#8 Add vdif-convert script

vdif-convert

@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+
+
+"""Convert VDIF to NumPy format.
+
+Usage: vdif-convert <vdif> [<npz>] [--chbin <N>]
+
+<vdif>        Input VDIF file (*.vdif).
+<npz>         Output NumPy file (*.npz).
+--chbin <N>   Number of channels to bin [default: 1].
+-h --help     Show this screen and exit.
+-v --version  Show version and exit.
+
+"""
+
+
+__author__ = "Akio Taniguchi"
+__version__ = "0.1.0"
+
+
+# standard library
+from pathlib import Path
+
+
+# dependencies
+import numpy as np
+from docopt import docopt
+from vdif_reader import get_all_spectra
+
+
+# main functions
+def main() -> None:
+    args = docopt(__doc__, version=__version__)
+
+    vdif = Path(args["<vdif>"]).resolve()
+
+    try:
+        npz = Path(args["<npz>"]).resolve()
+    except TypeError:
+        npz = vdif.with_suffix(".npz")
+
+    spectra = get_all_spectra(vdif, int(args["--chbin"]))
+    np.savez(npz, spectra=spectra)
+
+
+# run command line interface
+if __name__ == "__main__":
+    main()

vdif_reader.py

@@ -1,4 +1,8 @@
-__all__ = ["get_spectrum", "get_cal_spectrum"]
+__all__ = [
+    "get_spectrum",
+    "get_all_spectra",
+    "get_cal_spectrum",
+]
 
 
 # standard library
@@ -12,6 +16,7 @@
 
 # dependent packages
 import numpy as np
+from tqdm import tqdm
 
 
 # constants
@@ -53,6 +58,25 @@ def get_cal_spectrum(
     return get_spectrum(path, cal, delay, chbin)
 
 
+def get_all_spectra(path: Path, chbin: int = 1) -> np.ndarray:
+    n_units = path.stat().st_size // N_BYTES_PER_UNIT
+    n_scans = n_units // N_UNITS_PER_SCAN
+    n_chans = N_ROWS_CORR_DATA // 2
+
+    spectra = np.empty([n_units, n_chans], dtype=np.complex64)
+
+    with open(path, "rb") as f:
+        for i in tqdm(range(n_units)):
+            read_vdif_head(f)
+            read_corr_head(f)
+            corr_data = read_corr_data(f)
+            spectra[i] = parse_corr_data(corr_data)
+
+    n_chans = n_chans * N_UNITS_PER_SCAN
+    spectra = spectra.reshape([n_scans, n_chans])
+    return spectra.reshape([n_scans, n_chans // chbin, chbin]).mean(2)
+
+
 # sub features
 def get_spectra(path: Path, integ: float = 1.0, delay: float = 0.0) -> np.ndarray:
     n_scans = int(get_elapsed_time_from_start(path, delay) / TIME_PER_SCAN)