GridCoordEnum

Copyright 2021 Cadence Design Systems, Inc. All rights reserved worldwide.

A Glyph library that helps with the export of 2D or 3D grid data to an unstructured format.

Exporting grid data to an unstructured format requires the serial enumeration (1 to N) of all unique grid points. However, because Pointwise grid entites share points, non-trivial data management is needed to efficiently serialize the grid points. The pwio library provides the required data management.

The pwio library supports both structured and unstructured Pointwise grid entities. However, structured entities are exported as unstructured quads and hexes.

Limitations

• Support for 2D boundaries needs work
  • For more information, see the Access Cell Connectivity / Entity By Entity section.

Table Of Contents

• Namespace pwio
• Library Reference pwio
• The Export Sequence
• Example Usage
  • Access Grid Points
  • Access Cell Connectivity
    • Entity By Entity Access
    • Global Access
• Library Reference pwio::utils
• Library Reference pwio::cell
• Pointwise Cannonical Order
• Disclaimer

Namespace pwio

All of the procs in this collection reside in the pwio namespace.

To call a proc in this collection, you must prefix the proc name with a pwio:: namespace specifier.

For example:

pwio::beginIO $ents

Library Reference pwio

pwio::beginIO { ents }

Prepare a list of grid entities for export. Must be called once at the beginning of an export.

ents

The entities to export.

For a 2D grid, ents should contain pw::Domain entities.

For a 3D grid, ents should contain pw::Block entities.

---

pwio::endIO { {clearAllLocks 0} }

Cleans up after an export. Must be called once at the end of an export.

clearAllLocks

If 1, all entity locks will be released even if pwio did not make them.

Typically, clearAllLocks should be 0.

---

pwio::getCoordCount {}

Returns the number of unique grid points in this export.

---

pwio::getCoord { enumNdx }

Get an export grid coord.

enumNdx

The grid coord index from 1 to pwio::getCoordCount.

---

pwio::getCoordIndex { coord {mapCoordToOwner 1} }

Returns the index corresponding to a grid coord.

coord

The grid coord.

mapCoordToOwner

If 1, coord needs to be mapped to its owning entity.

If you know that the grid coord's entity is already the owner, this call is faster if you set mapCoordToOwner to 0.

---

pwio::getCellCount {}

Returns the number of unique, serialized grid cells in this export.

For a 2D grid, the cells will be of type tri or quad.

For a 3D grid, the cells will be of type tet, pyramid, prism, or hex.

---

pwio::getCell { enumNdx {vcVarName ""} }

Returns an export grid cell as a list of global pwio indices.

enumNdx

A grid cell index from 1 to pwio::getCellCount.

vcVarName

If provided, the cell's volume condition is stored in this variable.

The object stored in vcVarName is a pw::VolumeCondition.

---

pwio::getCellIndex { ent entNdx }

Returns the global, export cell index corresponding to an entity's local cell index.

ent

The grid entity.

entNdx

A cell index in ent's local index space.

---

pwio::getCellEdges { enumNdx {cellVarName ""} {minFirstOrder 0} {revVarName ""} }

Returns an export cell's edges as a list of global pwio indices.

enumNdx

A grid cell index from 1 to pwio::getCellCount.

cellVarName

If provided, this var receives the cell's indices.

minFirstOrder

If 1, edge indices are reversed, if needed, so that the minimum index value is first.

revVarName

If provided, this var receives a list of edge flags. A flag is set to 1 if the edge was min first reversed.

See also, pwio::getCell

---

pwio::getMinFirstCellEdges { enumNdx {cellVarName ""} {revVarName ""} }

Returns an export cell's edges as a list of global pwio indices in min first order.

enumNdx

A grid cell index from 1 to pwio::getCellCount.

cellVarName

If provided, this var receives the cell's indices.

revVarName

If provided, this var receives a list of edge flags. A flag is set to 1 if the edge was min first reversed.

See also, pwio::getCell

---

pwio::getFaceEdges { face {cellVarName ""} {minFirstOrder 0} {revVarName ""} }

Returns a list of face's edges. Each edge is a list of global pwio indices (a list of lists).

face

A face as a list of global pwio indices.

cellVarName

If provided, this var receives a copy of face.

minFirstOrder

If 1, edge indices are reversed, if needed, so that the minimum index value is first.

revVarName

If provided, this var receives a list of edge flags. A flag is set to 1 if the edge was min first reversed.

See also, pwio::getCellFaces

---

pwio::getMinFirstFaceEdges { face {cellVarName ""} {revVarName ""} }

Returns face's edges as a list of global pwio indices in min first order.

face

A face as a list of global pwio indices.

cellVarName

If provided, this var receives a copy of face.

revVarName

If provided, this var receives a list of edge flags. A flag is set to 1 if the edge was min first reversed.

See also, pwio::getCellFaces

---

pwio::getCellFaces { enumNdx {cellVarName ""} {minFirstOrder 0} }

Returns a list of a grid cell's faces. Each face is a list of global pwio indices (a list of lists).

enumNdx

The grid cell index from 1 to pwio::getCellCount.

cellVarName

If provided, this var receives the cell's unmodified indices.

minFirstOrder

If 1, the face indices are rotated so that the minimum index value is first. The relative ordering of the vertices is not changed (the face normal is not flipped).

See also, pwio::getCell.

---

pwio::getMinFirstCellFaces { enumNdx {cellVarName ""} }

Returns a list of a grid cell's faces in min first order. Each face is a list of global pwio indices (a list of lists).

enumNdx

The grid cell index from 1 to pwio::getCellCount.

cellVarName

If provided, this var receives the cell's unmodified indices.

See also, pwio::getCell.

---

pwio::getCellType { enumNdx }

Returns the grid cell's type.

enumNdx

The grid cell index from 1 to pwio::getCellCount.

For a 2D grid, the cell type will be one tri or quad.

For a 3D grid, the cell type will be one tet, pyramid, prism, or hex.

---

pwio::getFaceType { face }

Returns the face type.

face

A face as a list of global pwio indices.

For a 2D grid, the face type will be bar.

For a 3D grid, the face type will be one tri or quad.

See also, pwio::getCellFaces.

---

pwio::getEntityCell { ent ndx {localCellVarName ""} }

Returns an entity cell as a list of global pwio indices. These indices are only valid for calls to pwio::getCoord.

ent

The grid entity.

ndx

The cell index in ent's local index space.

localCellVarName

If provided, this var receives the cell's local indices.

---

pwio::getEntityCellEdges { ent ndx {cellVarName ""} {minFirstOrder 0} {revVarName ""} }

Returns an entity cell's edges as a list of global pwio indices. These indices are only valid for calls to pwio::getCoord.

ent

The grid entity.

ndx

The cell index in ent's local index space.

cellVarName

If provided, this var receives the cell's indices.

minFirstOrder

If 1, edge indices are reversed, if needed, so that the minimum index value is first.

revVarName

If provided, this var receives a list of edge flags. A flag is set to 1 if the edge was min first reversed.

See also, pwio::getCell.

---

pwio::getMinFirstEntityCellEdges { ent ndx {cellVarName ""} {revVarName ""} }

Returns an entity cell's edges as a list of global pwio indices in min first order. These indices are only valid for calls to pwio::getCoord.

ent

The grid entity.

ndx

The cell index in ent's local index space.

cellVarName

If provided, this var receives the cell's indices.

revVarName

If provided, this var receives a list of edge flags. A flag is set to 1 if the edge was min first reversed.

See also, pwio::getCell.

---

pwio::getCaeDim {}

Returns 2 if the grid dimensionality is 2D or 3 if the grid dimensionality is 3D.

---

pwio::getSelectType {}

Returns Domain if the grid dimensionality is 2D or Block if the grid dimensionality is 3D.

See pwio::utils::getSelection.

---

pwio::fixCoord { coordVarName }

Returns the grid coord corrected to use proper indexing form.

coordVarName

Required. The grid coord to be modifed if needed.

---

pwio::coordMapLower { coord }

Returns the grid coord mapped to its next lower level entity.

coord

The grid coord to be mapped.

---

pwio::mapToOwner { coord {trace 0} }

Returns the grid coord mapped to its owning entity.

coord

The grid coord to be mapped.

trace

For debugging only. If 1, the mapping sequence is dumped to stdout.

---

pwio::coordGetEntity { coord }

Returns the entity of the grid coord.

coord

The grid coord.

---

pwio::coordGetIjk { coord }

Returns the ijk index of the grid coord.

coord

The grid coord.

---

pwio::Level

Enumerated entity level integer values.

Accessed as:

• pwio::Level::Block
• pwio::Level::Domain
• pwio::Level::Connector
• pwio::Level::Node

See also pwio::coordMapToLevel, and pwio::entGetLevel.

---

pwio::entGetLevel { entOrBaseType }

Returns an entity level value.

entOrBaseType

A grid entity or an entity base type.

See also, pwio::utils::entBaseType.

---

pwio::coordGetLevel { coord }

Returns an entity level value for the entity in the grid coord.

coord

The grid coord.

---

pwio::coordMapToEntity { fromCoord toEnt coordsVarName }

Returns non-zero if fromCoord can be mapped to a grid coord in toEnt.

fromCoord

The starting grid coord.

toEnt

The target grid entity.

coordsVarName

Required. Receives the list of mapped grid coords.

---

pwio::coordMapToLevel { coord toLevel coordsVarName }

Returns non-zero if coord can be mapped to a specific grid level.

coord

The starting grid coord.

toLevel

The target grid level.

coordsVarName

Required. Receives the list of mapped grid coords.

The Export Sequence

Exporting a grid using pwio requires the same basic sequence:

• Call pwio::beginIO with a list of entites to export.
  • A list of pw::Domain entites for a 2D export.
  • A list of pw::Block entites for a 3D export.
• Access the grid data using pwio and Glyph procs.
  • See the Example Usage section.
  • See the Pointwise Cannonical Order section.
• Call pwio::endIO when finished.

Example Usage

The following section show how to use pwio in conjuction with the standard Glyph calls.

While many formats have a lot in common, each export format will have differing needs. The usage examples given below will not be needed by every exporter.

Access Grid Points

pwio::beginIO $gridEntsToExport

# Get the number of unique grid points in $gridEntsToExport.
set coordCnt [pwio::getCoordCount]
for {set ii 1} {$ii <= $coordCnt} {incr ii} {
  # Get the grid coord for grid point $ii.
  set coord [pwio::getCoord $ii]

  # Get the physical xyz location of coord. The returned xyz is always in the
  # form {x y z}
  set xyz [pw::Grid getXYZ $coord]

  # Get the location of coord. If coord is database constrained, pt will be in
  # the form {u v dbentity}. If *not* database constrained, pt will be in the
  # form {x y z}.
  set pt [pw::Grid getPoint $coord]

  # Get grid entity that owns this coord.
  set ownerEnt [pw::Grid getEntity $coord]
}

pwio::endIO

Access Cell Connectivity

Entity By Entity Access

Accessing interior and boundary cell connectivity is done on an entity by entity basis.

pwio::beginIO $gridEntsToExport

# Access the top-level pw::Domain (2D) or pw::Block (3D) volume cells.
foreach ent $gridEntsToExport {
  # Get vc asigned to $ent
  set vc [$ent getVolumeCondition]
  # Get the number of cells in $ent.
  set cellCnt [$ent getCellCount]
  for {set ii 1} {$ii <= $cellCnt} {incr ii} {
    # Get $ent cell $ii as a list of global pwio indices. These indices are only
    # valid for calls to pwio::getCoord.
    set cell [pwio::getEntityCell $ent $ii]
  }
}

# Access the pw::Connector (2D) or a pw::Domain (3D) boundary cells.
set bcNames [pw::BoundaryCondition getNames]
foreach bcName $bcNames {
  set bc [pw::BoundaryCondition getByName $bcName]
  # Get the boundary grid entites using $bc. $bcEnts will contain
  # pw::Connector (2D) or a pw::Domain (3D) entities.
  set bcEnts [$bc getEntities]
  # See notes below about handling the boundary entities.
}

pwio::endIO

Properly handling the boundary entities is beyond the scope of this example.

Things to consider:

• Only items in $bcEnts that are used by $gridEntsToExport entities should be exported (connectors used by domains, domains used by blocks).
• When exporting 2D boundaries:
  • The pw::Connector (linear) cells are defined as two consecutive local connector points {0 1}, {1 2}, etc.
  • The local cell indices must be mapped to global pwio indices using pwio::getCoordIndex.
• When exporting 3D boundaries:
  • The pw::Domain boundary cells can be enumerated in a manner similar to the volume cells example.

Global Access

Like grid points, some export formats require the serial enumeration (1 to N) of all unique cells.

pwio::beginIO $gridEntsToExport

# Get the number of cells in $gridEntsToExport.
set cellCnt [pwio::getCellCount]
for {set ii 1} {$ii <= $cellCnt} {incr ii} {
  # Get grid cell $ii. cell is a list of grid coord indices.
  # These indices correspond to the coords returned by [pwio::getCoord $ii]
  set cell [pwio::getCell $ii vc]
}

pwio::endIO

Library Reference pwio::utils

Documentation for pwio::utils

Library Reference pwio::cell

Documentation for pwio::cell

Pointwise Cannonical Order

The cell and face lists returned by these procs arrange the indices in Pointwise cannonical order.

The ordering is defined as follows:

Disclaimer

This file is licensed under the Cadence Public License Version 1.0 (the "License"), a copy of which is found in the LICENSE file, and is distributed "AS IS." TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, CADENCE DISCLAIMS ALL WARRANTIES AND IN NO EVENT SHALL BE LIABLE TO ANY PARTY FOR ANY DAMAGES ARISING OUT OF OR RELATING TO USE OF THIS FILE. Please see the License for the full text of applicable terms.