Struct EinsumExpr 

pub struct EinsumExpr { /* private fields */ }

Parsed einsum expression with N inputs (indices as ASCII codes)

Supports 1 to N input tensors. Output indices can be explicit (->out) or implicitly inferred (free indices sorted alphabetically).

Examples

use ariadnetor_core::EinsumExpr;

// Matrix multiplication
let expr = EinsumExpr::parse("ij,jk->ik").unwrap();
assert_eq!(expr.num_inputs(), 2);
assert!(expr.is_matrix_multiply());
assert_eq!(expr.infer_output_shape(&[&[10, 20], &[20, 30]]).unwrap(), vec![10, 30]);

// Higher-dimensional contraction (not a plain matmul)
let expr = EinsumExpr::parse("ijk,jkl->il").unwrap();
assert_eq!(expr.out_indices(), &[b'i', b'l']);
assert_eq!(expr.contracted_indices(), vec![b'j', b'k']);
assert!(!expr.is_matrix_multiply());

// Element-wise: every index appears in the output, nothing is contracted
let expr = EinsumExpr::parse("ij,ij->ij").unwrap();
assert!(expr.contracted_indices().is_empty());

// Implicit output inference
let expr = EinsumExpr::parse("ij,jk").unwrap();
assert_eq!(expr.out_indices(), &[b'i', b'k']);

// Single tensor trace
let expr = EinsumExpr::parse("ii->").unwrap();
assert_eq!(expr.num_inputs(), 1);

// Errors: an output index absent from every input, or a non-alphabetic index
assert!(EinsumExpr::parse("ij,jk->im").is_err());
assert!(EinsumExpr::parse("i1,jk->ik").is_err());

Implementations

impl EinsumExpr

pub fn parse(notation: &str) -> Result<EinsumExpr, String>

Parse an einsum expression from string notation.

When -> is present, output indices are explicit. When -> is omitted, output is inferred as free indices (appearing exactly once across all inputs) sorted alphabetically.

pub fn validate(&self) -> Result<(), String>

Validate the einsum expression.

Checks that all output indices appear in at least one input tensor.

pub fn inputs(&self) -> &[Vec<u8>]

Get all input index lists

pub fn out_indices(&self) -> &[u8]

Get output indices

pub fn num_inputs(&self) -> usize

Number of input tensors

pub fn lhs_indices(&self) -> &[u8]

Convenience accessor for the first input’s indices.

Panics

Panics if the expression has no inputs.

pub fn rhs_indices(&self) -> &[u8]

Convenience accessor for the second input’s indices.

Panics

Panics if the expression has fewer than 2 inputs.

pub fn all_indices(&self) -> HashSet<u8>

Get all unique indices across inputs and output

pub fn contracted_indices(&self) -> Vec<u8>

Get contracted indices (appear in inputs but not in output), preserving the order of first appearance across inputs.

Examples

let expr = EinsumExpr::parse("ijk,jkl->il").unwrap();
assert_eq!(expr.contracted_indices(), vec![b'j', b'k']);

pub fn is_matrix_multiply(&self) -> bool

Check if this is a matrix multiplication pattern: 2 inputs, 3 unique indices, each input has 2 indices, output has 2 indices, exactly 1 contracted index.

Examples

assert!(EinsumExpr::parse("ij,jk->ik").unwrap().is_matrix_multiply());
assert!(!EinsumExpr::parse("ijk,jkl->il").unwrap().is_matrix_multiply());

pub fn infer_output_shape( &self, shapes: &[&[usize]], ) -> Result<Vec<usize>, String>

Infer the output tensor shape from input shapes.

The number of shapes must match num_inputs(), and each shape’s rank must match its corresponding input index count. Shared indices must have matching dimensions.

Examples

let expr = EinsumExpr::parse("ij,jk->ik").unwrap();
assert_eq!(expr.infer_output_shape(&[&[10, 20], &[20, 30]]).unwrap(), vec![10, 30]);

Trait Implementations

impl Clone for EinsumExpr

fn clone(&self) -> EinsumExpr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EinsumExpr

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

Formats the value using the given formatter.

impl Eq for EinsumExpr

impl PartialEq for EinsumExpr

fn eq(&self, other: &EinsumExpr) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for EinsumExpr