mirror of https://github.com/rust-lang/rust
120 lines
3.4 KiB
Rust
120 lines
3.4 KiB
Rust
#![feature(generic_const_exprs)]
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#![allow(incomplete_features)]
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trait TensorDimension {
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const DIM: usize;
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//~^ ERROR cycle detected when resolving instance
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//~| ERROR cycle detected when resolving instance
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// FIXME Given the current state of the compiler its expected that we cycle here,
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// but the cycle is still wrong.
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const ISSCALAR: bool = Self::DIM == 0;
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fn is_scalar(&self) -> bool {
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Self::ISSCALAR
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}
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}
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trait TensorSize: TensorDimension {
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fn size(&self) -> [usize; Self::DIM];
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fn inbounds(&self, index: [usize; Self::DIM]) -> bool {
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index.iter().zip(self.size().iter()).all(|(i, s)| i < s)
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}
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}
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trait Broadcastable: TensorSize + Sized {
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type Element;
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fn bget(&self, index: [usize; Self::DIM]) -> Option<Self::Element>;
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fn lazy_updim<const NEWDIM: usize>(
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&self,
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size: [usize; NEWDIM],
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) -> LazyUpdim<Self, { Self::DIM }, NEWDIM> {
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assert!(
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NEWDIM >= Self::DIM,
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"Updimmed tensor cannot have fewer indices than the initial one."
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);
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LazyUpdim { size, reference: &self }
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}
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fn bmap<T, F: Fn(Self::Element) -> T>(&self, foo: F) -> BMap<T, Self, F, { Self::DIM }> {
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BMap { reference: self, closure: foo }
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}
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}
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struct LazyUpdim<'a, T: Broadcastable, const OLDDIM: usize, const DIM: usize> {
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size: [usize; DIM],
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reference: &'a T,
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}
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impl<'a, T: Broadcastable, const DIM: usize> TensorDimension for LazyUpdim<'a, T, { T::DIM }, DIM> {
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const DIM: usize = DIM;
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}
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impl<'a, T: Broadcastable, const DIM: usize> TensorSize for LazyUpdim<'a, T, { T::DIM }, DIM> {
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fn size(&self) -> [usize; DIM] {
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self.size
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}
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}
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impl<'a, T: Broadcastable, const DIM: usize> Broadcastable for LazyUpdim<'a, T, { T::DIM }, DIM> {
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type Element = T::Element;
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fn bget(&self, index: [usize; DIM]) -> Option<Self::Element> {
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assert!(DIM >= T::DIM);
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if !self.inbounds(index) {
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return None;
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}
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let size = self.size();
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let newindex: [usize; T::DIM] = Default::default();
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self.reference.bget(newindex)
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}
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}
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struct BMap<'a, R, T: Broadcastable, F: Fn(T::Element) -> R, const DIM: usize> {
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reference: &'a T,
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closure: F,
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}
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impl<'a, R, T: Broadcastable, F: Fn(T::Element) -> R, const DIM: usize> TensorDimension
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for BMap<'a, R, T, F, DIM>
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{
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const DIM: usize = DIM;
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}
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impl<'a, R, T: Broadcastable, F: Fn(T::Element) -> R, const DIM: usize> TensorSize
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for BMap<'a, R, T, F, DIM>
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{
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fn size(&self) -> [usize; DIM] {
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//~^ ERROR: method not compatible with trait
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self.reference.size()
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}
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}
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impl<'a, R, T: Broadcastable, F: Fn(T::Element) -> R, const DIM: usize> Broadcastable
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for BMap<'a, R, T, F, DIM>
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{
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type Element = R;
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fn bget(&self, index: [usize; DIM]) -> Option<Self::Element> {
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//~^ ERROR: method not compatible with trait
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self.reference.bget(index).map(&self.closure)
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}
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}
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impl<T> TensorDimension for Vec<T> {
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const DIM: usize = 1;
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}
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impl<T> TensorSize for Vec<T> {
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fn size(&self) -> [usize; 1] {
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[self.len()]
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}
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}
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impl<T: Clone> Broadcastable for Vec<T> {
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type Element = T;
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fn bget(&self, index: [usize; 1]) -> Option<T> {
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self.get(index[0]).cloned()
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}
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}
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fn main() {
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let v = vec![1, 2, 3];
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let bv = v.lazy_updim([3, 4]);
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let bbv = bv.bmap(|x| x * x);
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println!("The size of v is {:?}", bbv.bget([0, 2]).expect("Out of bounds."));
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}
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