open¶
-
baseband.gsb.base.
open
(name, mode='rs', **kwargs)[source] [edit on github]¶ Open GSB file(s) for reading or writing.
A GSB data set contains a text header file and one or more raw data files. When the file is opened as text, one gets a standard filehandle, but with methods to read/write timestamps. When it is opened as a binary, one similarly gets methods to read/write frames. Opened as a stream, the file is interpreted as a timestamp file, but raw files need to be given too. This allows access to the stream(s) as series of samples.
- Parameters
- namestr
Filename of timestamp or raw data file.
- mode{‘rb’, ‘wb’, ‘rt’, ‘wt’, ‘rs’, or ‘ws’}, optional
Whether to open for reading or writing, and as a regular text or binary file (for timestamps and data, respectively) or as a stream. Default: ‘rs’, for reading a stream.
- **kwargs
Additional arguments when opening the file as a stream.
- — For both reading and writing of streams :
- rawstr or (tuple of) tuple of str
Name of files holding payload data. A single file is needed for rawdump, and a tuple for phased. For a nested tuple, the outer tuple determines the number of polarizations, and the inner tuple(s) the number of streams per polarization. E.g.,
((polL1, polL2), (polR1, polR2))
for two streams per polarization. A single tuple is interpreted as streams of a single polarization.- sample_rate
Quantity
, optional Number of complete samples per second, i.e. the rate at which each channel of each polarization is sampled. If
None
, will be inferred assuming the frame rate is exactly 251.658240 ms.- samples_per_frameint, optional
Number of complete samples per frame. Can give
payload_nbytes
instead.- payload_nbytesint, optional
Number of bytes per payload, divided by the number of raw files. If both
samples_per_frame
andpayload_nbytes
areNone
,payload_nbytes
is set to2**22
(4 MB) for rawdump, and2**23
(8 MB) divided by the number of streams per polarization for phased.- nchanint, optional
Number of channels. Default: 1 for rawdump, 512 for phased.
- bpsint, optional
Bits per elementary sample, i.e. per real or imaginary component for complex data. Default: 4 for rawdump, 8 for phased.
- complex_databool, optional
Whether data are complex. Default:
False
for rawdump,True
for phased.- squeezebool, optional
If
True
(default) and reading, remove any dimensions of length unity from decoded data. IfTrue
and writing, accept squeezed arrays as input, and adds any dimensions of length unity.- — For reading only(see
GSBStreamReader
) - subsetindexing object or tuple of objects, optional
Specific components of the complete sample to decode (after possibly squeezing). If a single indexing object is passed, it selects (available) polarizations. If a tuple is passed, the first selects polarizations and the second selects channels. If the tuple is empty (default), all components are read.
- verifybool, optional
Whether to do basic checks of frame integrity when reading. The first frame of the stream is always checked. Default:
True
.- — For writing only(see
GSBStreamWriter
) - header0
GSBHeader
Header for the first frame, holding time information, etc. Can instead give keyword arguments to construct a header.
- **kwargs
If the header is not given, an attempt will be made to construct one with any further keyword arguments. If one requires to explicitly set the mode of the GSB stream, use
header_mode
. If not given, it will be ‘rawdump’ if only a single raw file is present, or ‘phased’ otherwise. SeeGSBStreamWriter
.
- Returns
- Filehandle
GSBFileReader
orGSBFileWriter
(binary), orGSBStreamReader
orGSBStreamWriter
(stream)