TNT reciprocal space ASU: it's NOT wrt standard settings

unlike CCP4 ASU
epeisach · Apr 16, 2024 · 195f9ac · 195f9ac
1 parent e54c556
commit 195f9ac
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Showing 3 changed files with 18 additions and 10 deletions.
diff --git a/include/gemmi/symmetry.hpp b/include/gemmi/symmetry.hpp
@@ -2015,11 +2015,14 @@ struct ReciprocalAsu {
     if (sg == nullptr)
       fail("Missing space group");
     idx = spacegroup_tables::ccp4_hkl_asu[sg->number - 1];
-    if (tnt)
+    if (tnt) {
       idx += 10;
-    is_ref = sg->is_reference_setting();
-    if (!is_ref)
-      rot = sg->basisop().rot;
+      is_ref = true; // TNT ASU is given wrt current (not standard) settings
+    } else {
+      is_ref = sg->is_reference_setting();
+      if (!is_ref)
+        rot = sg->basisop().rot;
+    }
   }
 
   bool is_in(const Op::Miller& hkl) const {

diff --git a/prog/sg.cpp b/prog/sg.cpp
@@ -106,12 +106,14 @@ void print_info(const gemmi::SpaceGroup* sg, bool verbose) {
   printf("Is enantiomorphic: %s\n", sg->is_enantiomorphic() ? "yes" : "no");
   std::array<int, 3> gf = ops.find_grid_factors();
   printf("Grid restrictions: NX=%dn NY=%dn NZ=%dn\n", gf[0], gf[1], gf[2]);
-  for (bool tnt : {false, true})
-    printf("Reciprocal space ASU (%s)%s: %s%s\n",
-           tnt ? "TNT" : "CCP4",
-           is_reference ? "" : " wrt. standard setting",
-           tnt ? " " : "",
-           gemmi::ReciprocalAsu(sg, tnt).condition_str());
+  std::string wrt;
+  if (!is_reference)
+    wrt = " wrt. " + gemmi::get_spacegroup_reference_setting(sg->number).xhm();
+  printf("CCP4 reciprocal space ASU%s: %s\n",
+         wrt.c_str(),
+         gemmi::ReciprocalAsu(sg, false).condition_str());
+  printf("TNT reciprocal space ASU:  %s\n",
+         gemmi::ReciprocalAsu(sg, true).condition_str());
   gemmi::AsuBrick brick = gemmi::find_asu_brick(sg);
   printf("Direct space ASU brick: %s\n", brick.str().c_str());
   print_symmetry_operations(ops);

diff --git a/tests/test_symmetry.py b/tests/test_symmetry.py
@@ -347,6 +347,9 @@ def test_reciprocal_asu_checker(self):
         checker = gemmi.ReciprocalAsu(sg)
         self.assertTrue(checker.is_in([-5, 5, 1]))
         self.assertFalse(checker.is_in([5, 5, -1]))
+        checker = gemmi.ReciprocalAsu(sg, tnt=True)
+        self.assertTrue(checker.is_in([5, 5, -1]))
+        self.assertFalse(checker.is_in([-5, 5, 1]))
 
     def test_reflection_properties(self):
         sg = gemmi.SpaceGroup('I 1 2 1')