TiledCellStMan.h

TiledCellStMan is a derivation from TiledStMan, the abstract tiled storage manager class. A description of the basics of tiled storage managers is given in the Tables module description.

TiledCellStMan allows the user to create a tiled hypercube for each data cell in an automatic way. It is meant to be used for storing regularly shaped data like images (where the table contains a possibly differently shaped image in each row).

The TiledCellStMan has the following (extra) properties:

Addition of a row results in the addition of a hypercube in which the data cells in that row will be stored. Thus each row of the hypercolumn is stored in its own hypercube. Note that a hypercolumn has a given dimensionality, so each data cell in the hypercolumn has to match that dimensionality.
Although there are multiple hypercubes, an id value is not needed. The row number serves as the id value.
Coordinates for the hypercubes can be defined and (of course) their shapes have to match the hypercube shape. Their values have to be put explicitly (so it is not possible to define them via an addHypercube call like in TiledDataStMan).
It is possible to define a (default) tile shape in the TiledCellStMan constructor. When setting the shape of the array in a row (using ArrayColumn::setShape), it is possible to override that default for the hypercube in this particular row.

Motivation

This tiled storage manager does not require any special action (like calling add/extendHypercube) when used with a column containing variable shaped arrays.

Example

  // Define the table description and the columns in it.
  TableDesc td ("", "1", TableDesc::Scratch);
  td.addColumn (ArrayColumnDesc<float>  ("RA", 1));
  td.addColumn (ArrayColumnDesc<float>  ("Dec", 1));
  td.addColumn (ArrayColumnDesc<float>  ("Velocity", 1));
  td.addColumn (ArrayColumnDesc<float>  ("Image", 3));
  // Define the 3-dim hypercolumn with its data and coordinate columns.
  // Note that its dimensionality must match the dimensionality
  // of the data cells.
  td.defineHypercolumn ("TSMExample",
			  3,
			  stringToVector ("Image"),
			  stringToVector ("RA,Dec,Velocity"));
  // Now create a new table from the description.
  SetupNewTable newtab("tTiledCellStMan_tmp.data", td, Table::New);
  // Create a TiledCellStMan storage manager for the hypercolumn
  // and bind the columns to it.
  TiledCellStMan sm1 ("TSMExample");
  newtab.bindAll (sm1);
  // Create the table.
  Table table(newtab);
  // Define the values for the coordinates of the hypercube.
  Vector<float> raValues(512);
  Vector<float> DecValues(512);
  Vector<float> VelocityValues(64);
  indgen (raValues);
  indgen (decValues, float(100));
  indgen (velocityValues, float(200));
  ArrayColumn<float> ra (table, "RA");
  ArrayColumn<float> dec (table, "Dec");
  ArrayColumn<float> velocity (table, "Velocity");
  ArrayColumn<float> image (table, "Image");
  Cube<float> imageValues(IPosition(3,512,512,64));
  indgen (imageValues);
  // Write some data into the data columns.
  uInt i;
  for (i=0; i<4; i++) {
      table.addRow();
	image.put (i, imageValues);
      ra.put (i, raValues);
      dec.put (i, decValues);
      velocity.put (i, velocityValues);
  }

Member Description

TiledCellStMan (const String& hypercolumnName, const IPosition& defaultTileShape, uInt maximumCacheSize = 0)
TiledCellStMan (const String& hypercolumnName, const Record& spec)

Create a TiledDataStMan storage manager for the hypercolumn with the given name. The columns used should have the FixedShape attribute set. The hypercolumn name is also the name of the storage manager. The given tile shape will be used as the default for the hypercube in each cell. Per cell it can be redefined via ArrayColumn::setShape. The given maximum cache size (default is unlimited) is persistent, thus will be reused when the table is read back. Note that the class ROTiledStManAccessor allows one to overwrite the maximum cache size temporarily. Its description contains a discussion about the effects of setting a maximum cache.
The constructor taking a Record expects fields in the record with the name of the arguments in uppercase. If not defined, their default value is used.

~TiledCellStMan()

DataManager* clone() const

Clone this object. It does not clone TSMColumn objects possibly used.

String dataManagerType() const

Get the type name of the data manager (i.e. TiledCellStMan).

Bool canChangeShape() const

This tiled storage manager can handle changing array shapes.

virtual void setShape (uInt rownr, TSMCube* hypercube, const IPosition& shape, const IPosition& tileShape)

Set the shape and tile shape of the hypercube.

static DataManager* makeObject (const String& dataManagerType, const Record& spec)

Make the object from the type name string. This function gets registered in the DataManager "constructor" map.

TiledCellStMan()

Create a TiledCellStMan. This constructor is private, because it should only be used by makeObject.

TiledCellStMan (const TiledCellStMan&)

Forbid copy constructor.

TiledCellStMan& operator= (const TiledCellStMan&)

Forbid assignment.

virtual IPosition defaultTileShape() const

Get the default tile shape.

void addRow (uInt nrrow)

Add rows to the storage manager.

virtual TSMCube* getHypercube (uInt rownr)

Get the hypercube in which the given row is stored.

virtual TSMCube* getHypercube (uInt rownr, IPosition& position)

Get the hypercube in which the given row is stored. It also returns the position of the row in that hypercube.

virtual void setupCheck (const TableDesc& tableDesc, const Vector<String>& dataNames) const

Check if the hypercolumn definition fits this storage manager.

virtual Bool flush (AipsIO&, Bool fsync)

Flush and optionally fsync the data. It returns a True status if it had to flush (i.e. if data have changed).

virtual void create (uInt nrrow)

Let the storage manager create files as needed for a new table. This allows a column with an indirect array to create its file.

virtual void readHeader (uInt nrrow, Bool firstTime)

Read the header info.