VLBIFrameBase

class baseband.vlbi_base.frame.VLBIFrameBase(header, payload, valid=True, verify=True)

Bases: object

Representation of a VLBI data frame, consisting of a header and payload.

Parameters:

header : baseband.vlbi_base.header.VLBIHeaderBase

Wrapper around the encoded header words, providing access to the header information.

payload : VLBIPayloadBase

Wrapper around the payload, provding mechanisms to decode it.

valid : bool

Whether the data are valid. Default: True.

verify : bool

Whether to do basic verification of integrity. Default: True.

Notes

The Frame can also be instantiated using class methods:

fromfile : read header and payload from a filehandle

fromdata : encode data as payload

Of course, one can also do the opposite:

tofile : method to write header and payload to filehandle

data : property that yields full decoded payload

One can decode part of the payload by indexing or slicing the frame. If the frame does not contain valid data, all values returned are set to self.fill_value.

A number of properties are defined: shape and dtype are the shape and type of the data array, and nbytes the frame size in bytes. Furthermore, the frame acts as a dictionary, with keys those of the header. Any attribute that is not defined on the frame itself, such as .time will be looked up on the header as well.

Attributes Summary

data	Full decoded frame.
dtype	Numeric type of the frame data.
fill_value	Value to replace invalid data in the frame.
nbytes	Size of the encoded frame in bytes.
ndim	Number of dimensions of the frame data.
sample_shape	Shape of a sample in the frame (nchan,).
shape	Shape of the frame data.
size	Total number of component samples in the frame data.
valid	Whether frame contains valid data.

Methods Summary

fromdata(data, header, *args, **kwargs)	Construct frame from data and header.
fromfile(fh, *args, **kwargs)	Read a frame from a filehandle.
keys()
tofile(fh)	Write encoded frame to filehandle.
verify()	Simple verification.

Attributes Documentation

data

Full decoded frame.

dtype

Numeric type of the frame data.

fill_value

Value to replace invalid data in the frame.

nbytes

Size of the encoded frame in bytes.

ndim

Number of dimensions of the frame data.

sample_shape

Shape of a sample in the frame (nchan,).

shape

Shape of the frame data.

size

Total number of component samples in the frame data.

valid

Whether frame contains valid data.

Methods Documentation

classmethod fromdata(data, header, *args, **kwargs)

Construct frame from data and header.

Parameters:

data : ndarray

Array holding data to be encoded.

header : VLBIHeaderBase

Header for the frame.

*args, **kwargs :

Any arguments beyond the filehandle are used to help initialize the payload, except for valid and verify, which are passed on to the header and class initializers.

classmethod fromfile(fh, *args, **kwargs)

Read a frame from a filehandle.

Any arguments beyond the filehandle are used to help initialize the payload, except for valid and verify, which are passed on to the header and class initializers.

keys()

tofile(fh)

Write encoded frame to filehandle.

verify()

Simple verification. To be added to by subclasses.