1 files changed, 133 insertions, 0 deletions
diff --git a/bin/cosmo_calc.py b/bin/cosmo_calc.py
new file mode 100755
index 0000000..1302bdb
--- /dev/null
+++ b/bin/cosmo_calc.py
@@ -0,0 +1,133 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2017 Weitian LI <liweitianux@live.com>
+# MIT license
+
+"""
+Cosmology calculator with support of Chandra ACIS-specific quantities.
+"""
+
+import sys
+import argparse
+from collections import OrderedDict
+
+from _context import acispy
+from acispy.cosmo import Calculator
+
+
+# Supported quantities
+QUANTITIES = OrderedDict([
+    ("luminosity_distance", {
+        "unit": "Mpc",
+        "label": "Luminosity distance",
+        "kwargs": ["z", "unit"],
+    }),
+    ("angular_diameter_distance", {
+        "unit": "Mpc",
+        "label": "Angular diameter distance",
+        "kwargs": ["z", "unit"],
+    }),
+    ("kpc_per_arcsec", {
+        "unit": None,
+        "label": "kpc/arcsec (DA)",
+        "kwargs": ["z"],
+    }),
+    ("kpc_per_pix", {
+        "unit": None,
+        "label": "kpc/pix (DA)",
+        "kwargs": ["z"],
+    }),
+    ("cm_per_pix", {
+        "unit": None,
+        "label": "cm/pix (DA)",
+        "kwargs": ["z"],
+    }),
+    ("norm_apec", {
+        "unit": "cm^-5",
+        "label": "norm (APEC)",
+        "kwargs": ["z"],
+    }),
+])
+
+
+def get_quantities(args):
+    # convert ``argparse.Namespace`` to a dictionary
+    args = vars(args)
+    q_all = list(QUANTITIES.keys())
+    q_active = [q for q in q_all if args[q]]
+    if len(q_active) == 0:
+        q_active = q_all
+    return q_active
+
+
+def calc_quantity(q, calculator, args):
+    args = vars(args)
+    kwargs = {arg: args[arg] for arg in QUANTITIES[q]["kwargs"]
+              if args[arg] is not None}
+    value = getattr(calculator, q)(**kwargs)
+    label = QUANTITIES[q]["label"]
+    unit = args["unit"] if args["unit"] is not None else QUANTITIES[q]["unit"]
+    if args["brief"]:
+        print(value)
+    else:
+        print("%s: %s  # [%s]" % (label, value, unit))
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Cosmology calculator with Chandra-specific quantities")
+    parser.add_argument("-H", "--hubble", dest="H0",
+                        type=float, default=71.0,
+                        help="Present-day Hubble parameter " +
+                        "(default: 71 km/s/Mpc)")
+    parser.add_argument("-M", "--omega-m", dest="Om0",
+                        type=float, default=0.27,
+                        help="Present-day matter density (default: 0.27")
+    parser.add_argument("-b", "--brief", dest="brief", action="store_true",
+                        help="be brief")
+    parser.add_argument("-U", "--unit", dest="unit",
+                        help="unit for output quantity if supported")
+    parser.add_argument("-L", "--luminosity-distance",
+                        dest="luminosity_distance",
+                        action="store_true",
+                        help="calculate the luminosity distance (DL)")
+    parser.add_argument("-A", "--angular-diameter-distance",
+                        dest="angular_diameter_distance",
+                        action="store_true",
+                        help="calculate the angular diameter distance (DA)")
+    parser.add_argument("--kpc-per-arcsec", dest="kpc_per_arcsec",
+                        action="store_true",
+                        help="calculate the transversal length [kpc] " +
+                        "w.r.t. 1 arcsec at DA(z)")
+    parser.add_argument("--kpc-per-pix", dest="kpc_per_pix",
+                        action="store_true",
+                        help="calculate the transversal length [kpc] " +
+                        "w.r.t. 1 ACIS pixel (0.492 arcsec) at DA(z)")
+    parser.add_argument("--cm-per-pix", dest="cm_per_pix",
+                        action="store_true",
+                        help="calculate the transversal length [cm] " +
+                        "w.r.t. 1 ACIS pixel (0.492 arcsec) at DA(z)")
+    parser.add_argument("--norm-apec", dest="norm_apec",
+                        action="store_true",
+                        help="calculate the normalization factor " +
+                        "of the XSPEC APEC model assuming EM=1")
+    parser.add_argument("z", type=float, help="redshift")
+    args = parser.parse_args()
+
+    cosmocalc = Calculator(H0=args.H0, Om0=args.Om0)
+
+    q_active = get_quantities(args)
+    if len(q_active) > 1:
+        if args.unit is not None:
+            args.unit = None
+            print("WARNING: ignored argument --unit", file=sys.stderr)
+        if args.brief:
+            args.brief = False
+            print("WARNING: ignored argument --brief", file=sys.stderr)
+
+    for q in q_active:
+        calc_quantity(q=q, calculator=cosmocalc, args=args)
+
+
+if __name__ == "__main__":
+    main()