150 lines
5.5 KiB
Rust
150 lines
5.5 KiB
Rust
//! Abstract definition of a matrix data storage allocator.
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use std::any::Any;
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use crate::base::constraint::{SameNumberOfColumns, SameNumberOfRows, ShapeConstraint};
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use crate::base::dimension::{Dim, U1};
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use crate::base::{DefaultAllocator, Scalar};
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use crate::storage::{IsContiguous, RawStorageMut};
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use crate::StorageMut;
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use std::fmt::Debug;
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use std::mem::MaybeUninit;
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/// A matrix allocator of a memory buffer that may contain `R::to_usize() * C::to_usize()`
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/// elements of type `T`.
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///
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/// An allocator is said to be:
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/// − static: if `R` and `C` both implement `DimName`.
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/// − dynamic: if either one (or both) of `R` or `C` is equal to `Dyn`.
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///
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/// Every allocator must be both static and dynamic. Though not all implementations may share the
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/// same `Buffer` type.
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pub trait Allocator<T, R: Dim, C: Dim = U1>: Any + Sized {
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/// The type of buffer this allocator can instantiate.
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type Buffer: StorageMut<T, R, C> + IsContiguous + Clone + Debug;
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/// The type of buffer with uninitialized components this allocator can instantiate.
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type BufferUninit: RawStorageMut<MaybeUninit<T>, R, C> + IsContiguous;
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/// Allocates a buffer with the given number of rows and columns without initializing its content.
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fn allocate_uninit(nrows: R, ncols: C) -> Self::BufferUninit;
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/// Assumes a data buffer to be initialized.
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///
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/// # Safety
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/// The user must make sure that every single entry of the buffer has been initialized,
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/// or Undefined Behavior will immediately occur.
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unsafe fn assume_init(uninit: Self::BufferUninit) -> Self::Buffer;
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/// Allocates a buffer initialized with the content of the given iterator.
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fn allocate_from_iterator<I: IntoIterator<Item = T>>(
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nrows: R,
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ncols: C,
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iter: I,
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) -> Self::Buffer;
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#[inline]
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/// Allocates a buffer initialized with the content of the given row-major order iterator.
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fn allocate_from_row_iterator<I: IntoIterator<Item = T>>(
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nrows: R,
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ncols: C,
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iter: I,
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) -> Self::Buffer {
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let mut res = Self::allocate_uninit(nrows, ncols);
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let mut count = 0;
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unsafe {
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// OK because the allocated buffer is guaranteed to be contiguous.
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let res_ptr = res.as_mut_slice_unchecked();
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for (k, e) in iter
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.into_iter()
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.take(ncols.value() * nrows.value())
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.enumerate()
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{
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let i = k / ncols.value();
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let j = k % ncols.value();
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// result[(i, j)] = e;
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*res_ptr.get_unchecked_mut(i + j * nrows.value()) = MaybeUninit::new(e);
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count += 1;
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}
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assert!(
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count == nrows.value() * ncols.value(),
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"Matrix init. from row iterator: iterator not long enough."
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);
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<Self as Allocator<T, R, C>>::assume_init(res)
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}
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}
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}
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/// A matrix reallocator. Changes the size of the memory buffer that initially contains (`RFrom` ×
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/// `CFrom`) elements to a smaller or larger size (`RTo`, `CTo`).
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pub trait Reallocator<T: Scalar, RFrom: Dim, CFrom: Dim, RTo: Dim, CTo: Dim>:
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Allocator<T, RFrom, CFrom> + Allocator<T, RTo, CTo>
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{
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/// Reallocates a buffer of shape `(RTo, CTo)`, possibly reusing a previously allocated buffer
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/// `buf`. Data stored by `buf` are linearly copied to the output:
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///
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/// # Safety
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/// The following invariants must be respected by the implementors of this method:
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/// * The copy is performed as if both were just arrays (without taking into account the matrix structure).
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/// * If the underlying buffer is being shrunk, the removed elements must **not** be dropped
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/// by this method. Dropping them is the responsibility of the caller.
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unsafe fn reallocate_copy(
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nrows: RTo,
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ncols: CTo,
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buf: <Self as Allocator<T, RFrom, CFrom>>::Buffer,
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) -> <Self as Allocator<T, RTo, CTo>>::BufferUninit;
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}
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/// The number of rows of the result of a componentwise operation on two matrices.
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pub type SameShapeR<R1, R2> = <ShapeConstraint as SameNumberOfRows<R1, R2>>::Representative;
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/// The number of columns of the result of a componentwise operation on two matrices.
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pub type SameShapeC<C1, C2> = <ShapeConstraint as SameNumberOfColumns<C1, C2>>::Representative;
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// TODO: Bad name.
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/// Restricts the given number of rows and columns to be respectively the same.
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pub trait SameShapeAllocator<T, R1, C1, R2, C2>:
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Allocator<T, R1, C1> + Allocator<T, SameShapeR<R1, R2>, SameShapeC<C1, C2>>
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where
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R1: Dim,
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R2: Dim,
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C1: Dim,
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C2: Dim,
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ShapeConstraint: SameNumberOfRows<R1, R2> + SameNumberOfColumns<C1, C2>,
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{
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}
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impl<T, R1, R2, C1, C2> SameShapeAllocator<T, R1, C1, R2, C2> for DefaultAllocator
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where
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R1: Dim,
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R2: Dim,
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C1: Dim,
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C2: Dim,
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DefaultAllocator: Allocator<T, R1, C1> + Allocator<T, SameShapeR<R1, R2>, SameShapeC<C1, C2>>,
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ShapeConstraint: SameNumberOfRows<R1, R2> + SameNumberOfColumns<C1, C2>,
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{
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}
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// XXX: Bad name.
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/// Restricts the given number of rows to be equal.
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pub trait SameShapeVectorAllocator<T, R1, R2>:
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Allocator<T, R1> + Allocator<T, SameShapeR<R1, R2>> + SameShapeAllocator<T, R1, U1, R2, U1>
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where
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R1: Dim,
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R2: Dim,
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ShapeConstraint: SameNumberOfRows<R1, R2>,
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{
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}
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impl<T, R1, R2> SameShapeVectorAllocator<T, R1, R2> for DefaultAllocator
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where
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R1: Dim,
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R2: Dim,
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DefaultAllocator: Allocator<T, R1, U1> + Allocator<T, SameShapeR<R1, R2>>,
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ShapeConstraint: SameNumberOfRows<R1, R2>,
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{
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}
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