Added cif::cell::get_volume()

changelog

 Version 5.2.3
 Version 5.2.3
 - New constructors for cif::item, one taking std::optional values
 - New constructors for cif::item, one taking std::optional values
   and another taking only a name resulting in a value '.' (i.e. inapplicable).
   and another taking only a name resulting in a value '.' (i.e. inapplicable).
+- added cif::cell::get_volume
 
 
 Version 5.2.2
 Version 5.2.2
 - Remove dependency on Eigen3 for users of libcifpp
 - Remove dependency on Eigen3 for users of libcifpp

include/cif++/symmetry.hpp

@@ -397,6 +397,8 @@ class cell
 	float get_beta() const { return m_beta; }   ///< return angle beta
 	float get_beta() const { return m_beta; }   ///< return angle beta
 	float get_gamma() const { return m_gamma; } ///< return angle gamma
 	float get_gamma() const { return m_gamma; } ///< return angle gamma
 
 
+	float get_volume() const; ///< return the calculated volume for this cell
+
 	matrix3x3<float> get_orthogonal_matrix() const { return m_orthogonal; } ///< return the matrix to use to transform coordinates from fractional to orthogonal
 	matrix3x3<float> get_orthogonal_matrix() const { return m_orthogonal; } ///< return the matrix to use to transform coordinates from fractional to orthogonal
 	matrix3x3<float> get_fractional_matrix() const { return m_fractional; } ///< return the matrix to use to transform coordinates from orthogonal to fractional
 	matrix3x3<float> get_fractional_matrix() const { return m_fractional; } ///< return the matrix to use to transform coordinates from orthogonal to fractional
 
 

src/symmetry.cpp

@@ -80,6 +80,22 @@ void cell::init()
 	m_fractional = inverse(m_orthogonal);
 	m_fractional = inverse(m_orthogonal);
 }
 }
 
 
+float cell::get_volume() const
+{
+	auto alpha = (m_alpha * kPI) / 180;
+	auto beta = (m_beta * kPI) / 180;
+	auto gamma = (m_gamma * kPI) / 180;
+
+	auto cos_alpha = std::cos(alpha);
+	auto cos_beta = std::cos(beta);
+	auto cos_gamma = std::cos(gamma);
+
+	auto vol = m_a * m_b * m_c;
+	vol *= std::sqrt(1.0f - cos_alpha * cos_alpha - cos_beta * cos_beta - cos_gamma * cos_gamma + 2.0f * cos_alpha * cos_beta * cos_gamma);
+
+	return vol;
+}
+
 // --------------------------------------------------------------------
 // --------------------------------------------------------------------
 
 
 sym_op::sym_op(std::string_view s)
 sym_op::sym_op(std::string_view s)

test/unit-3d-test.cpp

@@ -565,8 +565,6 @@ BOOST_AUTO_TEST_CASE(symm_2bi3_1a, *utf::tolerance(0.1f))
 	}
 	}
 }
 }
 
 
-
-
 BOOST_AUTO_TEST_CASE(symm_3bwh_1, *utf::tolerance(0.1f))
 BOOST_AUTO_TEST_CASE(symm_3bwh_1, *utf::tolerance(0.1f))
 {
 {
 	cif::file f(gTestDir / "3bwh.cif.gz");
 	cif::file f(gTestDir / "3bwh.cif.gz");
@@ -589,3 +587,15 @@ BOOST_AUTO_TEST_CASE(symm_3bwh_1, *utf::tolerance(0.1f))
 		}
 		}
 	}
 	}
 }
 }
+
+BOOST_AUTO_TEST_CASE(volume_3bwh_1, *utf::tolerance(0.1f))
+{
+	cif::file f(gTestDir / "1juh.cif.gz");
+
+	auto &db = f.front();
+
+	cif::crystal c(db);
+
+	BOOST_CHECK_EQUAL(c.get_cell().get_volume(), 741009.625f);
+}
+