# -*- coding: utf-8 -*-
from ast import literal_eval
import math
import re
import numpy as np
hour_re = re.compile(r"(?P<sign>[+-]*)"
r"(?P<hours>\d+):"
r"(?P<mins>\d+):"
r"(?P<secs>\d+\.?\d*)")
deg_re = re.compile(r"(?P<sign>[+-])*"
r"(?P<degs>\d+)\."
r"(?P<mins>\d+)\."
r"(?P<secs>\d+\.?\d*)")
def _hour_converter(hour_str):
m = hour_re.match(hour_str)
if not m:
raise ValueError("Error parsing '%s'" % hour_str)
value = float(m.group("hours")) / 24.0
value += float(m.group("mins")) / (24.0*60.0)
value += float(m.group("secs")) / (24.0*60.0*60.0)
if m.group("sign") == '-':
value = -value
return 2.0 * math.pi * value
def _deg_converter(deg_str):
m = deg_re.match(deg_str)
if not m:
raise ValueError("Error parsing '%s'" % deg_str)
value = float(m.group("degs")) / 360.0
value += float(m.group("mins")) / (360.0*60.0)
value += float(m.group("secs")) / (360.0*60.0*60.0)
if m.group("sign") == '-':
value = -value
return 2.0 * math.pi * value
def arcsec2rad(arcseconds=0.0):
return np.deg2rad(float(arcseconds) / 3600.)
_COLUMN_CONVERTERS = {
'Name': str,
'Type': str,
'Ra': _hour_converter,
'Dec': _deg_converter,
'I': float,
'SpectralIndex': literal_eval,
'LogarithmicSI': lambda x: bool(x == "true"),
'ReferenceFrequency': float,
'MajorAxis': arcsec2rad,
'MinorAxis': arcsec2rad,
'Orientation': lambda x=0.0: np.deg2rad(float(x)),
}
# Split on commas, ignoring within [] brackets
_COMMA_SPLIT_RE = re.compile(r',\s*(?=[^\]]*(?:\[|$))')
# Parse columm headers, handling possible defaults
_COL_HEADER_RE = re.compile(r"^\s*?(?P<name>.*?)"
r"(\s*?=\s*?'(?P<default>.*?)'\s*?){0,1}$")
def _parse_col_descriptor(column_descriptor):
components = [c.strip() for c in column_descriptor.split(",")]
columns = []
defaults = []
for column in components:
m = _COL_HEADER_RE.search(column)
if m is None:
raise ValueError("'%s' is not a valid column header" % column)
name, default = m.group('name', 'default')
columns.append(name)
defaults.append(default)
return columns, defaults
def _parse_header(header):
format_str, col_desc = (c.strip() for c in header.split("=", 1))
if format_str != "Format":
raise ValueError("'%s' does not appear to be a wsclean header")
return _parse_col_descriptor(col_desc)
def _parse_lines(fh, line_nr, column_names, defaults, converters):
source_data = [[] for _ in range(len(column_names))]
for line_nr, line in enumerate(fh, line_nr):
components = [c.strip() for c in re.split(_COMMA_SPLIT_RE, line)]
if len(components) != len(column_names):
raise ValueError("line %d '%s' should have %d components" %
(line_nr, line, len(column_names)))
# Iterate through each column's data
it = zip(column_names, components, converters, source_data, defaults)
for name, comp, conv, data_list, default in it:
if not comp:
if default is None:
try:
default = conv()
except Exception as e:
raise ValueError("No value supplied for column '%s' "
"on line %d and no default was "
"supplied either. Attempting to "
"generate a default produced the "
"following exception %s"
% (name, line_nr, str(e)))
value = default
else:
value = comp
data_list.append(conv(value))
return zip(*(column_names, source_data))
[docs]def load(filename):
"""
Loads wsclean component model.
.. code-block:: python
sources = load("components.txt")
sources = dict(sources) # Convert to dictionary
I = sources["I"]
ref_freq = sources["ReferenceFrequency"]
See the `WSClean Component List
<https://sourceforge.net/p/wsclean/wiki/ComponentList/>`_
for further details.
Parameters
----------
filename : str or iterable
Filename of wsclean model file or iterable
producing the lines of the file.
See Also
--------
africanus.model.wsclean.spectra
Returns
-------
list of (name, list of values) tuples
list of column (name, value) tuples
"""
if isinstance(filename, str):
fh = open(filename, "r")
fh = iter(fh)
close_filename = True
else:
fh = iter(filename)
close_filename = False
try:
# Search for a header until we find a non-empty string
header = ''
line_nr = 1
for headers in fh:
header = headers.split("#", 1)[0].strip()
if header:
break
line_nr += 1
if not header:
raise ValueError("'%s' does not contain a valid wsclean header"
% filename)
column_names, defaults = _parse_header(header)
try:
converters = [_COLUMN_CONVERTERS[n] for n in column_names]
except KeyError as e:
raise ValueError("No converter registered for column %s" % str(e))
return _parse_lines(fh, line_nr, column_names, defaults, converters)
finally:
if close_filename:
fh.close()