`cape.cgns`: CGNS file interface¶

This module provides a class for reading CGNS files of certain types that have been implemented. The main purpose is to read surface triangulations with quads and convert it into a cape.tri.Tri object. However, the class provided in this module, cape.cgns.CGNS, must be converted into a cape.tri.Tri or other object externally. This module merely reads the file, reads the data from each node, and constructs a sub-node table.

In order to create a triangulation interface from a CGNS file, see cape.tri.Tri, and use the cgns keyword argument.

cape.cgns.ADFAddress2Pos(addr)¶

Convert ADF 12-byte code into position index

This is a hex code with but skipping the 8th character

Call:

>>> pos = ADFAddress2Pos(addr)

Inputs:

addr: str: 12-character string hex code

Outputs:

pos: int: Position in file in bytes

Versions:

2018-03-02 @ddalle: Version 1.0

class cape.cgns.CGNS(fname)¶

Interface to CGNS files

Call:

>>> cgns = cape.cgns.CGNS(fname)

Inputs:

fname: str: Name of CGNS file

Outputs:

cgns: cape.cgns.CGNS: CGNS file interface
cgns.nNode: int: Number of nodes read
cgns.NodeNames: np.ndarray[str]: Names of each node
cgns.NodeLabels: np.ndarray[str]: Labels for each node (often a data type holder)
cgns.NodeAddresses: np.ndarray[int]: File position of the beginning of each node
cgns.DataTypes: list (str): Data type for each node
cgns.Data: list[np.ndarray | str]: Data set for each node
cgns.SubNodeTables: list[list | None]: List of any child nodes for each node

Versions:

2018-03-02 @ddalle: Version 1.0

GetCompIDInfo(comp)¶

Get the info for a named zone with type Elements_t

Call:

>>> ka, kb, Elems = cgns.GetCompIDInfo(comp)
>>> ka, kb, Elems = cgns.GetCompIDInfo(addr)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
comp: str: Name of component to read
addr: int: Address of the node within the file

Outputs:

ka: int

Element index of the first element in comp (1-based)

kb: int

Element index of the last element in comp (1-based)

Elems: np.ndarray

shape: (nElem, nVert)

Array of vertex indices for each element

Versions:

2018-03-02 @ddalle: Version 1.0

GetNodeByAddress(addr)¶

Get index of node by explicit address (unique identifier)

Call:

>>> k = cgns.GetNodeByAddress(addr)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
addr: {None} | int: Address of the beginning of the node

Outputs:

k: int: Node index

Versions:

2018-03-02 @ddalle: Version 1.0

GetNodeIndex(name=None, label=None, addr=None)¶

Get index of a node by name and label or address

Call:

>>> K = cgns.GetNodeIndex(name=None, label=None, addr=None)
>>> K = cgns.GetNodeIndex(name)
>>> K = cgns.GetNodeIndex(name, label)
>>> K = cgns.GetNodeIndex(addr)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
name: {None} | str: Node name
label: { None} | str: Node label
addr: {None} | int: Address of the beginning of the node

Outputs:

k: np.ndarray[int]: Node index list

Versions:

2018-03-02 @ddalle: Version 1.0

GetSubNodeByLabel(k, label)¶

Get subnode by desired type

Call:

>>> J = cgns.GetSubNodeByLabel(k, label)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
k: int: Node index (0-based)
label: str: Desired label

Outputs:

J: np.ndarray[int]: List of such subnodes

Versions:

2018-03-02 @ddalle: Version 1.0

GetSubNodeByName(k, name)¶

Get subnode by desired name

Call:

>>> J = cgns.GetSubNodeByName(k, name)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
k: int: Node index (0-based)
name: str: Desired name

Outputs:

J: np.ndarray[int]: List of such subnodes

Versions:

2018-03-02 @ddalle: Version 1.0

ReadADF(f)¶

Read open CGNS/ADF file, currently at position 0

Call:

>>> cgns.ReadADF(f)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
f: file: Open file currently at the beginning of NoDe field

Versions:

2018-03-02 @ddalle: Version 1.0

ReadADFData(f, dt)¶

Read one DaTa entry from an open CGNS/ADF file

The next four bytes must be the string "DaTa", and the following 12 bytes must give the address of the end of the field as a hex code string.

Call:

>>> data = cgns.ReadADFData(f, dt)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
f: file: Open file currently at the beginning of DaTa field
dt: "MT" | "C1" | "I4" | "R4" | "R8": Data type, two-digit code

Outputs:

data: np.ndarray | str: Data read from file

Versions:

2018-03-02 @ddalle: Version 1.0

ReadADFFree(f)¶

Read one FreE entry from an open CGNS/ADF file

The next 4 bytes must be the string "FreE", and the following 12 bytes must give the address of the end of the field as a hex code string.

Call:

>>> cgns.ReadADFFreE(f)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
f: file: Open file currently at the beginning of DaTa field

Versions:

2018-03-05 @ddalle: Version 1.0

ReadADFNode(f)¶

Read a (new) node from an open CGNS/ADF file

Call:

>>> cgns.ReadADFNode(f)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
f: file: Open file currently at the beginning of NoDe field

Versions:

2018-03-02 @ddalle: Version 1.0

ReadADFSubNodeTable(f)¶

Read one SNTb entry from an open CGNS/ADF file

The next four bytes must be the string "SNTb", and the following 12 bytes must give the address of the end of the field as a hex code string.

Call:

>>> sntb = cgns.ReadADFSubNodeTable(f)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
f: file: Open file currently at the beginning of DaTa field

Outputs:

sntb: np.array[[str, int]]: List of name and begin addresses of any subnodes

Versions:

2018-03-02 @ddalle: Version 1.0

ReadADFZs(f)¶

Read strings like “zzzzzzzzzzzz” until a relevant char

Call:

>>> cgns.ReadADFZs(f)

Inputs:

cgns: cape.cgns.CGNS: CGNS file interface
f: file: Open file currently at the beginning of DaTa field

Versions:

2018-03-05 @ddalle: Version 1.0

`cape.cgns`: CGNS file interface¶

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`cape.cgns`: CGNS file interface¶