Struct ErasedScanPlan 

pub struct ErasedScanPlan { /* private fields */ }

Dtype-erased cumulative scan (cumsum / cumprod) along one axis.

The destination has the source dimensions; source and destination strides are independent, and negative strides and offsets are accepted. Supported dtypes are f32, f64, i32, i64, c32 and c64; bool is rejected.

Evaluation order

Every output is the sequential left fold of its inputs in scan order (from the start of the axis, or from its end for a reverse scan), with no reassociation. The result is therefore bitwise identical for every layout, execution context and thread count. Integer scans wrap on overflow.

An empty axis or an empty set of lines writes nothing.

Examples

use strided_basic::{
    ErasedRawStridedMut, ErasedRawStridedRef, ErasedScanPlan, ExecContext, KernelDType,
    ScanOp, ScanOptions,
};

// A column-major 3 x 2 matrix, scanned along axis 0.
let src = [1.0_f64, 2.0, 3.0, 10.0, 20.0, 30.0];
let mut out = [0.0_f64; 6];
let plan = ErasedScanPlan::compile(
    KernelDType::F64,
    ScanOp::Sum,
    &[3, 2],
    &[1, 3],
    &[1, 3],
    0,
    ScanOptions::new(),
)
.unwrap();
let src_ref = ErasedRawStridedRef::from_slice(&src, &[3, 2], &[1, 3], 0).unwrap();
let mut dest = ErasedRawStridedMut::from_slice_mut(&mut out, &[3, 2], &[1, 3], 0).unwrap();
plan.execute(&ExecContext::serial(), &mut dest, &src_ref).unwrap();
assert_eq!(out, [1.0, 3.0, 6.0, 10.0, 30.0, 60.0]);

Implementations

impl ErasedScanPlan

pub fn compile( dtype: KernelDType, op: ScanOp, dims: &[usize], src_strides: &[isize], dest_strides: &[isize], axis: usize, options: ScanOptions, ) -> Result<Self>

Validate and store a scan plan for one dtype and fixed layouts.

dims are the shared source and destination dimensions; axis is the scanned axis.

Examples

use strided_basic::{ErasedScanPlan, KernelDType, ScanOp, ScanOptions};
let plan = ErasedScanPlan::compile(
    KernelDType::I64, ScanOp::Product, &[4], &[1], &[-1], 0, ScanOptions::new(),
)
.unwrap();
assert_eq!(plan.op(), ScanOp::Product);
assert!(ErasedScanPlan::compile(
    KernelDType::Bool, ScanOp::Sum, &[4], &[1], &[1], 0, ScanOptions::new(),
)
.is_err());

Errors

Returns UnsupportedDType for bool, InvalidAxis for an axis out of range, StrideLengthMismatch for inconsistent ranks, NonInjectiveOutputLayout for an aliasing destination layout, and OffsetOverflow when a layout’s offsets are not representable.

pub fn dtype(&self) -> KernelDType

Element dtype of the source and destination.

Examples

use strided_basic::{ErasedScanPlan, KernelDType, ScanOp, ScanOptions};
let plan = ErasedScanPlan::compile(
    KernelDType::F32, ScanOp::Sum, &[2], &[1], &[1], 0, ScanOptions::new(),
)
.unwrap();
assert_eq!(plan.dtype(), KernelDType::F32);

pub fn op(&self) -> ScanOp

Scan operation.

Examples

use strided_basic::{ErasedScanPlan, KernelDType, ScanOp, ScanOptions};
let plan = ErasedScanPlan::compile(
    KernelDType::F32, ScanOp::Sum, &[2], &[1], &[1], 0, ScanOptions::new(),
)
.unwrap();
assert_eq!(plan.op(), ScanOp::Sum);

pub fn options(&self) -> ScanOptions

Direction and inclusivity.

Examples

use strided_basic::{ErasedScanPlan, KernelDType, ScanOp, ScanOptions};
let options = ScanOptions::new().reverse(true);
let plan =
    ErasedScanPlan::compile(KernelDType::F32, ScanOp::Sum, &[2], &[1], &[1], 0, options)
        .unwrap();
assert_eq!(plan.options(), options);

pub fn execute( &self, ctx: &ExecContext, dest: &mut ErasedRawStridedMut<'_>, src: &ErasedRawStridedRef<'_>, ) -> Result<()>

Execute the scan into an initialized destination.

Examples

use strided_basic::{
    ErasedRawStridedMut, ErasedRawStridedRef, ErasedScanPlan, ExecContext, KernelDType,
    ScanOp, ScanOptions,
};
let src = [1_i32, 2, 3, 4];
let mut out = [0_i32; 4];
let options = ScanOptions::new().exclusive(true).reverse(true);
let plan =
    ErasedScanPlan::compile(KernelDType::I32, ScanOp::Sum, &[4], &[1], &[1], 0, options)
        .unwrap();
let src_ref = ErasedRawStridedRef::from_slice(&src, &[4], &[1], 0).unwrap();
let mut dest = ErasedRawStridedMut::from_slice_mut(&mut out, &[4], &[1], 0).unwrap();
plan.execute(&ExecContext::serial(), &mut dest, &src_ref).unwrap();
assert_eq!(out, [9, 7, 4, 0]);

Errors

Returns DTypeMismatch or PlanLayoutMismatch when a descriptor does not match the plan, before any destination write.

pub fn execute_uninit( &self, ctx: &ExecContext, dest: &mut ErasedRawStridedUninitMut<'_>, src: &ErasedRawStridedPtr<'_>, ) -> Result<()>

Execute the scan into an uninitialized destination.

On success every reachable destination element is written; validation errors are returned before any write.

Examples

use core::mem::MaybeUninit;
use strided_basic::{
    ErasedRawStridedPtr, ErasedRawStridedRef, ErasedRawStridedUninitMut, ErasedScanPlan,
    ExecContext, KernelDType, ScanOp, ScanOptions,
};
let src = [2.0_f32, 3.0, 4.0];
let mut out = [MaybeUninit::<f32>::uninit(); 3];
let plan = ErasedScanPlan::compile(
    KernelDType::F32, ScanOp::Product, &[3], &[1], &[1], 0, ScanOptions::new(),
)
.unwrap();
let src_ref = ErasedRawStridedRef::from_slice(&src, &[3], &[1], 0).unwrap();
let src_ptr = ErasedRawStridedPtr::from_ref(&src_ref);
let mut dest =
    ErasedRawStridedUninitMut::from_uninit_slice(&mut out, &[3], &[1], 0).unwrap();
plan.execute_uninit(&ExecContext::serial(), &mut dest, &src_ptr).unwrap();
let out: Vec<f32> = out.iter().map(|v| unsafe { v.assume_init() }).collect();
assert_eq!(out, [2.0, 6.0, 24.0]);

Errors

As Self::execute, plus OverlappingInputOutput when the source overlaps the destination allocation.

Trait Implementations

impl Clone for ErasedScanPlan

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ErasedScanPlan

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.