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arxiv: 2311.10433 · v4 · submitted 2023-11-17 · 🪐 quant-ph · cs.ET

Task Scheduling Optimization with Direct Constraints from a Tensor Network Perspective

Pith reviewed 2026-05-24 05:59 UTC · model grok-4.3

classification 🪐 quant-ph cs.ET
keywords task scheduling optimizationtensor networksdirected constraintsquantum-inspiredcombinatorial optimizationindustrial applicationsexact algorithms
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The pith

A tensor network constructs an exact solution for optimal task scheduling with directed constraints by minimizing execution cost.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents a method to solve task scheduling optimization using tensor networks. It builds a network that captures all possible task-machine assignments respecting constraints and selects the one with lowest total cost. Techniques such as problem preprocessing, logical constraint condensation, and computation reuse lower the complexity. The main algorithm contracts the network, while the iterative version adds constraints as needed and the genetic version hybrids with evolutionary methods. Simple implementations were tested to show the approach works.

Core claim

By representing the scheduling problem as a tensor network that encodes the valid assignments and their costs, contracting the network after applying preprocessing, condensation, and reuse techniques provides an exact and explicit solution for the minimum-cost task combination under directed constraints.

What carries the argument

The tensor network representation of the problem tensor, which is contracted to find the optimal solution after reductions in complexity.

If this is right

  • Exact optimal schedules are computed rather than approximated.
  • Computational effort is reduced through preprocessing and intermediate result reuse.
  • The iterative algorithm incorporates only necessary constraints for efficiency.
  • Hybrid genetic search can accelerate finding solutions in some cases.
  • The methods are implemented and available for further testing.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Similar tensor network encodings might apply to other constraint satisfaction problems in operations research.
  • The quantum-inspired nature suggests potential for implementation on quantum hardware if tensor contractions can be mapped accordingly.
  • Scalability to very large industrial plants may require additional optimization beyond the described steps.
  • Benchmarking against classical solvers like integer programming would clarify practical advantages.

Load-bearing premise

After preprocessing and condensation, the tensor network remains small enough to contract in polynomial time for industrially relevant sizes.

What would settle it

If the method applied to a known small instance with a unique optimal schedule returns a non-optimal or invalid assignment, the claim of exactness would be falsified.

Figures

Figures reproduced from arXiv: 2311.10433 by Aitor Moreno Fdez. de Leceta, Alejandro Mata Ali, Beatriz Garc\'ia Markaida, I\~nigo Perez Delgado.

Figure 1
Figure 1. Figure 1: FIG. 1: Example of problem instance with [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2: Initialization nodes. a) Initial superposition [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3: Name of the indexes for the different tensors [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5: Tensor network performing the optimization, [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6: Scaling of the mean runtime of the normal algorithm with respect to different parameters. There are [PITH_FULL_IMAGE:figures/full_fig_p012_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7: Scaling of the mean runtime of the iterative algorithm with respect to different parameters. There are [PITH_FULL_IMAGE:figures/full_fig_p012_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8: Scaling of the mean number of required steps of the iterative algorithm with respect to different parameters. [PITH_FULL_IMAGE:figures/full_fig_p013_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: FIG. 9: Mean success rate of the genetic algorithm [PITH_FULL_IMAGE:figures/full_fig_p013_9.png] view at source ↗
read the original abstract

This work presents a novel method for task optimization in industrial plants using quantum-inspired tensor network technology. This method obtains the best possible combination of tasks on a set of machines with directed constraints while minimizing the total execution cost. With this method, an exact and explicit solution of the problem is provided. This algorithm constructs a tensor network representation of the tensor which provides the solution of the problem. This method is improved in order to reduce the computational complexity of the solution computation, using problem preprocessing, new techniques of condensation of logical constraints, optimization of the value determination technique with previously calculated results, reuse of intermediate computations, and iterative relations for constraints. Three algorithms for computation are presented: the main algorithm, the iterative algorithm which adds only the minimal amount of necessary constraints, and the genetic algorithm which combines the iterative algorithm with basic genetic algorithms. Finally, a simple version of both algorithms was implemented, and their performance was tested, all publicly available.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 3 minor

Summary. The paper presents a tensor network approach to task scheduling optimization with directed constraints, claiming to deliver an exact solution for the optimal task-machine assignment that minimizes total execution cost. The method constructs a tensor network representation of the problem, then applies preprocessing, condensation of logical constraints, reuse of intermediate results, and iterative relations to reduce complexity. Three algorithms are described (main, iterative adding minimal constraints, and a genetic variant), with a simplified implementation and performance tests on small instances made publicly available.

Significance. If the exactness claim holds under the described reductions, the work offers a quantum-inspired exact method for a practical constrained optimization problem, with the public code and empirical checks on small cases providing a verifiable starting point. The explicit algorithms and acknowledgment of general TN hardness are strengths that distinguish it from purely heuristic approaches.

minor comments (3)
  1. The abstract states that the tensor network 'provides the solution of the problem' but does not name the specific tensor indices or contraction order; a brief illustrative example in §3 or §4 would clarify how the optimal assignment is recovered from the contracted tensor.
  2. The iterative algorithm is described as adding 'only the minimal amount of necessary constraints,' yet no pseudocode or precise stopping criterion is supplied; adding this would improve reproducibility.
  3. Performance figures are reported only for small instances; a short discussion of observed scaling with number of tasks/machines (even if preliminary) would help readers assess the practical reach of the condensation steps.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive assessment of our work, the recognition of its strengths in providing explicit algorithms and acknowledging TN hardness, and the recommendation for minor revision. No major comments were provided in the report, so we have no specific points requiring response or revision at this stage.

Circularity Check

0 steps flagged

No significant circularity; derivation is self-contained

full rationale

The paper constructs a tensor-network representation of the scheduling problem, applies explicit preprocessing/condensation steps, and supplies three algorithms (main, iterative, genetic) whose correctness is verified on small instances with public code. No equations reduce a claimed result to a fitted parameter or self-citation by construction; the exactness claim rests on the explicit TN contraction after the listed reductions, which are independently described and not tautological. No load-bearing uniqueness theorem or ansatz is imported from prior self-work. The derivation chain therefore remains non-circular.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review supplies no explicit free parameters, axioms, or invented entities; ledger left empty pending full text.

pith-pipeline@v0.9.0 · 5706 in / 931 out tokens · 25337 ms · 2026-05-24T05:59:45.411905+00:00 · methodology

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Reference graph

Works this paper leans on

67 extracted references · 67 canonical work pages · 4 internal anchors

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    The creation of the initial uniform superposition state in the qudits:|ψ0⟩ = P ⃗ x|⃗ x⟩

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    The application of an imaginary time evolution, so that the amplitude of a combination depends on its cost and the damping constant τ: |ψ1⟩ =P ⃗ xe−τ C(⃗ x) |⃗ x⟩

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    Rnr−1e−τ C(⃗ x) |⃗ x⟩

    The removal of states by applying con- straints by means of projectors: |ψ2⟩ =P ⃗ xR0R1 . . . Rnr−1e−τ C(⃗ x) |⃗ x⟩

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    From a classical point of view, it consists of the follow- ing:

    The measurement and extraction of the basis state with the maximum amplitude of the superposition. From a classical point of view, it consists of the follow- ing:

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    The creation of the initial represented tensor where all elements are equal, representing all possible combinations: ψ0 x0,x1,... = 1

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    = e−τ C(⃗ x)

    The application of an operation to assign to ev- ery possible combination element a value propor- tional to its cost, with a damping constant τ: ψ1 x0,x1,... = e−τ C(⃗ x)

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    = R0 x0,x1,...R1 x0,x1,

    The removal of elements of incompatible com- binations by means of projective operations: ψ2 x0,x1,... = R0 x0,x1,...R1 x0,x1,... . . . Rnr−1 x0,x1,...e−τ C(⃗ x)

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    The measurement and extraction of the maximum element position of the represented tensor. This section is structured as follows. First, Ssec. IIIA presents the initialization and evolution tensor layers. Second, Ssec. IIIB presents the creation of the layers of tensors that implement the constraints, and Ssec. IIIC presents the application of the contrain...

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    This is because obviously these constraints will never be activated

    All the constraints in which the previous machine conditioned another machine and had to have a dif- ferent value than the one found are removed. This is because obviously these constraints will never be activated

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