Fix symmetry issue

src/symmetry.cpp

@@ -189,33 +189,45 @@ point offsetToOrigin(const cell &c, const point &p)
 {
 	point d{};
 
-	while (p.m_x + d.m_x < (c.get_a() / 2))
+	while (p.m_x + d.m_x < -(c.get_a()))
 		d.m_x += c.get_a();
-	while (p.m_x + d.m_x > (c.get_a() / 2))
+	while (p.m_x + d.m_x > (c.get_a()))
 		d.m_x -= c.get_a();
 
-	while (p.m_y + d.m_y < (c.get_b() / 2))
+	while (p.m_y + d.m_y < -(c.get_b()))
 		d.m_y += c.get_b();
-	while (p.m_y + d.m_y > (c.get_b() / 2))
+	while (p.m_y + d.m_y > (c.get_b()))
 		d.m_y -= c.get_b();
 
-	while (p.m_z + d.m_z < (c.get_c() / 2))
+	while (p.m_z + d.m_z < -(c.get_c()))
 		d.m_z += c.get_c();
-	while (p.m_z + d.m_z > (c.get_c() / 2))
+	while (p.m_z + d.m_z > (c.get_c()))
 		d.m_z -= c.get_c();
 
 	return d;
 };
 
-std::tuple<int,int,int> offsetToOriginInt(const cell &c, const point &p)
+point offsetToOriginFractional(const point &p)
 {
-	auto o = offsetToOrigin(c, p);
-	return {
-		std::rintf(o.m_x / c.get_a()),
-		std::rintf(o.m_y / c.get_b()),
-		std::rintf(o.m_z / c.get_c())
-	};
-}
+	point d{};
+
+	while (p.m_x + d.m_x < -0.5f)
+		d.m_x += 1;
+	while (p.m_x + d.m_x > 0.5f)
+		d.m_x -= 1;
+
+	while (p.m_y + d.m_y < -0.5f)
+		d.m_y += 1;
+	while (p.m_y + d.m_y > 0.5f)
+		d.m_y -= 1;
+
+	while (p.m_z + d.m_z < -0.5f)
+		d.m_z += 1;
+	while (p.m_z + d.m_z > 0.5f)
+		d.m_z -= 1;
+
+	return d;
+};
 
 point spacegroup::operator()(const point &pt, const cell &c, sym_op symop) const
 {
@@ -228,17 +240,12 @@ point spacegroup::operator()(const point &pt, const cell &c, sym_op symop) const
 	t.m_translation.m_y += symop.m_tb - 5;
 	t.m_translation.m_z += symop.m_tc - 5;
 
-	auto t_orth = orthogonal(t, c);
+	auto fpt = fractional(pt, c);
+	auto o = offsetToOriginFractional(fpt);
 
-	auto o = offsetToOrigin(c, pt);
-	transformation tlo(identity_matrix<float>(3), o);
-	auto itlo = cif::inverse(tlo);
+	auto spt = t(fpt + o) - o;
 
-	point result = pt + o;
-	result = t_orth(result);
-	result = itlo(result);
-
-	return result;
+	return orthogonal(spt, c);
 }
 
 point spacegroup::inverse(const point &pt, const cell &c, sym_op symop) const
@@ -252,25 +259,16 @@ point spacegroup::inverse(const point &pt, const cell &c, sym_op symop) const
 	t.m_translation.m_y += symop.m_tb - 5;
 	t.m_translation.m_z += symop.m_tc - 5;
 
-	auto t_orth = cif::inverse(orthogonal(t, c));
+	auto it = cif::inverse(t);
 
-	auto o = offsetToOrigin(c, pt);
-	transformation tlo(identity_matrix<float>(3), o);
-	auto itlo = cif::inverse(tlo);
+	auto fpt = fractional(pt, c);
+	auto o = offsetToOriginFractional(fpt);
 
-	point result = pt + o;
-	result = t_orth(result);
-	result = itlo(result);
-
-	return result;
+	auto spt = it(fpt + o) - o;
+	return orthogonal(spt, c);
 }
 
 // --------------------------------------------------------------------
-// Unfortunately, clipper has a different numbering scheme than PDB
-// for rotation numbers. So we created a table to map those.
-// Perhaps a bit over the top, but hey....
-
-// --------------------------------------------------------------------
 
 int get_space_group_number(std::string_view spacegroup)
 {
@@ -399,18 +397,20 @@ std::tuple<float,point,sym_op> closest_symmetry_copy(const spacegroup &sg, const
 	if (c.get_a() == 0 or c.get_b() == 0 or c.get_c() == 0)
 		throw std::runtime_error("Invalid cell, contains a dimension that is zero");
 
-	point result_p;
+	point result_fsb;
 	float result_d = std::numeric_limits<float>::max();
 	sym_op result_s;
 
-	auto o = offsetToOrigin(c, a);
-
-	a += o;
-	b += o;
-
 	auto fa = fractional(a, c);
 	auto fb = fractional(b, c);
 
+	auto o = offsetToOriginFractional(fa);
+
+	fa = fa + o;
+	fb = fb + o;
+
+	a = orthogonal(fa, c);
+
 	for (size_t i = 0; i < sg.size(); ++i)
 	{
 		sym_op s(i + 1);
@@ -459,15 +459,14 @@ std::tuple<float,point,sym_op> closest_symmetry_copy(const spacegroup &sg, const
 		if (result_d > dsq)
 		{
 			result_d = dsq;
-			result_p = p;
+			result_fsb = fsb;
 			result_s = s;
 		}
 	}
 
-	transformation tlo(identity_matrix<float>(3), o);
-	auto itlo = cif::inverse(tlo);
+	auto p = orthogonal(result_fsb - o, c);
 
-	return { std::sqrt(result_d), itlo(result_p), result_s };
+	return { std::sqrt(result_d), p, result_s };
 }
 
 } // namespace cif

test/unit-3d-test.cpp

@@ -313,6 +313,38 @@ BOOST_AUTO_TEST_CASE(symm_4, *utf::tolerance(0.1f))
 	BOOST_TEST(distance(a, sb2) == 7.42f);	
 }
 
+// --------------------------------------------------------------------
+
+BOOST_AUTO_TEST_CASE(symm_4wvp_1, *utf::tolerance(0.1f))
+{
+	using namespace cif::literals;
+
+	cif::file f(gTestDir / "4wvp.cif.gz");
+
+	auto &db = f.front();
+	cif::mm::structure s(db);
+
+	cif::spacegroup sg(db);
+	cif::cell c(db);
+
+	cif::point p{ -78.722, 98.528,  11.994 };
+	auto a = s.get_residue("A", 10, "").get_atom_by_atom_id("O");
+
+	auto sp1 = cif::symmetry_copy(a.get_location(), sg, c, "2_565"_symop);
+	BOOST_TEST(sp1.m_x == p.m_x);
+	BOOST_TEST(sp1.m_y == p.m_y);
+	BOOST_TEST(sp1.m_z == p.m_z);
+
+	const auto &[d, sp2, so] = cif::closest_symmetry_copy(sg, c, p, a.get_location());
+
+	BOOST_TEST(d < 1);
+
+	BOOST_TEST(sp2.m_x == p.m_x);
+	BOOST_TEST(sp2.m_y == p.m_y);
+	BOOST_TEST(sp2.m_z == p.m_z);
+
+}
+
 BOOST_AUTO_TEST_CASE(symm_2bi3_1, *utf::tolerance(0.1f))
 {
 	cif::file f(gTestDir / "2bi3.cif.gz");
@@ -388,39 +420,6 @@ BOOST_AUTO_TEST_CASE(symm_3bwh_1, *utf::tolerance(0.1f))
 
 // --------------------------------------------------------------------
 
-
-BOOST_AUTO_TEST_CASE(symm_4wvp_1, *utf::tolerance(0.1f))
-{
-	using namespace cif::literals;
-
-	cif::file f(gTestDir / "4wvp.cif.gz");
-
-	auto &db = f.front();
-	cif::mm::structure s(db);
-
-	cif::spacegroup sg(db);
-	cif::cell c(db);
-
-	cif::point p{ -78.722, 98.528,  11.994 };
-	auto a = s.get_residue("A", 10, "").get_atom_by_atom_id("O");
-
-	auto sp1 = cif::symmetry_copy(a.get_location(), sg, c, "2_565"_symop);
-	BOOST_TEST(sp1.m_x == p.m_x);
-	BOOST_TEST(sp1.m_y == p.m_y);
-	BOOST_TEST(sp1.m_z == p.m_z);
-
-
-
-	const auto &[d, sp, so] = cif::closest_symmetry_copy(sg, c, p, a.get_location());
-
-	BOOST_TEST(d < 1);
-
-}
-
-
-
-// --------------------------------------------------------------------
-
 BOOST_AUTO_TEST_CASE(eigen_1, *utf::tolerance(0.1f))
 {
 	cif::symmetric_matrix4x4<float> m;