Extended packed designation functionality

CHANGES.rst

@@ -1,3 +1,17 @@
+0.6.0 (unreleased)
+==================
+
+New Features
+------------
+
+sbpy.names
+^^^^^^^^^^
+- Added functionality to `sbpy.Names.from_packed()` and
+  `sbpy.Names.to_packed()` to handle new extended provisional designations
+  to be implemented by the MPC in anticipation of higher asteroid discovery
+  rates in the LSST survey era [#406]
+
+
 0.5.0 (2024-08-28)
 ==================
 

docs/sbpy/data/names.rst

@@ -112,9 +112,13 @@ numbers and unpacked ones:
 
     >>> Names.from_packed('J95A01A')
     '1995 AA1'
+    >>> Names.from_packed('_RD0aEM')
+    '2027 DZ6190'
     >>> Names.from_packed('G3693')
     163693
     >>> Names.to_packed('1995 AA1')
     'J95A01A'
+    >>> Names.to_packed('2027 DZ6190')
+    '_RD0aEM'
     >>> Names.to_packed('163693')
     'G3693'

sbpy/data/names.py

@@ -11,6 +11,7 @@
 """
 
 import re
+import math
 from ..exceptions import SbpyException
 
 __all__ = ['Names', 'TargetNameParseError', 'natural_sort_key']
@@ -68,6 +69,9 @@
     pkd = ('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
            'abcdefghijklmnopqrstuvwxyz')
 
+    # packed numbers translation string with no I
+    pkd_noI = 'ABCDEFGHJKLMNOPQRSTUVWXYZ'
+
     @staticmethod
     def to_packed(s):
         """Convert designation or number to packed identifier.
@@ -94,14 +98,22 @@
             s = int(s)
             if s < 100000:
                 return '{:05d}'.format(s)
-            elif s > 619999:
-                raise TargetNameParseError(
-                    '{} cannot be turned into a packed number'.format(s)
-                )
-            else:
+            elif (s > 99999 and s < 620000):
                 mod = (s % 10000)
                 return '{}{:04d}'.format(
                     Names.pkd[int((s - mod) / 10000)], mod)
+            elif (s > 619999 and s < 15396336):
+                s = s - 620000
+                d = ['0', '0', '0', '0']
+                for idx in reversed(range(0, 4)):
+                    d[idx] = Names.pkd[math.floor(s % 62)]
+                    s //= 62
+                return ('~'+''.join(d))
+            else:
+                raise TargetNameParseError(
+                    '{} cannot be turned into a packed number'.format(s)
+                )
+
         elif s.endswith('P-L'):
             return 'PLS{}'.format(s[:4])
         elif s[-3:] in ['T-1', 'T-2', 'T-3']:
@@ -123,42 +135,61 @@
                     frag = '0'
                     num = s[6:]
 
-                if num == '':
-                    num = '00'
-                elif len(num) == 1:
-                    num = '0' + num
-                elif len(num) > 2:
-                    try:
+                try:
+                    if num == '':
+                        num = '00'
+                    elif len(num) == 1:
+                        num = '0' + num
+                    elif len(num) > 2:
                         num = Names.pkd[int(num[:-1])]+num[-1]
-                    except (IndexError, ValueError):
-                        raise TargetNameParseError(
-                            ('{} cannot be turned into a '
-                             'packed designation').format(s))
-                return '{}{}{}{}{}'.format(
-                    Names.pkd[int(float(s[:2]))],
-                    s[2:4],
-                    s[5],
-                    num,
-                    frag.lower()
-                )
+                    return '{}{}{}{}{}'.format(
+                        Names.pkd[int(float(s[:2]))],
+                        s[2:4],
+                        s[5],
+                        num,
+                        frag.lower()
+                    )
+                except (IndexError, ValueError):
+                    raise TargetNameParseError(
+                        ('{} cannot be turned into a '
+                         'packed designation').format(s))
             else:
-                yr = s.strip()[:4]
-                yr = Names.pkd[int(yr[:2])] + yr[2:]
-                let = s.strip()[4:7].strip()
-                num = s.strip()[7:].strip()
-                if num == '':
-                    num = '00'
-                elif len(num) == 1:
-                    num = '0' + num
-                elif len(num) > 2:
-                    try:
-                        num = Names.pkd[int(num[:-1])]+num[-1]
-                    except (IndexError, ValueError):
-                        raise TargetNameParseError(
-                            ('{} cannot be turned into a '
-                             'packed designation').format(s))
-            return (yr + let[0] + num + let[1])
-
+                try:
+                    yr = s.strip()[:4]
+                    yr = Names.pkd[int(yr[:2])] + yr[2:]
+                    let = s.strip()[4:7].strip()
+                    num = s.strip()[7:].strip()
+
+                    if num == '':
+                        return (yr + let[0] + '00' + let[1])
+                    elif len(num) == 1:
+                        return (yr + let[0] + '0' + num + let[1])
+                    elif len(num) > 1:
+                        obj_num = int(num)*25 + Names.pkd_noI.find(let[1]) + 1
+                        # use original packed desigs for first 15500 objs per month
+                        if obj_num < 15501:
+                            num = Names.pkd[int(num[:-1])]+num[-1]
+                            return (yr + let[0] + num + let[1])
+                        # use extended packed desigs for >15500 objs per month
+                        elif obj_num < 14791837:
+                            obj_num = obj_num - 15501
+                            year = Names.pkd[int(yr[1:])]
+                            month = let[0]
+                            d = ['0', '0', '0', '0']
+                            for idx in reversed(range(0, 4)):
+                                d[idx] = Names.pkd[math.floor(obj_num % 62)]
+                                obj_num //= 62
+                            return ('_'+Names.pkd[int(yr[1:])]+let[0]+''.join(d))
+                        # if more than maximum of 14,791,836 objects per half-month
+                        # accommodated by the extended provisional designation scheme
+                        else:
+                            raise TargetNameParseError(
+                                ('{} cannot be turned into a '
+                                 'packed number or designation').format(s))
+                except (IndexError, ValueError):
+                    raise TargetNameParseError(
+                        ('{} cannot be turned into a '
+                         'packed number or designation').format(s))
         else:
             raise TargetNameParseError(
                 ('{} cannot be turned into a '
@@ -189,6 +220,17 @@
             return int(p)
         elif p[0].isalpha() and p[1:].isdigit():
             return int(str(Names.pkd.find(p[0])) + p[1:])
+        elif p[0] == '~' and p[1:].isalnum():
+            if len(p) == 5:
+                obj_num = 620000 + Names.pkd.find(p[1])*(62**3) \
+                    + Names.pkd.find(p[2])*(62**2) \
+                    + Names.pkd.find(p[3])*(62) \
+                    + Names.pkd.find(p[4])
+                return int(obj_num)
+            else:
+                raise TargetNameParseError(
+                    ('{} cannot be turned into an '
+                     'unpacked designation').format(p))
 
         # old designation style, e.g.: 1989AB
         if (len(p.strip()) < 7 and p[:4].isdigit() and p[4:6].isalpha()):
@@ -216,6 +258,27 @@
                 (str(Names.pkd.find(p[4])) + p[5]).lstrip('0'),
                 '-{}'.format(p[6].upper()) if p[6].islower() else ''
             )
+        # MPC extended packed provisional designation
+        elif p[0] == '_':
+            if (
+                (p[1].isalpha() and p[1].isupper())
+                and re.search("[A-H,J-Y]", p[2])
+                and p[3:].isalnum()
+                and len(p) == 7
+            ):
+                obj_num = 15501 + Names.pkd.find(p[3])*(62**3) \
+                    + Names.pkd.find(p[4])*(62**2) \
+                    + Names.pkd.find(p[5])*(62) \
+                    + Names.pkd.find(p[6])
+                return '20{} {}{}{}'.format(
+                    str(Names.pkd.find(p[1])),
+                    p[2],
+                    Names.pkd_noI[((obj_num-1) % 25)],
+                    math.floor((obj_num-1)/25))
+            else:
+                raise TargetNameParseError(
+                    ('{} cannot be turned into an '
+                     'unpacked designation').format(p))
         else:
             # nothing to do
             return p

sbpy/data/tests/test_names.py

@@ -102,6 +102,12 @@ def test_from_packed():
 
     Test values from https://www.minorplanetcenter.net/iau/info/PackedDes.html
 
+    Test values for extended permanent designations from
+    https://www.minorplanetcenter.net/iau/info/PackedDes.html
+
+    Test values for extended provisional designations from
+    https://minorplanetcenter.net/mpcops/documentation/provisional-designation-definition/
+
     """
 
     # minor planets
@@ -129,6 +135,22 @@ def test_from_packed():
     assert Names.from_packed('K33L89c') == '2033 L89-C'
     assert Names.from_packed('K88AA30') == '2088 A103'
 
+    # extended permanent designations
+    assert Names.from_packed('~0000') == 620000
+    assert Names.from_packed('~000z') == 620061
+    assert Names.from_packed('~AZaz') == 3140113
+    assert Names.from_packed('~zzzz') == 15396335
+
+    # extended provisional designations
+    assert Names.from_packed('_QC0000') == '2026 CA620'
+    assert Names.from_packed('_QC0aEM') == '2026 CZ6190'
+    assert Names.from_packed('_QCzzzz') == '2026 CL591673'
+    assert Names.from_packed('_PD0000') == '2025 DA620'
+    assert Names.from_packed('_QD000N') == '2026 DY620'
+    assert Names.from_packed('_RD0aEM') == '2027 DZ6190'
+    assert Names.from_packed('_SEZZZZ') == '2028 EA339749'
+    assert Names.from_packed('_TFzzzz') == '2029 FL591673'
+
     # a few other tests
     assert Names.from_packed('50000') == 50000
     assert Names.from_packed('A0345') == 100345
@@ -142,6 +164,12 @@ def test_to_packed():
 
     Test values from https://www.minorplanetcenter.net/iau/info/PackedDes.html
 
+    Test values for extended permanent designations from
+    https://www.minorplanetcenter.net/iau/info/PackedDes.html
+
+    Test values for extended provisional designations from
+    https://minorplanetcenter.net/mpcops/documentation/provisional-designation-definition/
+
     """
 
     # minor planets
@@ -169,6 +197,22 @@ def test_to_packed():
     assert Names.to_packed('2033 L89-C') == 'K33L89c'
     assert Names.to_packed('2088 A103') == 'K88AA30'
 
+    # extended permanent designations
+    assert Names.to_packed('620000') == '~0000'
+    assert Names.to_packed('620061') == '~000z'
+    assert Names.to_packed('3140113') == '~AZaz'
+    assert Names.to_packed('15396335') == '~zzzz'
+
+    # extended provisional designations
+    assert Names.to_packed('2026 CA620') == '_QC0000'
+    assert Names.to_packed('2026 CZ6190') == '_QC0aEM'
+    assert Names.to_packed('2026 CL591673') == '_QCzzzz'
+    assert Names.to_packed('2025 DA620') == '_PD0000'
+    assert Names.to_packed('2026 DY620') == '_QD000N'
+    assert Names.to_packed('2027 DZ6190') == '_RD0aEM'
+    assert Names.to_packed('2028 EA339749') == '_SEZZZZ'
+    assert Names.to_packed('2029 FL591673') == '_TFzzzz'
+
     # a few other tests
     assert Names.to_packed('50000') == '50000'
     assert Names.to_packed('100345') == 'A0345'
@@ -223,11 +267,40 @@ def test_parse_asteroid():
 
 
 def test_break_packed():
-    with pytest.raises(TargetNameParseError):
-        Names.to_packed('620000')
-
     with pytest.raises(TargetNameParseError):
         Names.to_packed('2015 this will not work')
 
     with pytest.raises(TargetNameParseError):
         Names.to_packed('thiswillnotwork')
+
+
+def test_raises_error():
+    with pytest.raises(TargetNameParseError):
+        Names.to_packed('2011 AA123456789')
+
+    with pytest.raises(TargetNameParseError):
+        Names.to_packed('2011 A123456789')
+
+    with pytest.raises(TargetNameParseError):
+        Names.to_packed('2026 CL591674')
+
+    with pytest.raises(TargetNameParseError):
+        Names.to_packed('1989 A')
+
+    with pytest.raises(TargetNameParseError):
+        Names.to_packed('15396336')
+
+    with pytest.raises(TargetNameParseError):
+        Names.from_packed('~555555')
+
+    with pytest.raises(TargetNameParseError):
+        Names.from_packed('_QCzzzz0')
+
+    with pytest.raises(TargetNameParseError):
+        Names.from_packed('_Qczzzz')
+
+    with pytest.raises(TargetNameParseError):
+        Names.from_packed('_QCzz_z')
+
+    with pytest.raises(TargetNameParseError):
+        Names.from_packed('_qCzzzz')