an assortment of small ecc cleanup tasks (#486)

* an assortment of small ecc cleanup tasks

* bump version number and changelog

* typo

Author: Krastanov

CHANGELOG.md

@@ -5,6 +5,11 @@
 
 # News
 
+## v0.9.18 - 2025-02-19
+
+- Fixes for rare crashes in the python BP decoders.
+- Less repetitive error messages.
+
 ## v0.9.17 - 2025-02-18
 
 - New memory structure and matrix inversion function for `random_destabilizer`, to reduce allocations and speed up repeated generation of many random destabilizers.

Project.toml

@@ -1,7 +1,7 @@
 name = "QuantumClifford"
 uuid = "0525e862-1e90-11e9-3e4d-1b39d7109de1"
 authors = ["Stefan Krastanov <[email protected]> and QuantumSavory community members"]
-version = "0.9.17"
+version = "0.9.18"
 
 [deps]
 Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"

ext/QuantumCliffordHeckeExt/QuantumCliffordHeckeExt.jl

@@ -3,7 +3,7 @@ module QuantumCliffordHeckeExt
 using DocStringExtensions
 
 import QuantumClifford, LinearAlgebra
-import Hecke: Group, GroupElem, AdditiveGroup, AdditiveGroupElem,
+import Hecke: Group, GroupElem, AdditiveGroupElem,
     GroupAlgebra, GroupAlgebraElem, FqFieldElem, representation_matrix, dim, base_ring,
     multiplication_table, coefficients, abelian_group, group_algebra, rand
 import Nemo

ext/QuantumCliffordPyQDecodersExt/QuantumCliffordPyQDecodersExt.jl

@@ -59,7 +59,7 @@ function PyBeliefPropOSDecoder(c; maxiter=nothing, bpmethod=nothing, errorrate=n
     error_rate = isnothing(errorrate) ? PythonCall.Py(0.0001) : errorrate
     isnothing(osdmethod) || osdmethod ∈ (:zeroorder, :exhaustive, :combinationsweep) || error(lazy"PyBeliefPropOSDecoder got an unknown OSD method argument. `osdmethod` must be one of :zeroorder, :exhaustive, :combinationsweep.")
     osd_method = get(Dict(:zeroorder => "OSD_0", :exhaustive => "OSD_E", :combinationsweep => "OSD_CS"), osdmethod, 0)
-    0≥osdorder || error(lazy"PyBeliefPropOSDecoder got an invalid OSD order argument. `osdorder` must be ≥0.")
+    osdorder≥0 || error(lazy"PyBeliefPropOSDecoder got an invalid OSD order argument. `osdorder` must be ≥0.")
     osd_order = osdorder
     pyx = ldpc.BpOsdDecoder(np.array(Hx); max_iter, bp_method, error_rate, osd_method, osd_order) # TODO should be sparse
     pyz = ldpc.BpOsdDecoder(np.array(Hz); max_iter, bp_method, error_rate, osd_method, osd_order) # TODO should be sparse
@@ -69,11 +69,13 @@ end
 parity_checks(d::PyBP) = d.H
 
 function decode(d::PyBP, syndrome_sample)
-    row_x = @view syndrome_sample[1:d.nx]
+    row_x = @view syndrome_sample[1:d.nx] # TODO figure out a lower-overhead way to move data to python (and make sure the ecc wiki still works after that change -- a lot of the cruft here is because of rare crashes when running the wiki evaluator)
     row_z = @view syndrome_sample[d.nx+1:end]
-    guess_z_errors = PythonCall.PyArray(d.pyx.decode(np.array(row_x)))
-    guess_x_errors = PythonCall.PyArray(d.pyz.decode(np.array(row_z)))
-    vcat(guess_x_errors, guess_z_errors)
+    PythonCall.GIL.@lock begin
+        guess_z_errors = PythonCall.PyArray(d.pyx.decode(PythonCall.Py(row_x).to_numpy()))
+        guess_x_errors = PythonCall.PyArray(d.pyz.decode(PythonCall.Py(row_z).to_numpy()))
+        vcat(guess_x_errors, guess_z_errors)
+    end
 end
 
 struct PyMatchingDecoder <: AbstractSyndromeDecoder # TODO all these decoders have the same fields, maybe we can factor out a common type
@@ -108,9 +110,11 @@ parity_checks(d::PyMatchingDecoder) = d.H
 function decode(d::PyMatchingDecoder, syndrome_sample)
     row_x = @view syndrome_sample[1:d.nx]
     row_z = @view syndrome_sample[d.nx+1:end]
-    guess_z_errors = PythonCall.PyArray(d.pyx.decode(row_x))
-    guess_x_errors = PythonCall.PyArray(d.pyz.decode(row_z))
-    vcat(guess_x_errors, guess_z_errors)
+    PythonCall.GIL.@lock begin
+        guess_z_errors = PythonCall.PyArray(d.pyx.decode(PythonCall.Py(row_x).to_numpy()))
+        guess_x_errors = PythonCall.PyArray(d.pyz.decode(PythonCall.Py(row_z).to_numpy()))
+        vcat(guess_x_errors, guess_z_errors)
+    end
 end
 
 function batchdecode(d::PyMatchingDecoder, syndrome_samples)

src/ecc/ECC.jl

@@ -314,7 +314,7 @@ function faults_matrix(c::Stabilizer)
     s, n = size(c)
     r = rank(md)
     k = n - r
-    k == n-s || @warn "`faults_matrix` was called on an ECC that has redundant rows (is rank-deficient). `faults_matrix` corrected for that, however this is a frequent source of mistakes and inefficiencies. We advise you remove redundant rows from your ECC."
+    k == n-s || @warn "`faults_matrix` was called on an ECC that has redundant rows (is rank-deficient). `faults_matrix` corrected for that, however this is a frequent source of mistakes and inefficiencies. We advise you remove redundant rows from your ECC." maxlog=1
     O = falses(2k, 2n)
     logviews = [logicalxview(md); logicalzview(md)]
     errors = [one(Stabilizer,n; basis=:X);one(Stabilizer,n)]