TiledColumnStMan.h
Classes
- TiledColumnStMan -- Tiled Column Storage Manager. (full description)
Interface
- Public Members
- TiledColumnStMan (const String& hypercolumnName, const IPosition& tileShape, uInt maximumCacheSize = 0)
- TiledColumnStMan (const String& hypercolumnName, const Record& spec)
- ~TiledColumnStMan()
- virtual DataManager* clone() const
- virtual Bool canAccessColumn (Bool& reask) const
- virtual String dataManagerType() const
- virtual Record dataManagerSpec() const
- static DataManager* makeObject (const String& dataManagerType, const Record& spec)
- Private Members
- TiledColumnStMan()
- void addRow (uInt nrrow)
- virtual TSMCube* getHypercube (uInt rownr)
- virtual TSMCube* getHypercube (uInt rownr, IPosition& position)
- virtual void setupCheck (const TableDesc& tableDesc, const Vector<String>& dataNames) const
- virtual Bool flush (AipsIO&, Bool fsync)
- virtual void create (uInt nrrow)
- virtual void readHeader (uInt nrrow, Bool firstTime)
Prerequisite
Etymology
TiledColumnStMan is the Tiled Storage Manager storing
an entire column as one hypercube.
Synopsis
TiledColumnStMan 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.
TiledColumnStMan allows the user to create a tiled hypercube for
an entire data column and extend it in an automatic way.
It is meant to be used for fixed shaped data which have to
be accessed in various directions.
The TiledColumnStMan has the following (extra) properties:
- Addition of a row results in the extension of the hypercube.
The data cells in all rows have to have the same shape. Therefore
the columns stored by a TiledColumnStMan storage manager
have to be fixed shaped (i.e. FixedShape attribute set in their
column descriptions).
- 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 extendHypercube call like in
TiledDataStMan).
- The tile shape of the hypercube has to be defined by means
of the TiledColumnStMan constructor.
Motivation
This tiled storage manager does not require any special action
(like calling add/extendHypercube) when used with a column
containing equally 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 (ScalarColumnDesc<float> ("Velocity"));
td.addColumn (ArrayColumnDesc<float> ("Image", 2));
// Define the 3-dim hypercolumn with its data and coordinate columns.
// Note that its dimensionality must be one higher than 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("tTiledColumnStMan_tmp.data", td, Table::New);
// Create a TiledColumnStMan storage manager for the hypercolumn
// and bind the columns to it.
// The tile shape has to be specified for the storage manager.
TiledColumnStMan sm1 ("TSMExample", IPosition(3,16,32,32));
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);
indgen (raValues);
indgen (decValues, float(100));
ArrayColumn<float> ra (table, "RA");
ArrayColumn<float> dec (table, "Dec");
ScalarColumn<float> velocity (table, "Velocity");
ArrayColumn<float> image (table, "Image");
Cube<float> imageValues(IPosition(2,512,512));
indgen (imageValues);
// Write some data into the data columns.
uInt i;
for (i=0; i<64; i++) {
table.addRow();
image.put (i, imageValues);
// The RA and Dec have to be put only once, because they
// are the same for each row.
if (i == 0) {
ra.put (i, raValues);
dec.put (i, decValues);
}
velocity.put (i, float(i));
}
Member Description
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.
The given maximum cache size in bytes (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.
Clone this object.
It does not clone TSMColumn objects possibly used.
virtual Bool canAccessColumn (Bool& reask) const
TiledColumnStMan can always access a column.
Get the type name of the data manager (i.e. TiledColumnStMan).
Record a record containing data manager specifications.
Make the object from the type name string.
This function gets registered in the DataManager "constructor" map.
Create a TiledColumnStMan.
This constructor is private, because it should only be used
by makeObject.
void addRow (uInt nrrow)
Add rows to the storage manager.
This will extend the hypercube.
Get the hypercube in which the given row is stored.
Get the hypercube in which the given row is stored.
It also returns the position of the row in that hypercube.
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.