Questions tagged [pymatching]
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49 questions
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In Google Stim, is there a separate algorithm for handling measurement errors that occur before the final round?
Based on the paper “Sparse Blossom: Correcting a Million Errors per Core Second with Minimum-Weight Matching,” my understanding is that the MWPM decoder performs minimum-weight matching between the ...
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How to Correct an Error in Stim Manually?
TLDR: I'm aware of how to generate a Stim circuit and sample detection events though am unable to more than 'observe' without using automated tools to decode which is not what I am looking to use. I'd ...
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Decoding 50-50 non deterministic observable with stim and PyMatching
From this answer, I understand that stim can not be used to simulate non-stabilizer circuit. However, one can still have non-deterministic observables with 50-50 probability. Suppose for example ...
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How to code heavy-hex in stim?
I am trying to test heavy-hex quantum error correction code and its decoding using mwpm (pymatching). However, I am not able to figure out how can I create a heavy-hex code in stim and deploy detector ...
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How to remove the defects from initial $|+\rangle_L$ preparation in stim?
Suppose I am preparing a logical $|+\rangle_L$ state in surface code. This requires resetting all qubits to $|+\rangle^{\otimes N}$ and then measure $Z$-stablizers. This process creates a bunch of $X$-...
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Get a correction ($e$) that satisfies $H.e=s$ from pymatching
I am running some experiments on the surface code where I need the correction that satisfies $H.e=s$ and not the prediction of whether the observable has flipped or not from pymatching. I am trying to ...
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The handling of radius in pymatching
In surface code, the weight connecting two nodes is determined using the Manhattan distance. However, in arXiv:2303.15933, the expansion of a region is illustrated using circles based on the radius ...
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Why does the error is always logical NOT when MWPM fails?
Consider the decoding of noisy syndrome using pymatching (as shown here) for the repetition code. The logical operator in this case is simply identity matrix. One could write the python code as
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MWPM decoding with PyMatching in presence of measurement error
I am trying to do decoding in presence of measurement error and bit-flip error for the repetition code. In the PyMatching version 0.2.2 https://pypi.org/project/PyMatching/0.2.3/ it mentions that
To ...
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Simulating error correction of multiple commuting logical operators with stim and pymatching
I'm trying to simulate error correction with the Floquet Color Code. On the torus, this code has two logical qubits. For efficiency, I'm want to simulate two commuting logical operators at the same ...
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`predictions` and `fault_ids` in Stim and PyMatching for surface code decoding
When I tried to use Stim and PyMatching to decode errors in a Rotated Planar code, I noticed that, Regardedless of the code distance, predictions.shape, as well as ...
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Parallelizing decode_to_edges_array (PyMatching)
I am trying to parallelise the function: matching.decode_to_edges_array() to somewhat batch decode, but I am consistently running into the same problem:
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user29731
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Sinter, decode_to_edges_array
Does anyone know if sinter has the capability of decoding to edges array? It's a method in the pymatching.
Thanks.
user29731
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What is the best way to parallelise processes across multiple cores when computing logical error rates with Stim and PyMatching?
I am currently trying to compute logical error rates for the surface code using Stim's detector error models and PyMatching for different distances and noise strengths.
tl;dr : What is the best ...
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How can I use surface code measurement data produced with Qiskit to run matching algorithms (e.g. PyMatching)?
I built a complex time-space dependent error model with Qiskit, and I am simulating surface codes with such error model to test their error correction capabilities. Qiskit supplies measurement data as ...
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What is OBSERVABLE_INCLUDE in Stim and what is usefulness Pymatching
I have a question about the role of OBSERVABLE_INCLUDE within Stim circuits and how Pymatching uses it in order to decode syndromes. As far as I have understood from the documentation, ...
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Pymatching: Will starting with arbitrary weights affect the MWPM decoding process?
I am trying to examine the effect of weights on the performance of MWPM decoder on 5-repetition code as a simple example from Pymatching2. The idea is to vary the input weights by changing the error ...
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How to compute Z logical operators of a toric code using Kunneth theorem?
I'm going through pymatching tutorial on constructing a toric code using hypergraph product of two repetition codes.
The hypergraph product code construction $H G P\left(H_1, H_2\right)$ takes as ...
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Finding the number of Failure for Surface Code by using Pymatching (without STIM): ValueError: The shape of the syndrome vector z is not valid
I run the surface code for distance-3 with 3 round. I am now trying to decode and find the number of failures. My error probability of 0.08.
Here are my syndrome results:
...
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Using Deterministic Errors in Stim Detector Circuit and decoding with Pymatching: X_ERROR(1) failing in PyMatching
the Question
Is there a standard way to use deterministic errors (so, for instance, X_ERROR(1)) in Stim with PyMatching? Currently, sometimes if I use ...
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How is the match graph extracted from a stim.circuit.detector_error_model?
Let's say we have an error mechanism error(0.1) D7 D8 ^ D9 D10 ^ D13 D15. I understand that Stim is trying to decompose the complex errors into graphlike errors. It ...
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Are there open source implementations of quantum error correction decoders?
To detect and correct for errors in a topological quantum memory (toric code for example) one needs a quantum error correction algorithm also known as decoder.
The minimum weight perfect matching (...
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Pymatching shows a large timing distribution to decode the same set of syndromes
I am interested in looking into histogram distributions of decoder timing for different syndrome inputs (sourced from stim) into pymatching. Unfortunately, it seems the histograms I product are more a ...
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Check_matrix in Pymatching and Understanding the Plot
In the simplest case, let's assume we have distance 2 surface code. The X stabilizers will be: X1X2X3 and X3X4X5 which is shown by the red lines.
So the parity check matrix will be:
$$
\begin{bmatrix}...
- 704
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Pymatching Toric Code vs Surface Code
I am looking the example of toric code in Pymatching.
Here is the code:
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