Broadcast cpu implementation.

This commit is contained in:
laurent
2023-06-23 16:16:52 +01:00
parent 83e75b3af8
commit 10a5807dff

View File

@ -13,6 +13,14 @@ pub enum CpuStorage {
F64(Vec<f64>),
}
fn unary_map<T, F: FnMut(usize) -> T>(shape: &Shape, stride: &[usize], f: F) -> Vec<T> {
if shape.is_contiguous(stride) {
(0..shape.elem_count()).map(f).collect()
} else {
StridedIndex::new(shape.dims(), stride).map(f).collect()
}
}
// This function maps over two strided index sequences. It supports broadcasting in case
// `lhs_stride` or `rhs_stride` has a length shorter than `shape`.
fn binary_map<T, F: FnMut((usize, usize)) -> T>(
@ -22,7 +30,10 @@ fn binary_map<T, F: FnMut((usize, usize)) -> T>(
mut f: F,
) -> Vec<T> {
let dims = shape.dims();
if dims.len() == lhs_stride.len() && dims.len() == rhs_stride.len() {
let broadcast_ldims = dims.len() - lhs_stride.len();
let broadcast_rdims = dims.len() - rhs_stride.len();
let elem_count = shape.elem_count();
if broadcast_ldims == 0 && broadcast_rdims == 0 {
if shape.is_contiguous(lhs_stride) && shape.is_contiguous(rhs_stride) {
(0..shape.elem_count()).map(|i| f((i, i))).collect()
} else {
@ -30,8 +41,34 @@ fn binary_map<T, F: FnMut((usize, usize)) -> T>(
let rhs_index = StridedIndex::new(dims, rhs_stride);
lhs_index.zip(rhs_index).map(f).collect()
}
} else if broadcast_rdims == 0 {
let mut res = Vec::new();
res.reserve(elem_count);
let lhs_index: Vec<_> = StridedIndex::new(dims, lhs_stride).collect();
let mut i = 0;
for rhs_i in StridedIndex::new(dims, rhs_stride) {
res.push(f((lhs_index[i], rhs_i)));
i += 1;
if i >= lhs_index.len() {
i = 0
}
}
res
} else if broadcast_ldims == 0 {
let mut res = Vec::new();
res.reserve(elem_count);
let rhs_index: Vec<_> = StridedIndex::new(dims, rhs_stride).collect();
let mut i = 0;
for lhs_i in StridedIndex::new(dims, lhs_stride) {
res.push(f((lhs_i, rhs_index[i])));
i += 1;
if i >= rhs_index.len() {
i = 0
}
}
res
} else {
todo!("implement broadcast")
panic!("unexpected broadcasting dims: {shape:?} {lhs_stride:?} {rhs_stride:?}")
}
}
@ -61,22 +98,19 @@ impl CpuStorage {
) -> Result<Self> {
match self {
Self::U32(storage) => {
let index = StridedIndex::new(shape.dims(), stride);
let mul = mul as u32;
let add = add as u32;
let data = index.map(|i| storage[i] * mul + add).collect();
let data = unary_map(shape, stride, |i| storage[i] * mul + add);
Ok(Self::U32(data))
}
Self::F32(storage) => {
let index = StridedIndex::new(shape.dims(), stride);
let mul = mul as f32;
let add = add as f32;
let data = index.map(|i| storage[i] * mul + add).collect();
let data = unary_map(shape, stride, |i| storage[i] * mul + add);
Ok(Self::F32(data))
}
Self::F64(storage) => {
let index = StridedIndex::new(shape.dims(), stride);
let data = index.map(|i| storage[i] * mul + add).collect();
let data = unary_map(shape, stride, |i| storage[i] * mul + add);
Ok(Self::F64(data))
}
}