open¶
-
baseband.vdif.base.
open
(name, mode='rs', **kwargs) [edit on github]¶ Open VDIF file(s) for reading or writing.
Opened as a binary file, one gets a wrapped filehandle that adds methods to read/write a frame. Opened as a stream, the handle is wrapped further, with methods such as reading and writing to the file as if it were a stream of samples.
- Parameters
- namestr or filehandle, or sequence of str
File name, filehandle, or sequence of file names (see Notes).
- mode{‘rb’, ‘wb’, ‘rs’, or ‘ws’}, optional
Whether to open for reading or writing, and as a regular binary file or as a stream. Default: ‘rs’, for reading a stream.
- **kwargs
Additional arguments when opening the file as a stream.
- — For reading a stream(see
VDIFStreamReader
) - sample_rate
Quantity
, optional Number of complete samples per second, i.e. the rate at which each channel in each thread is sampled. If
None
(default), will be inferred from the header or by scanning one second of the file.- squeezebool, optional
If
True
(default), remove any dimensions of length unity from decoded data.- subsetindexing object or tuple of objects, optional
Specific components of the complete sample to decode (after possible squeezing). If a single indexing object is passed, it selects threads. If a tuple is passed, the first selects threads and the second selects channels. If the tuple is empty (default), all components are read.
- fill_valuefloat or complex, optional
Value to use for invalid or missing data. Default: 0.
- verifybool, optional
Whether to do basic checks of frame integrity when reading. The first frameset of the stream is always checked. Default:
True
.- — For writing a stream(see
VDIFStreamWriter
) - header0
VDIFHeader
Header for the first frame, holding time information, etc. Can instead give keyword arguments to construct a header (see
**kwargs
).- sample_rate
Quantity
Number of complete samples per second, i.e. the rate at which each channel in each thread is sampled. For EDV 1 and 3, can alternatively set
sample_rate
within the header.- nthreadint, optional
Number of threads (e.g., 2 for 2 polarisations). Default: 1.
- squeezebool, optional
If
True
(default), writer accepts squeezed arrays as input, and adds any dimensions of length unity.- file_sizeint or None, optional
When writing to a sequence of files, the maximum size of one file in bytes. If
None
(default), the file size is unlimited, and only the first file will be written to.- **kwargs
If the header is not given, an attempt will be made to construct one with any further keyword arguments. See
VDIFStreamWriter
.
Notes
One can also pass to
name
a list, tuple, or subclass ofFileNameSequencer
. For writing to multiple files, thefile_size
keyword must be passed or only the first file will be written to. One may also pass in asequentialfile
object (opened in ‘rb’ mode for reading or ‘w+b’ for writing), though for typical use cases it is practically identical to passing in a list or template.