Struct chemfiles::UnitCell

pub struct UnitCell { /* fields omitted */ }

An UnitCell represent the box containing the atoms, and its periodicity.

An unit cell is fully represented by three lengths (a, b, c); and three angles (alpha, beta, gamma). The angles are stored in degrees, and the lengths in Angstroms.

A cell also has a matricial representation, by projecting the three base vector into an orthonormal base. We choose to represent such matrix as an upper triangular matrix:

| a_x   b_x   c_x |
|  0    b_y   c_y |
|  0     0    c_z |

Implementations

impl UnitCell

pub fn new(lengths: [f64; 3]) -> UnitCell

Create an Orthorhombic UnitCell from the three lengths, in Angstroms.

Example

let cell = UnitCell::new([30.0, 30.0, 23.0]);

assert_eq!(cell.lengths(), [30.0, 30.0, 23.0]);
assert_eq!(cell.angles(), [90.0, 90.0, 90.0]);
assert_eq!(cell.shape(), CellShape::Orthorhombic);

pub fn infinite() -> UnitCell

Create an Infinite UnitCell.

Example

let cell = UnitCell::infinite();

assert_eq!(cell.lengths(), [0.0, 0.0, 0.0]);
assert_eq!(cell.angles(), [90.0, 90.0, 90.0]);
assert_eq!(cell.shape(), CellShape::Infinite);

pub fn triclinic(lengths: [f64; 3], angles: [f64; 3]) -> UnitCell

Create an Triclinic UnitCell from the three lengths (in Angstroms) and three angles (in degree). alpha is the angle between the vectors b and c; beta is the between the vectors a and c and gamma is the angle between the vectors a and b.

Example

let cell = UnitCell::triclinic([10.0, 10.0, 10.0], [98.0, 99.0, 90.0]);

assert_eq!(cell.lengths(), [10.0, 10.0, 10.0]);
assert_eq!(cell.angles()[0], 98.0);
// Rounding errors might occur due to internal representation
assert!((cell.angles()[1] - 99.0).abs() < 1e-12);
assert_eq!(cell.angles()[2], 90.0);
assert_eq!(cell.shape(), CellShape::Triclinic);

pub fn from_matrix(matrix: [[f64; 3]; 3]) -> UnitCell

Create an UnitCell from a cell matrix. If matrix contains only zeros, then an Infinite cell is created. If only the diagonal of the matrix is non-zero, then the cell is Orthorhombic. Else a Triclinic cell is created. The matrix entries should be in Angstroms.

Panics

If the matrix has a negative determinant, or more generally is not representing a unit cell.

Example

let cell = UnitCell::from_matrix([
    [1.0, 0.0, 0.0], [0.0, 2.0, 0.0], [0.0, 0.0, 3.0]
]);

assert_eq!(cell.lengths(), [1.0, 2.0, 3.0]);
assert_eq!(cell.angles(), [90.0, 90.0, 90.0]);
assert_eq!(cell.shape(), CellShape::Orthorhombic);

pub fn lengths(&self) -> [f64; 3]

Get the three lengths of the cell, in Angstroms.

Example

let cell = UnitCell::new([30.0, 30.0, 23.0]);
assert_eq!(cell.lengths(), [30.0, 30.0, 23.0]);

pub fn set_lengths(&mut self, lengths: [f64; 3]) -> Result<(), Error>

Set the three lengths of the cell, in Angstroms.

Errors

This function fails if the unit cell is infinite, or if one of the lengths is negative.

Example

let mut cell = UnitCell::new([30.0, 30.0, 23.0]);

cell.set_lengths([10.0, 30.0, 42.0]).unwrap();
assert_eq!(cell.lengths(), [10.0, 30.0, 42.0]);

assert!(UnitCell::infinite().set_lengths([1.0, 1.0, 1.0]).is_err());

pub fn angles(&self) -> [f64; 3]

Get the three angles of the cell, in degrees.

Example

let cell = UnitCell::new([20.0, 20.0, 20.0]);
assert_eq!(cell.angles(), [90.0, 90.0, 90.0]);

let cell = UnitCell::triclinic([20.0, 20.0, 20.0], [100.0, 120.0, 90.0]);
assert_eq!(cell.angles()[0], 100.0);
// Rounding errors might occur due to internal representation
assert!((cell.angles()[1] - 120.0).abs() < 1e-12);
assert_eq!(cell.angles()[2], 90.0);

pub fn set_angles(&mut self, angles: [f64; 3]) -> Result<(), Error>

Set the three angles of the cell, in degrees.

Errors

This function fails if the unit cell is not Triclinic.

Example

let mut cell = UnitCell::triclinic([20.0, 20.0, 20.0], [100.0, 120.0, 90.0]);
assert_eq!(cell.angles()[0], 100.0);
// Rounding errors might occur due to internal representation
assert!((cell.angles()[1] - 120.0).abs() < 1e-12);
assert_eq!(cell.angles()[2], 90.0);

cell.set_angles([90.0, 90.0, 90.0]).unwrap();
assert_eq!(cell.angles(), [90.0, 90.0, 90.0]);

pub fn matrix(&self) -> [[f64; 3]; 3]

Get the unit cell matricial representation.

The unit cell representation is obtained by aligning the a vector along the x axis and putting the b vector in the xy plane. This make the matrix an upper triangular matrix:

| a_x   b_x   c_x |
|  0    b_y   c_y |
|  0     0    c_z |

Example

let cell = UnitCell::new([10.0, 20.0, 30.0]);

let matrix = cell.matrix();

assert_eq!(matrix[0][0], 10.0);
assert_eq!(matrix[1][1], 20.0);
assert_eq!(matrix[2][2], 30.0);

assert!(matrix[1][2].abs() < 1e-9);

pub fn shape(&self) -> CellShape

Get the shape of the unit cell.

Example

let cell = UnitCell::new([10.0, 20.0, 30.0]);
assert_eq!(cell.shape(), CellShape::Orthorhombic);

pub fn set_shape(&mut self, shape: CellShape) -> Result<(), Error>

Set the shape of the unit cell to shape.

Errors

This can fail if the cell length or angles are incompatible with the new shape.

Example

let mut cell = UnitCell::new([10.0, 20.0, 30.0]);
assert_eq!(cell.shape(), CellShape::Orthorhombic);

cell.set_shape(CellShape::Triclinic).unwrap();
assert_eq!(cell.shape(), CellShape::Triclinic);

pub fn volume(&self) -> f64

Get the volume of the unit cell.

Example

let cell = UnitCell::new([10.0, 20.0, 30.0]);
assert_eq!(cell.volume(), 10.0 * 20.0 * 30.0);

pub fn wrap(&self, vector: &mut [f64; 3])

Wrap a vector in this unit cell.

Example

let cell = UnitCell::new([10.0, 20.0, 30.0]);

let mut vector = [12.0, 5.2, -45.3];
cell.wrap(&mut vector);
assert_eq!(vector, [2.0, 5.2, 14.700000000000003]);

Trait Implementations

impl Clone for UnitCell

fn clone(&self) -> UnitCell

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Drop for UnitCell

fn drop(&mut self)

Executes the destructor for this type.