Struct diffgeom::tensors::Tensor
[−]
[src]
pub struct Tensor<T: CoordinateSystem, U: Variance> where T::Dimension: Pow<U::Rank>, Power<T::Dimension, U::Rank>: ArrayLength<f64> {
// some fields omitted
}Struct representing a tensor.
A tensor is anchored at a given point and has coordinates
represented in the system defined by the generic parameter
T. The variance of the tensor (meaning its rank and types
of its indices) is defined by V. This allows Rust
to decide at compile time whether two tensors are legal
to be added / multiplied / etc.
It is only OK to perform an operation on two tensors if they belong to the same coordinate system.
Methods
impl<T, V> Tensor<T, V> where T: CoordinateSystem, V: Variance, T::Dimension: Pow<V::Rank>, Power<T::Dimension, V::Rank>: ArrayLength<f64>
fn get_point(&self) -> &Point<T>
Returns the point at which the tensor is defined.
fn get_coord(i: &[usize]) -> usize
Converts a set of tensor indices passed as a slice into a single index for the internal array.
The length of the slice (the number of indices) has to be compatible with the rank of the tensor.
fn get_variance() -> Vec<IndexType>
Returns the variance of the tensor, that is, the list of the index types. A vector would return vec![Contravariant], a metric tensor: vec![Covariant, Covariant].
fn get_rank() -> usize
Returns the rank of the tensor
fn get_num_coords() -> usize
Returns the number of coordinates of the tensor (equal to [Dimension][Rank])
fn new(point: Point<T>) -> Tensor<T, V>
Creates a new, zero tensor at a given point
fn from_slice(point: Point<T>, slice: &[f64]) -> Tensor<T, V>
Creates a tensor at a given point with the coordinates defined by the slice.
The number of elements in the slice must be equal to the number of coordinates of the tensor.
One-dimensional slice represents an n-dimensional tensor in such a way, that the last index is the one that is changing the most often, i.e. the sequence is as follows: (0,0,...,0), (0,0,...,1), (0,0,...,2), ..., (0,0,...,1,0), (0,0,...,1,1), ... etc.
fn trace<Ul, Uh>(&self) -> Tensor<T, Contracted<V, Ul, Uh>> where Ul: Unsigned, Uh: Unsigned, V: Contract<Ul, Uh>, Contracted<V, Ul, Uh>::Rank: ArrayLength<usize>, T::Dimension: Pow<Contracted<V, Ul, Uh>::Rank>, Power<T::Dimension, Contracted<V, Ul, Uh>::Rank>: ArrayLength<f64>
Contracts two indices
The indices must be of opposite types. This is checked at compile time.
impl<T, U> Tensor<T, U> where T: CoordinateSystem, U: Variance, U::Rank: ArrayLength<usize>, T::Dimension: Pow<U::Rank>, Power<T::Dimension, U::Rank>: ArrayLength<f64>
fn iter_coords(&self) -> CoordIterator<U>
Returns an iterator over the coordinates of the tensor.
impl<T, Ul, Ur> Tensor<T, (Ul, Ur)> where T: CoordinateSystem, Ul: TensorIndex + OtherIndex, Ur: TensorIndex + OtherIndex, Add1<Ul::Rank>: Unsigned + Add<U1>, Add1<Ur::Rank>: Unsigned + Add<U1>, Add1<Ul::Output::Rank>: Unsigned + Add<U1>, Add1<Ur::Output::Rank>: Unsigned + Add<U1>, (Ul, Ur)::Rank: ArrayLength<usize>, T::Dimension: Pow<Add1<Ul::Rank>> + Pow<Add1<Ur::Rank>> + ArrayLength<usize>, T::Dimension: Pow<Add1<Ul::Output::Rank>>, T::Dimension: Pow<Add1<Ur::Output::Rank>>, Power<T::Dimension, Add1<Ul::Rank>>: ArrayLength<f64>, Power<T::Dimension, Add1<Ur::Rank>>: ArrayLength<f64>, Power<T::Dimension, Add1<Ul::Output::Rank>>: ArrayLength<f64>, Power<T::Dimension, Add1<Ur::Output::Rank>>: ArrayLength<f64>
fn unit(p: Point<T>) -> Tensor<T, (Ul, Ur)>
Returns a unit matrix (1 on the diagonal, 0 everywhere else)
fn transpose(&self) -> Tensor<T, (Ur, Ul)>
Transposes the matrix
fn inverse(&self) -> Option<Tensor<T, (Ul::Output, Ur::Output)>>
Function calculating the inverse of self using the LU ddecomposition.
The return value is an Option, since self may be non-invertible -
in such a case, None is returned