVM multiple-RHS limit with BPLU solver fixed.
• Source Code Users
• Can now read and understand code better
• Simpler to add new data to database and program
  data services
• Simpler to add new code that uses new or old data
• Documentation easier to find and read

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User Advantages

• Longevity
• Obsolete and machine-specific coding removed
• Adjusting code to new machine chips and operating
  systems simpler in F90
• Easier to train new team members (even if they
  only know C or Java but not Fortran)
• The code will last

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Features not currently available

• RGUI RELAP5-3D Graphical User Interface
• Used to show transient calculations in 3D and
  color, to make movies of the screen display, etc.
• Conversion postponed
• The following will not be converted
• Severe Core Damage Model coding (SCDAP)
• IAEA Graphical User Interface
• Nuclear Plant Analyzer

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Status of Current Version 2.8.3

• An INL internal version created Nov 1, 2008
• Converted gt do not reference Fortran77 database.
• 81 of all 643 relap files
• 100 of 135 envrl files
• Transient semi-implicit solution fully converted
• V2.8.3 Runs all previous test cases and new ones.
• Answers same as earlier version except where
  modified for code physics developments or bug
  fixes

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Status of Current Version 2.8.3

• - INL internal version, Nov 1, 2008
• Code speed affected by remaining transfers
• Slowdown Time(v2.8.3) / Time(v2.4.1.2) 1
• tank.i 0, typp12002.i 36
• worst case pb_ss_air.i 133
• Most transfers are in syssol.F.
• Plan to eliminate all transfers and regain
  virtually all speed.

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Tentative Development/Release Schedule

• Version 2.8.3 - INL internal version, 11/08
• Transient semi-implicit solution free of FA array
• Version 2.8.4 - INL planned internal version,
  12/08
• Transient free of FA array
• Version 2.8.5 - INL planned internal version,
  1/09
• Fortran 90 conversion complete
• Version 2.9.0 tentative external release, 2/09
• ALPHA version
• Will run all previous test cases and new ones.

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Thanks to F90 Project Contributors

• Dr George Mesina PI
• Dr. Richard Riemke
• Nolan Anderson
• Hope Forsman
• Richard Moore
• Dr. Paul Murray
• Consultants Richard Wagner, Dr. Walt Weaver
• Summer students Joshua Hykes, Riley Cumberland