API¶
Contexts¶
Contexts are objects supplying information to implementers of Providers.
-
class
InitialisationContext
¶ Initialisation Context object passed to Providers.
It provides initialisation information to a Provider, allowing Providers to perform setup based on configuration.
class CustomSourceProvider(SourceProvider): def init(self, init_context): config = context.cfg() ...
-
cfg
¶ Configuration
-
-
class
StartContext
¶ Start Context object passed to Providers.
It provides information to the user implementing a data source about the extents of the data tile that should be provided.
# uvw varies by time and baseline and has 3 coordinate components cube.register_array("uvw", ("ntime", "nbl", 3), np.float64) ... class CustomSourceProvider(SourceProvider): def start(self, start_context): # Query dimensions directly (lt, ut), (lb, ub) = context.dim_extents("ntime", "nbl") ...
Public methods of a
HyperCube
are proxied on this object. Other useful information, such as the configuration, iteration space arguments are also present on this object.-
cfg
¶ Configuration
-
-
class
StopContext
¶ Stop Context object passed to Providers.
It provides information to the user implementing a data source about the extents of the data tile that should be provided.
# uvw varies by time and baseline and has 3 coordinate components cube.register_array("uvw", ("ntime", "nbl", 3), np.float64) ... class CustomSourceProvider(SourceProvider): def stop(self, stop_context): # Query dimensions directly (lt, ut), (lb, ub) = context.dim_extents("ntime", "nbl") ...
Public methods of a
HyperCube
are proxied on this object. Other useful information, such as the configuration, iteration space arguments are also present on this object.-
cfg
¶ Configuration
-
-
class
SinkContext
¶ Context object passed to data sinks.
Primarily, it exists to provide a tile of output data to the user.
class MySinkProvider(SinkProvider): vis_queue = Queue(10) ... def model_vis(self, context): print context.help(display_cube=True) # Consume data vis_queue.put(context.data)
Public methods of a
HyperCube
are proxied on this object. Other useful information, such as the configuration, iteration space arguments and the abstract array schema are also present on this object.-
array_schema
¶ The array schema of the array associated with this data source. For instance if model_vis is registered on a hypercube as follows:
# Register model_vis array_schema on hypercube cube.register_array("model_vis", ("ntime", "nbl", "nchan", "ncorr"), np.complex128) ... # Create a source context for model_vis data source context = SourceContext("model_vis", ...) ... # Obtain the array schema context.array_schema == ("ntime", "nbl", "nchan", "ncorr")
-
cfg
¶ Configuration
-
data
¶ The data tile available for consumption by the associated sink
-
help
(display_cube=False)¶ Get help associated with this context
Parameters: display_cube (bool) – Add hypercube description to the output Returns: A help string associated with this context Return type: str
-
input
¶ The dictionary of inputs used to produce
data
. For example, if one wished to find the antenna pair used to produce a particular model visibility, one could do the following:def model_vis(self, context): ant1 = context.input["antenna1"] ant2 = context.input["antenna2"] model_vis = context.data
-
iter_args
¶ Iteration arguments that describe the tile sizes over which iteration is performed. In the following example, iteration is occuring in tiles of 100 Timesteps, 64 Channels and 50 Point Sources.
context.iter_args == [("ntime", 100), ("nchan", 64), ("npsrc", 50)]
-
name
¶ The name of the data sink of this context.
-
Abstract Provider Classes¶
This is the Abstract Base Class that all Source Providers must inherit from.
Alternatively, the SourceProvider
class inherits from AbstractSourceProvider
and provides some useful concrete implementations.
This is the Abstract Base Class that all Sink Providers must inherit from.
Alternatively, the SinkProvider
class inherits from AbstractSinkProvider
and provides some useful concrete implementations.
-
class
AbstractSinkProvider
¶ -
clear_cache
()¶ Clears any caches associated with the sink
-
close
()¶ Perform any required cleanup
-
init
(init_context)¶ Called when initialising Providers
-
name
()¶ Returns this data sink’s name
-
sinks
()¶ Returns a dictionary of sink methods, keyed on sink name
-
start
(start_context)¶ Called at the start of any solution
-
stop
(stop_context)¶ Called at the end of any solution
-
Source Provider Implementations¶
Sink Provider Implementations¶
-
class
MSSinkProvider
¶ Sink Provider that receives model visibilities produced by montblanc
-
__init__
(manager, vis_column=None)¶ Constructs an MSSinkProvider object
Parameters: - manager (
MeasurementSetManager
) – TheMeasurementSetManager
used to access the Measurement Set. - vis_column (str) – Column to which model visibilities will be read
- manager (
-
model_vis
(context)¶ model visibility data sink
-
name
()¶ Returns this data sink’s name
-