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What's New?

CGNS Documentation

11 January 2011
  • Caught up with postings of telecon minutes. Added CGNS Tutorial slides from Orlando Jan 2010. Added 2008-2009 CGNSTalk archives.
26 May 2009
  • In the Applications Software section of the CGNS Overview and Entry-Level Document, changed the contact person for notification about new CGNS applications.
  • In the SIDS document, deleted the contact info for questions about the SIDS, since it was no longer valid, and is now covered by the CGNStalk mailing list.
22 May 2009
  • Posted draft minutes from the May 20 CGNS Steering Committee telecon. (HTML, PDF).
21 May 2009
  • In the Accessing a Node description in the "Navigating a CGNS File" section of the Mid-Level Library document, corrected an error in the syntax for the cg_gopath_f Fortran routine. The last two arguments were reversed. Thanks to Richard McDonald at the USGS for the correction.
20 May 2009
  • In the Steering Committee Charter, deleted the list of current member organizations in the Organization/Bylaws section. This is now available at the CGNS web site.
12 May 2009
  • In the Zone Information description in the "Structural Nodes" section of the Mid-Level Library document, added a sentence emphasizing that zones must be named alphanumerically to ensure proper retrieval.
6 Apr 2009
  • Posted draft minutes from the Apr 1 CGNS Steering Committee telecon. (HTML, PDF).
14 Jan 2009
9 Jan 2009
  • Posted draft minutes from the Jan 7 CGNS Steering Committee meeting. (HTML, PDF).
19 Nov 2008
  • Posted draft minutes from the Nov 5 CGNS Steering Committee telecon. (HTML, PDF).
9 Oct 2008
  • Added AIAA Paper 2008-0479, titled "Benchmarking the CGNS I/O Performance," by Thomas Hauser, presented at the 46th AIAA Aerospace Sciences Meeting and Exhibit. [HTML, PDF (318K, 8 pages)]
23 Sep 2008
  • Posted draft minutes from the Sep 10 CGNS Steering Committee telecon. (HTML, PDF).
11 Sep 2008
  • In the Mid-Level Library manual, added a note to the descriptions of the routines for grid coordinates, element connectivity, and flow solution, saying that partial reads and writes will not work correctly in CGNS 2.5 when HDF5 is being used as the underlying database manager.
17 July 2008
  • Modified each page to use server-side includes for adding the footer.
11 July 2008
  • Posted draft minutes from the July 2 CGNS Steering Committee telecon. (HTML, PDF).
27 May 2008
  • Posted draft minutes from the May 7 CGNS Steering Committee telecon. (HTML, PDF).
14 May 2008
  • Made a minor change in the Getting Started section of the User's Guide to CGNS, involving the use of PointList or PointRange with GridLocation set to FaceCenter.
12 Mar 2008
7 Mar 2008
8 Feb 2008
  • Added HTML versions of all the PDF attachments to meeting and telecon minutes.
29 Jan 2008
23 Jan 2008
18 Jan 2008
  • Posted draft minutes from the Jan 6 CGNS Steering Committee meeting. (HTML, PDF).
5 Dec 2007
  • Added an "external link" symbol (external link symbol) to all links to non-NASA sites, per NASA policy.
29 Nov 2007
  • Posted draft minutes from the Nov 28 CGNS Steering Committee telecon. (HTML, PDF).
7 Nov 2007
  • Modified the description of the TurbulenceModel_t structure to add references to the specific models that correspond to the TurbulenceModelType names, and to add a recommendation for handling subsequent changes to the models.
  • In the User's Guide to CGNS, added a note that it was originally published as NASA/TM-2001-211236, October 2001.
9 Oct 2007
  • Modified the list of current member organizations in the CGNS Steering Committee Charter to reflect the name change of Thaerocomp Technical Corporation to TTC Technologies.
19 Sep 2007
  • Posted minutes from the Sept 12 CGNS Steering Committee telecon. (HTML, PDF).
14 Sep 2007
11 July 2007
5 July 2007
  • In the SIDS document, rearranged discussion of the AIAA Recommended Practice version of the SIDS, noting that it's out of date, and removed links to it on the CGNS documentation home page.
19 June 2007
  • Posted minutes from the May 22 CGNS Steering Committee telecon. (HTML, PDF).
26 Mar 2007
  • Posted minutes from the Mar 21 CGNS Steering Committee telecon. (HTML, PDF).
30 Jan 2007
  • Corrected a minor error in Mid-Level Library document, changing the error status names ALL_OK, ERROR, NODE_NOT_FOUND, and INCORRECT_PATH to CG_OK, CG_ERROR, CG_NODE_NOT_FOUND, and CG_INCORRECT_PATH, respectively.
17 Jan 2007
  • Corrected an error in SIDS document, in the description of the unstructured grid element numbering conventions for pyramid elements. For the PYRA_14 element, node 14 should be at the center of the quadrilateral face, not the center of the element.
  • Several modifications to the Mid-Level Library manual, for consistency with the current CGNS Version 2.5 beta.
    • New functions to check file validity and configure some internal CGNS library options.
    • Additional functions providing alternate ways to access a node.
    • Changes in the use of functions for partial writes of coordinate, element, and solution data. The result is now always the union of the existing and new data. As part of this, the functions cg_section_read_ext and cg_elements_read_ext are no longer needed and have been removed, and new functions cg_ElementPartialSize and cg_elements_partial_read have been added.
  • Corrected typo in the data type of the argument data in the Mid-Level Library function cg_free.
30 Nov 2006
  • Corrected error in the table at the top of the Export Utilities section. cgns_to_tecplot converts from CGNS to Tecplot, not the other way round.
16 Oct 2006
  • Corrected an error in the Mid-Level Library manual, in the argument list for cg_conn_write_short. Even though the specific cell connectivity data aren't needed, the name of the donor zone is still required. Thanks to Thorsten Schwarz for spotting the problem.
11 Oct 2006
25 Sep 2006
  • Updated some links and contact points listed in the Applications Software section of the CGNS Overview and Entry-Level Document.
5 Sep 2006
  • In the CGNS Steering Committee Charter,
  • In the Mid-Level Library, modified the description of the size argument for the Zone Information routines, attempting to clarify the definition for unstructured grids.
  • In the SIDS,
    • Modified the description of VertexSize for the Zone_t structure to clarify its definition for unstructured grids.
    • Modified the description of the GridConnectivity_t structure to allow GridLocation to be either Vertex or FaceCenter for Abutting and Abutting1to1 interfaces.
8 Aug 2006
  • Posted minutes from the Aug 2 CGNS Steering Committee telecon. (HTML, PDF).
28 July 2006
14 June 2006
  • Added slides from the special "CGNS Tutorial Session" at the 36th AIAA Fluid Dynamics Conference in San Francisco, California, June 5-8, 2006.
17 May 2006
  • Posted minutes from the May 10 CGNS Steering Committee telecon. (HTML, PDF).
13 Apr 2006
10 Apr 2006
  • Updated some links and contact points listed in the Applications Software section of the CGNS Overview and Entry-Level Document.
27 Mar 2006
1 Mar 2006
3 Feb 2006
  • In the Mid-Level Library Manual, corrected a typo in the name of the Fortran routine cg_array_read_as_f, used to read data arrays (the "_f" was left off).
17 Jan 2006
  • Updated (and alphabetized) the list of current member organizations in the CGNS Steering Committee Charter.
  • Posted minutes from the Jan 11 CGNS Steering Committee meeting. (HTML, PDF).
10 Jan 2006
  • Corrected a typo in the PDF version of the SIDS document involving an escaped underscore. Thanks to Marc Poinot for spotting it.
21 Dec 2005
15 Dec 2005
  • In the SIDS document,
    • Added a paragraph at the start of the Introduction intended to better explain the importance and benefits of using CGNS.
    • Added a bit to the description of the RotatingCoordinates_t data structure to more clearly explain its use, and deleted the sentence saying that it doesn't cover cases where the zone interfaces are not perpendicular to the axis of rotation.
    • Made a few other changes in various places to correct typos and add clarification.
    Thanks to Kurt Weber for his review of the updated AIAA Recommended Practice, and for suggesting these changes.
7 Dec 2005
21 Nov 2005
  • Eliminated most usage of images for equation elements throughout the HTML version of the CGNS documentation, in favor of the appropriate HTML character entities. E.g., instead of using a GIF image to represent the Greek letter rho, the character entity ρ is used instead. Images were originally used because HTML browsers typically didn't support character entities for many of the symbols that were used. Current-generation browsers, however, are much better. Mozilla Firefox 1.0.7 supports all the character entities used in the CGNS documentation, and Microsoft Internet Explorer 6.0 supports all but a couple. See the list of standard HTML 4.0 character entities for Symbols and Greek Letters external link to see how they are displayed in your browser.
17 Nov 2005
  • Corrected typos in the Solution Data section of the Mid-Level Library manual. (GridLocation_t was mistakenly written as GridLocationType_t.)
16 Nov 2005
  • Corrected a minor cross-referencing error in the PDF version of the SIDS document.
2 Nov 2005
  • In the description of the Generalized Connectivity routines in the Mid-Level Library Manual, clarified the definitions of ndata_donor and donor_data.
19 Oct 2005
18 Oct 2005
  • Added a couple of sentences in the Multizone Interface Connectivity and Boundary Conditions sections of the SIDS document to clarify that a given zone boundary segment is intended to be defined as either a boundary condition segment or a multizone connectivity segment, but not both.
17 Oct 2005
  • Updated the Elements and Documentation section of the Overview and Entry-Level Document to reflect the option of using HDF instead of ADF. (Thanks to Chris Rumsey for doing the update.)
5 Oct 2005
  • Posted minutes from the Oct 4 CGNS Steering Committee telecon. (HTML, PDF).
  • Added ERF Paper 31-107, titled "Application of CGNS software components for helicopter blade fluid-structure strong coupling," by M. Poinot, M. Costes, and B. Cantaloube, presented at the 31st European Rotorcraft Forum, Florence, Italy. [PDF (174K, 10 pages)]
7 Sep 2005
  • In the History section of the Overview document, added a sentence crediting ONERA, ICEM CFD, and AEDC for the addition of support for HDF5.
6 Sep 2005
23 Aug 2005
  • Posted slides CFD General Notation System, an overview of the CGNS project and its current status, presented by Bruce Wedan of ANSYS/ICEM CFD at NASA Ames, Jan 2005. [PowerPoint (345K, 46 pages)].
  • In the Mid-Level Library manual, added a paragraph to the description of the function cg_bcdata_write about writing the boundary condition data itself.
14 Jul 2005
20 Jun 2005
6 Jun 2005
  • Posted minutes from the May 25 CGNS Steering Committee telecon. (HTML, PDF).
27 May 2005
  • Updated some links and contact points listed in the Applications Software section of the CGNS Overview and Entry-Level Document.
26 May 2005
  • Modified the Organization/Bylaws section of the CGNS Steering Committee Charter to allow the appointment of a Vice-Chairperson.
22 Mar 2005
  • Posted minutes from the Mar 16 CGNS Steering Committee telecon. (HTML, PDF).
4 Feb 2005
  • Added AIAA Paper 2005-1381, titled "Benchmarking Parallel I/O Performance for Computational Fluid Dynamics Applications," by P. D. Pakalapati and T. Hauser, presented at the 43rd AIAA Aerospace Sciences Meeting and Exhibit. [PDF (3.6M, 8 pages)]
24 Jan 2005
  • Corrected an error in the Mid-Level Library manual, in the description of the data conversion routines cg_conversion_write and cg_conversion_read. The scale and offset factors are stored in a two-element array, not as separate scalars.
  • Corrected an error in the SIDS document, in the Elements_t data structure examples. The examples included DataArray_t data structures defining ParentData for 3-D elements, where it doesn't apply.
  • In the list of CGNS-related conference papers, added R. Magnan as an author for AIAA Paper 2005-0334. Apologies for inadvertantly omitting him in the original update.
19 Jan 2005
  • Added AIAA Paper 2005-0334, titled "CGNS-Based Data Model for Turbine Blade Optimization," by H. Iepan, F. Guibault, M.-G. Vallet, and R. Magnan, presented at the 43rd AIAA Aerospace Sciences Meeting and Exhibit. [PDF (379K, 11 pages)]
18 Jan 2005
  • Posted minutes from the Jan 12 CGNS Steering Committee meeting. (HTML, PDF).
  • Added AIAA Paper 2005-1155, titled "Checking CFD interfaces in a multi-disciplinary workflow with an XML/CGNS compiler" by M. Poinot, E. Montreuil, and E. Henaux, presented at the 43rd AIAA Aerospace Sciences Meeting and Exhibit. [PDF (662K, 11 pages)]
19 Nov 2004
  • Corrected (as Marc Poinot put it) the "smallest typo ever known", in the "Deforming Grid Motion" example in the Time-Dependent Flow section of the SIDS document. Thanks to Marc for spotting this.
  • Modified the Steering Committee Charter to add Utah State University, Stanford University, and ANSYS-CFX as Steering Committee members.
  • Posted minutes from the Nov 17 CGNS Steering Committee telecon. (HTML, PDF).
20 Oct 2004
  • Corrected an error in the section on Unstructured Grid Element Numbering Conventions in the SIDS document. For pyramid elements, the oriented edges for face F4 were listed as E6,E8,-E7, and the correct values are E3,E8,-E7. Thanks to Alan Sayre for spotting this.
6 Oct 2004
30 Sep 2004
  • Posted minutes from the Sep 28 CGNS Steering Committee telecon. (HTML, PDF).
29 Sep 2004
7 Jul 2004
  • Posted minutes from the June 30 CGNS Steering Committee meeting. (HTML, PDF).
  • Added AIAA Paper 2004-2142, titled "Impact of CGNS on CFD Workflow" by M. Poinot, C. L. Rumsey, and M. Mani, presented at the 34th AIAA Fluid Dynamics Conference and Exhibit. [PDF (729K, 12 pages)]
22 Jun 2004
  • Added AIAA Paper 2004-1088, titled "Parallel I/O for the CGNS system" by Th. Hauser, presented at the 42nd AIAA Aerospace Sciences Meeting and Exhibit. [PDF (1.5M, 11 pages)]
2 Jun 2004
  • Removed the wording "in the same manner as grid connectivity" in the description of the BC_t node in the SIDS-to-ADF File Mapping Manual, that was inadvertantly left in when the documentation was updated with the release of CGNS Version 2.3.
18 May 2004
  • Changed the description of Ordinal in the Mid-Level Library manual to say that it may be any integer value, and is not limited to values > 0.
2 Apr 2004
  • Posted minutes from the Mar 25 CGNS Steering Committee telecon. (HTML, PDF).
26 Mar 2004
19 Mar 2004
  • Removed the web page showing access stats for the CGNS documentation web pages. The widespread use of indexing robots for search engines, and the local use of link validation tools, have made the access stats pretty meaningless.
13 Feb 2004
  • Changed the description of the BC_t data structure in the SIDS manual to reflect the addition of ElementRange and ElementList.
  • In the Mid-Level Library manual, modified the description of the routines related to the Boundary Condition Type and Location to reflect the addition of ElementRange and ElementList in the BC_t structure.
  • In the File Mapping manual, modified the BC_t figure to reflect the addition of ElementRange and ElementList.
  • In the User's Guide to CGNS, modified the "Getting Started" section to reflect the addition of ElementRange and ElementList in the BC_t structure.
29 Jan 2004
  • Changed names of some .gif files used in the HTML version of the SIDS document, to avoid file name conflicts on Windows systems, which (unfortunately) uses case-insensitive file names.
13 Jan 2004
24 Nov 2003
  • Posted minutes from the Nov 20 CGNS Steering Committee telecon. (HTML, PDF).
24 Sep 2003
  • Posted minutes from the Sep 18 CGNS Steering Committee telecon. (HTML, PDF).
12 Sep 2003
  • Corrected typos in the Grid Connectivity section of the Mid-Level Library manual. (GridLocation_t was mistakenly written as GridLocationType_t.)
4 Jun 2003
2 Jun 2003
  • Posted minutes from the May 29 CGNS Steering Committee telecon. (HTML, PDF).
20 May 2003
13 May 2003
29 Apr 2003
  • Added site maps for the major CGNS documents.
23 Apr 2003
  • A search capability has been added. Words and/or phrases may be searched for in a specific document, or in all documents combined.
27 Mar 2003
  • Added a paragraph about the CGNStalk mailing list, with a link to the list archive.
  • Modified the description of cg_goto in the Mid-Level Library manual to note that when accessing a BCData_t node, the index must be set to either Dirichlet or Neumann.
26 Mar 2003
  • Posted minutes from the Mar 20 CGNS Steering Committee telecon. (HTML, PDF).
20 Mar 2003
  • Added a sentence to the description of the ZoneBC_t data structure in the SIDS document to clarify that each boundary condition patch must be represented by a single BC_t data structure.
  • Expanded Note 2 for the BC_t data structure in the SIDS document, to add some discussion about the interpretation of the points defining a BC patch when GridLocation is set to Vertex.
28 Jan 2003
23 Jan 2003
22 Jan 2003
15 Jan 2003
  • Posted minutes from the Jan 6 CGNS Steering Committee meeting. (HTML, PDF).
10 Dec 2002
6 Dec 2002
  • Posted minutes from the Dec 4 CGNS Steering Committee telecon. (HTML, PDF).
26 Sep 2002
25 Sep 2002
20 Sep 2002
12 Sep 2002
6 Sep 2002
23 Aug 2002
20 Aug 2002
12 Aug 2002
  • In the PDF version of the Mid-Level Library manual, corrected error in the input/output labeling for fn in the cg_open, cg_version, and cg_close routines.
30 Jul 2002
  • Updated the Overview document to reflect the release of Version 2.1 of the CGNS software on May 24, 2002.
3 Jul 2002
  • Posted slides presented by John Steinbrenner of Pointwise, Inc., at the 8th International Conference on Numerical Grid Generation in Honolulu, Hawaii, June 2-6, 2002. [PDF (131K, 12 pages), PowerPoint (143K, 12 pages)].
2 Jul 2002
  • Posted minutes from the June 24 CGNS Steering Committee meeting. (HTML, PDF).
31 May 2002
23 May 2002
  • Corrected a minor error in the OversetHoles_t structure definition. PointRange and PointList are not both optional; one must be specified, but not both.
22 May 2002
  • Posted minutes from the May 15 CGNS Steering Committee telecon. (HTML, PDF).
20 May 2002
7 May 2002
  • Added the document version number and the applicable CGNS software release number to the home or title page for each of the CGNS documents. Also added the CGNS logo, and in the HTML version changed the heading color to match the logo.
  • Updated and reorganized the Overview and Entry-Level Document.
  • Modified the definition of NormalListFlag for the Boundary Condition Type and Location routines in the Mid-Level Library manual.
  • Added a list summarizing the change history for the CGNS documentation.
25 Mar 2002
20 Mar 2002
  • Posted minutes from the Mar 13 CGNS Steering Committee telecon. (HTML, PDF).
15 Mar 2002
13 Mar 2002
11 Mar 2002
  • Changed the three non-PDF slide presentations to PDF files, supplied by Diane Poirier. (Thanks, Diane!)
6 Mar 2002
  • Added a page with the monthly access statistics for the CGNS documentation web site.
14 Feb 2002
5 Feb 2002
4 Feb 2002
  • Changed the attachments to the minutes from the Jan 14 CGNS Steering Committee meeting to PDF files, supplied by Diane Poirier. (Thanks, Diane!)
31 Jan 2002
25 Jan 2002
  • Added AIAA Paper 2002-0752, titled "CFD General Notation System (CGNS): Status and Future Directions", presented at the 40th AIAA Aerospace Sciences Meeting and Exhibit. [PDF (289K, 13 pages)]
23 Jan 2002
14 Nov 2001
2 Nov 2001
1 Nov 2001
10 Oct 2001
26 Sep 2001
17 Sep 2001
6 Sep 2001
23 Aug 2001
21 Aug 2001
10 Jul 2001
  • In the Mid-Level Library manual, changed to a slanted red font for the output variables, to better distinguish them from the input variables.
27 Jun 2001
  • Corrected a minor bug in the Flow Solution Example in the SIDS manual. The nondimensionalization factor for the momentum in the example is sqrt(p*rho), not sqrt(p/rho), and the corresponding ConversionScale values for MomentumX and MomentumY are both 352.446.
17 Apr 2001
5 Apr 2001
14 Mar 2001
  • In the SIDS manual, added statements in the sections describing the BaseIterativeData_t and ZoneIterativeData_t data structures clarifying that iterative data stored in a CGNS database corresponds to values at the end of the associated iteration.
7 Mar 2001
  • In the SIDS manual, added a statement in the 2-D (Surface) Elements subsection clarifying the normal direction for 2-D unstructured grid elements.
  • In the SIDS manual, added a statement in the section on data-name identifiers for flowfield variables stating that for vector quantities, data-name identifiers for components in cylindrical and spherical coordinates are established, even when they're not explicitly listed.
6 Mar 2001
  • Included software change history in this "What's New?" page.
22 Feb 2001