Crate tensor4all_quanticstransform 

Quantics transformation operators for tensor train methods.

This crate provides LinearOperator constructors for various transformations in Quantics representation. It is a Rust port of transformation functionality from Quantics.jl.

Overview

All transformations return LinearOperator from tensor4all-treetn for consistent operator application to tensor train states.

Available Transformations

• Flip: f(x) = g(2^R - x)
• Shift: f(x) = g(x + offset) mod 2^R
• Phase Rotation: f(x) = exp(iθx) * g(x)
• Cumulative Sum: y_i = Σ_{j<i} x_j
• Fourier Transform: Quantics Fourier Transform (QFT)
• Affine Transform: y = A*x + b with rational coefficients

Example

use tensor4all_quanticstransform::{flip_operator, BoundaryCondition};

// Create a flip operator for 8-bit quantics representation
let op = flip_operator(8, BoundaryCondition::Periodic).unwrap();
assert_eq!(op.mpo.node_count(), 8);

Structs

AffineParams

Affine transformation parameters.

FTCore

Convenience wrapper for forward/backward Fourier transform.

FourierOptions

Options for Fourier transform construction.

UnfusedTensorInfo

Information about the unfused tensor structure.

Enums

BoundaryCondition

Boundary condition for quantics transformations.

CarryDirection

Direction for carry propagation in binary arithmetic operations.

TriangleType

Type of triangular matrix for cumsum-like operators.

Functions

affine_operator

Create the operator that realizes the coordinate map y = A * x + b.

affine_transform_matrix

Compute the full affine transformation matrix directly (for verification).

affine_transform_tensors_unfused

Create unfused affine transformation tensors.

cumsum_operator

Create a cumulative sum operator: y_i = Σ_{j < i} x_j

flip_operator

Create a flip operator: f(x) = g(2^R - x)

flip_operator_multivar

Create a flip operator for one variable in a multi-variable system.

phase_rotation_operator

Create a phase rotation operator: f(x) = exp(iθx) * g(x)

phase_rotation_operator_multivar

Create a phase rotation operator for one variable in a multi-variable system.

quantics_fourier_operator

Create a Quantics Fourier Transform operator.

shift_operator

Create a shift operator: f(x) = g(x + offset) mod 2^R

shift_operator_multivar

Create a shift operator for one variable in a multi-variable system.

triangle_operator

Create a triangular matrix operator with the specified triangle type.