bdf/utils Package

This is the pyNastran.bdf.rst file.

utils Module

Defines various utilities for BDF parsing including:

• to_fields
• parse_patran_syntax
• parse_patran_syntax_dict
• Position
• PositionWRT
• TransformLoadWRT

exception pyNastran.bdf.utils.CardParseSyntaxError

Class that is used for testing. Users should just treat this as a SyntaxError.

pyNastran.bdf.utils.Position(xyz, cid, model, is_cid_int=True)

Gets the point in the global XYZ coordinate system.

Parameters:

• xyz (TYPE = NDARRAY. SIZE=(3,)) – the position of the GRID in an arbitrary coordinate system
• cid (int) – the coordinate ID for xyz
• model (BDF()) – the BDF model object

Returns xyz2:

the position of the GRID in an arbitrary coordinate system

pyNastran.bdf.utils.PositionWRT(xyz, cid, cid_new, model, is_cid_int=True)

Gets the location of the GRID which started in some arbitrary system and returns it in the desired coordinate system

Parameters:

• xyz (TYPE = NDARRAY. SIZE=(3,)) – the position of the GRID in an arbitrary coordinate system
• cid (int) – the coordinate ID for xyz
• cid_new (int) – the desired coordinate ID
• model (BDF()) – the BDF model object

Returns xyz_local:  

the position of the GRID in an arbitrary coordinate system

pyNastran.bdf.utils.TransformLoadWRT(F, M, cid, cid_new, model, is_cid_int=True)

Transforms a force/moment from an arbitrary coordinate system to another coordinate system.

Parameters:

• Fxyz (TYPE = NDARRAY. SIZE=(3,)) – the force in an arbitrary coordinate system
• Mxyz (TYPE = NDARRAY. SIZE=(3,)) – the moment in an arbitrary coordinate system
• cid (int) – the coordinate ID for xyz
• cid_new (int) – the desired coordinate ID
• model (BDF()) – the BDF model object
• is_cid_int (bool) – is cid/cid_new an integer or a Coord object

Returns Fxyz_local:  

the force in an arbitrary coordinate system

Returns Mxyz_local:  

the force in an arbitrary coordinate system

pyNastran.bdf.utils._clean_comment(comment, end=-1)

Removes specific pyNastran comment lines so duplicate lines aren’t created.

param comment:the comment to possibly remove param end:lets you remove trailing characters (e.g. a ``

``; default=-1)

pyNastran.bdf.utils.clean_empty_lines(lines)

Removes leading and trailing empty lines don’t remove internally blank lines

pyNastran.bdf.utils.get_include_filename(card_lines, include_dir='')

Parses an INCLUDE file split into multiple lines (as a list).

Parameters:

• card_lines – the list of lines in the include card (all the lines!)
• include_dir – the include directory (default=’‘)

Returns filename:  

the INCLUDE filename

pyNastran.bdf.utils.parse_executive_control_deck(executive_control_lines)

Extracts the solution from the executive control deck

pyNastran.bdf.utils.parse_patran_syntax(node_sets)

Parses Patran’s syntax for compressing nodes/elements

Parameters:node_sets – the node_set to parse Returns nodes:list of integers

Patran has a short syntax of the form:

String	Output
“1 2 3”	[1, 2, 3]
“5:10”	[5, 6, 7, 8, 9, 10]
“12:20:2”	[12, 14, 16, 18, 20]

pyNastran.bdf.utils.parse_patran_syntax_dict(node_sets)

Parses Patran’s syntax for compressing nodes/elements

Parameters:node_sets – the node_set to parse Returns nodes:list of integers

node_sets = "e 1:3 n 2:6:2 Node 10:13"
data = parse_patran_syntax_dict(node_sets)
data = {
    'e'    : [1, 2, 3],
    'n'    : [2, 4, 6],
    'Node' : [10, 11, 12, 13],
}

Note

the identifier (e.g. “e”) must be used. Use parse_patran_syntax to skip the identifier.

Note

doesn’t support “1:#”

pyNastran.bdf.utils.print_filename(filename, relpath)

Takes a path such as C:/work/fem.bdf and locates the file using relative paths. If it’s on another drive, the path is not modified.

Parameters:filename – a filename string Returns filename_string:  a shortened representation of the filename

pyNastran.bdf.utils.to_fields(card_lines, card_name)

Converts a series of lines in a card into string versions of the field. Handles large, small, and CSV formatted cards.

Parameters:

• lines – the lines of the BDF card object
• card_name – the card_name -> ‘GRID’

Returns fields:

the string formatted fields of the card

Warning

this function is used by the reader and isn’t intended to be called by a separate process

>>> card_lines = []'GRID,1,,1.0,2.0,3.0']
>>> card_name = 'GRID'
>>> fields = to_fields(lines, card_name)
>>> fields
['GRID', '1', '', '1.0', '2.0', '3.0']

write_path Module

Defines following useful methods:

• write_include

pyNastran.bdf.write_path._split_path(abspath)

Takes a path and splits it into the various components.

This is a helper method for write_include

pyNastran.bdf.write_path.main()

pyNastran.bdf.write_path.write_include(filename, is_windows=True)

Writes a bdf INCLUDE file line given an imported filename.

Parameters:

• filename – the filename to write
• is_windows – Windows has a special format for writing INCLUDE files so the format for a BDF that will run on Linux and Windows is different. We could check the platform, but since you might need to change platforms, it’s an option (default=True)

For a model that will run on Linux:

..code-blocK:: python

fname = r’/opt/NASA/test1/test2/test3/test4/formats/pynastran_v0.6/pyNastran/bdf/model.inc’ write_include(fname, is_windows=False)

We want:

..code-blocK:: python

INCLUDE /opt/NASA/test1/test2/test3/test4/formats/pynastran_v0.6/

pyNastran/bdf/model.inc