FORTRAN ROUTINES FOR STORING EIRENE TRIANGULAR GRIDS IN IMAS

Content

1. Introduction
2. Files provided
3. Running a test example
4. Structure of EIRENE files
5. Presentation of EIRENE grid in GGD
6. Module  triangular_grid_modile 
7. Module  triangular_grid_ids_io 
8. Template files  save_grid.f90  and  recover_grid.f90 
9. Things to be done

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Introduction

The Fortran routines described herein are intended to become a part of interface between the code EIRENE and the IMAS data structure.  They take files containing the description of a triangular grid in native EIRENE format and store this grid in an IMAS IDS; on the other hand, they extract a stored grid description from IMAS and provide it in EIRENE format. At present, these routines have been tested only with the IDS  edge_profiles    .

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The files provided are intended to support storing triangular 2D grids in the  grid_ggd  structure. In the future (if required), they can be upgraded to support work with 3D grids consisting of a triangular 2D grid in the poloidal plane and a grid in the toroidal direction.

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Files provided

The files listed below can be found in the public directory ~g2yyakov/public/eirene/0.5.

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Running a test example

You need to have installed GSL (GGD Standard Library).

1. Open the file  gsl_config.sh  and set the value of the variable HOME to the GSL source directory location.
2. Type
   module load imasenv    
3. Create the required IMAS entry:
   imasdb eirene 
4. Type 
   . ./gsl_config.sh 
5. Now you can compile the examples. Type
   make clean 
make save 
   OR type
   ifort triangular_grid_module.f90 trangular_grid_ids_io.f90 save_grid.f90 -o save_grid.exe ${PKG_PART  }
6. Run the program:
   ./save_grid.exe 
   The program puts the grid stored in the files soledge3x.* into the IDS  edge_profiles   of the IMAS database  eirene .
7. Type
   make recover 
   OR type
   ifort triangular_grid_module.f90 trangular_grid_ids_io.f90 recover_grid.f90 -o recover_grid.exe ${PKG_PART  }
8. Run the program:
   ./recover_grid.exe 
   Compare the new files  eirene.*   with the original files  soledge3x.* .

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Structure of EIRENE files

There are three files describing the triangular grid used in EIRENE.

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Here N_i  is the index of the neighbouring triangle on side i, S_i  is the index of this side in the triangle N_i, M_i  is the ‘material property’ of the side i,   ixtri  and  iytri  are not used now (they are zeros in this example). Note that side 1 connects vertices 1 and 2; side 2, vertices 2 and 3; side 3, vertices 3 and 1. The material property (MP) is an index referring to a surface model defined in the main EIRENE file. In particular, MP is 0 for transparent (i.e., internal) grid edges. The MP of boundary edges can have different positive values. In the provides example, there are boundary edges with MP = 1, 2, 3.

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Presentation of EIRENE grid in GGD

We begin with brief overview of general principles of presentation of grids in the  grid_ggd  structure.

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At present, only items 1-4 of this lists are implemented.

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Module triangular_grid_module

The module contains a data type for storing the information about all elements of a triangular grid and a library of methods (subroutines and functions). The methods solve the following tasks:

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The module depends on the IMAS module  ids_types   (uses the constant  IDS_real  – the kind of real variables in IMAS).

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Data types provided

The following data types are provided:

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The type  edge_structure  is intended for information about an edge. The integer child array  vertex   holds indices of the edge vertices in  triangular_grid%vertex  . The leaf  material_property   holds the MP of the edge. The child array  adjacent   holds the indices of the neighbouring triangles in  triangular_grid%triangle .

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Methods provided

The module member routines are as follows:

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Read information about a triangular grid from EIRENE-format files and generate a list of grid edges (using the method  build_edges).

subroutine write_eirene_grid (grid, coord_file, triangles_file, neighbors_file, do_tests, io_unit)

Write information about a triangular grid into EIRENE-format files;

subroutine provide_grid_object_lists (grid, coordinates, edge_connect, cell_connect)

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This subroutine is no longer used in the module  triangular_grid_ids_io.f90 .

subroutine arrange_neighbors (grid)

Process a grid structure taken from IMAS, filling up the missing components of  grid%triangle  (information about neighbouring edges and triangles).

subroutine build_edges (grid)

Process a grid structure, building the missing substructure  grid % edge . The order of the edges in the substructure is as follows: side 1 of triange 1, side 2 of triange 1, side 3 of triange 1, side 1 of triangle 2 (if not accounted for earlier), side 2 of triangle 2 (if not accounted for earlier), and so on.

function give_edges_with_mat_property (grid, mat_property)

Return a list of edges with a given value of MP.

subroutine deallocate_grid (grid)

Deallocate all grid components.

For description of service routines (some of them are no longer used), see comments in the module file.

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Module  triangular_grid_ids_io

The module contains routines that support writing a grid having the  type(triangular_grid)  form to IMAS IDS and, vice versa, reading a grid from IMAS and putting it into the  type(triangular_grid)  form. It depends on the module  triangular_grid_module   and the IMAS modules  ids_schemas   and  ids_routines .

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Read data about a triangular grid from a given space of GGD grid, put it into a  type(triangular_grid)-structure and call the function  arrange_neighbors   (from  triangular_grid_module) to build the missing parts of the structure.

subroutine put_eirene_grids_to_ids (eirene_grid, coord_type, grid_ggd, nSpaces, eirene_space_index, grid_name, grid_description, eirene_space_name, eirene_space_description)

Allocate the space AOS in a given  grid_ggd   element with a given number of grid spaces, put a triangular grid given as a  type(triangular_grid)-structure into a desired element of the  space  AOS, and organize necessary grid subsets.

subroutine arrange_triangular_grid_space (space, grid, space_name, space_description)

Put a triangular grid into a given element of the  space  AOS. The grid information is taken from a  type(triangular_grid)-structure.

subroutine  arrange_standard_2d_subset(subset, space, space_index, dimensionality, subset_id)

Arrange a "standard" subset in the poloidal space – a subset of all nodes, edges, or triangular cells (depending on the dimensionality, 1, 2, or 3, respectively). The subset gets the name 'poln', where n is the dimensionality.

subroutine  arrange_mat_property_subset (subset, space, space_index, grid, mat_property, subset_id)

Arrange a subset for edges with a certain value of MP. The subset gets the name 'MPnnnn', where nnnn is the MP value.

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Template

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files  save_grid.f90

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  and  recover_grid.f90 

The program contained in the file  save_grid.f90  performs the following actions:

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• Opens the IMAS database by calling the subroutine  imas_open_env  .
• Reads the IMAS IDS  edge_profiles, using the subroutine  ids_get .
• Extracts the information about the grid from the IDS and puts it into a  type(triangular_grid)-structure, using the subroutine  get_triangular_grid_from_ids  (module  triangular_grid_ids_io).
• Writes the grid to EIRENE-format files (subroutine  write_eirene_grid, module  triangular_grid_module).
• Closes the IMAS database.

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Things to be done

• Add some simple methods for reading and writing physical data.
• Organize a 1D toroidal space and a couple of subsets in the 3D space.
• Add standard integer identifiers where appropriate.
• Try to adjust the processing of exceptions to GSL practices.
• Understand how the triangular grid can be united with the rectangular grid.

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