possible way create a hash to get the data_prod_id

lmtoy/data_prod_id.py

@@ -0,0 +1,81 @@
+#! /usr/bin/env python3
+#
+
+"""Code to generate LMTOY data product reference ID."""
+
+import hashlib
+import itertools
+import base64
+
+def _make_unique_id(obsnums, is_sorted=False):
+    """Return a unique string for a list of obsnums."""
+    if not is_sorted:
+        obsnums = sorted(set(obsnums))
+    data = '_'.join(map(str, obsnums))
+    if True:
+        hash_object = hashlib.sha256(data.encode())
+        unique_id = base64.b32encode(hash_object.digest()).decode()
+    else:
+        hash_object = hashlib.sha256(data.encode())
+        unique_id = hash_object.hexdigest()
+
+    return unique_id
+
+def make_lmtoy_data_prod_id(obsnums, n=-1, hash_len=7):
+    """Return the reference ID for lmtoy data product
+       
+    Input:
+         obnums      a list of obsnums
+         n           used during testing, ignore now
+         hash_len    number of digits to use in the hash
+    """
+    # make
+    obsnums = sorted(set(obsnums))
+    n_obs = len(obsnums)
+    if n_obs == 0:
+        raise ValueError("list of obsnums cannot be empty.")
+    obsnum0 = obsnums[0]
+    obsnum1 = obsnums[n_obs-1]
+    if n_obs == 1:
+        #return f"o{obsnum0}s"     # toltec single
+        return f"{obsnum0}"  
+    uid = _make_unique_id(obsnums, is_sorted=True)
+    #return f"o{obsnum0}_c{n_obs}_{uid[:hash_len]}"        # toltec combo
+    #return f"{obsnum0}_{obsnum1}_{uid[:hash_len]}_{n}"
+    return f"{obsnum0}_{obsnum1}_{uid[:hash_len]}"
+
+if __name__ == '__main__':
+
+    obsnums = [
+        102284, 102295, 102297, 102333, 102336, 102365, 102369,
+        102373, 102381, 102384, 102386, 102411, 102413, 102486,
+        102489, 102511, 102516, 102580, 102586, 102599, 102604
+    ]
+    dpid = make_lmtoy_data_prod_id([obsnums[0]])
+    print(f"Data product ID: {dpid} (single)")    
+
+    dpid = make_lmtoy_data_prod_id(obsnums,0)
+    print(f"Data product ID: {dpid} (full combo)") 
+    test0 = dpid[:13]
+
+    print("Subsets:")
+    check_collision = []
+    n0 = 2
+    n1 = len(obsnums)
+    # n0 = n1-1          # zhiyuan
+    for n in range(n0,n1):
+        for ss in itertools.combinations(obsnums, n):
+            dpid = make_lmtoy_data_prod_id(ss,n)
+            if True:
+                if dpid[:13] != test0:
+                    continue
+            print(f"  Data product ID: {dpid}")
+            check_collision.append(dpid)
+
+    n1 = len(check_collision)
+    n2 = len(set(check_collision))
+    if n1 != n2:
+        print("Collisions found!",n1,n1-n2)
+    else:
+        print("No collision in ",n1)
+