From d4936d32a8799eed715881babbcd38f9c611a748 Mon Sep 17 00:00:00 2001
From: Stefan Krastanov <stefan@krastanov.org>
Date: Sat, 2 Nov 2024 09:54:01 -0400
Subject: [PATCH] minor cleanup

---
 ext/QuantumCliffordGPUExt/apply_noise.jl |  2 +-
 src/QuantumClifford.jl                   |  8 ++------
 src/pauli_frames.jl                      | 24 ++++++++++++------------
 src/pauli_operator.jl                    |  2 +-
 4 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/ext/QuantumCliffordGPUExt/apply_noise.jl b/ext/QuantumCliffordGPUExt/apply_noise.jl
index 277ead68a..201eb7c60 100644
--- a/ext/QuantumCliffordGPUExt/apply_noise.jl
+++ b/ext/QuantumCliffordGPUExt/apply_noise.jl
@@ -3,8 +3,8 @@ using QuantumClifford: get_bitmask_idxs
 #according to https://github.com/JuliaGPU/CUDA.jl/blob/ac1bc29a118e7be56d9edb084a4dea4224c1d707/test/core/device/random.jl#L33
 #CUDA.jl supports calling rand() inside kernel
 function applynoise!(frame::PauliFrameGPU{T},noise::UnbiasedUncorrelatedNoise,i::Int) where {T <: Unsigned}
-    xzs = frame.frame.tab.xzs
     p = noise.p
+    xzs = tab(frame.frame).xzs
     lowbit, ibig, ismall, ismallm = get_bitmask_idxs(xzs,i)
     rows = size(stab, 1)
 
diff --git a/src/QuantumClifford.jl b/src/QuantumClifford.jl
index 8a3555107..6b4945b6b 100644
--- a/src/QuantumClifford.jl
+++ b/src/QuantumClifford.jl
@@ -26,7 +26,7 @@ export
     nqubits,
     stabilizerview, destabilizerview, logicalxview, logicalzview, phases,
     fastcolumn, fastrow,
-    bitview, quantumstate, tab, rank, get_bitmask_idxs,
+    bitview, quantumstate, tab, rank,
     BadDataStructure,
     affectedqubits, #TODO move to QuantumInterface?
     # GF2
@@ -926,12 +926,8 @@ the following values based on the index `i`:
 - `ibig`, the index of the word containing the bit.
 - `ismall`, the position of the bit within the word.
 - `ismallm`, a bitmask isolating the specified bit.
-
-Internal bitwise operations `_div`, `_mod`, and `_mask` are
-used to compute the word and bit positions based on the bit
-size of the type `T`.
 """
-function get_bitmask_idxs(xzs::AbstractArray{<:Unsigned}, i::Int)
+@inline function get_bitmask_idxs(xzs::AbstractArray{<:Unsigned}, i::Int)
     T = eltype(xzs)
     lowbit = T(1)
     ibig = _div(T, i-1) + 1
diff --git a/src/pauli_frames.jl b/src/pauli_frames.jl
index d5f037da5..af84bd63b 100644
--- a/src/pauli_frames.jl
+++ b/src/pauli_frames.jl
@@ -82,7 +82,7 @@ end
 function apply!(frame::PauliFrame, op::sMZ) # TODO sMY, and faster sMX
     op.bit == 0 && return frame
     i = op.qubit
-    xzs = frame.frame.tab.xzs
+    xzs = tab(frame.frame).xzs
     lowbit, ibig, ismall, ismallm = get_bitmask_idxs(xzs,i)
 
     @inbounds @simd for f in eachindex(frame)
@@ -95,7 +95,7 @@ end
 
 function apply!(frame::PauliFrame, op::sMRZ) # TODO sMRY, and faster sMRX
     i = op.qubit
-    xzs = frame.frame.tab.xzs
+    xzs = tab(frame.frame).xzs
     lowbit, ibig, ismall, ismallm = get_bitmask_idxs(xzs,i)
 
     if op.bit != 0
@@ -114,7 +114,7 @@ end
 
 function applynoise!(frame::PauliFrame,noise::UnbiasedUncorrelatedNoise,i::Int)
     p = noise.p
-    xzs = frame.frame.tab.xzs
+    xzs = tab(frame.frame).xzs
 
     lowbit, ibig, ismall, ismallm = get_bitmask_idxs(xzs,i)
     p = p/3
@@ -122,31 +122,31 @@ function applynoise!(frame::PauliFrame,noise::UnbiasedUncorrelatedNoise,i::Int)
     @inbounds @simd for f in eachindex(frame)
         r = rand()
         if  r < p # X error
-            frame.frame.tab.xzs[ibig,f] ⊻= ismallm
+            xzs[ibig,f] ⊻= ismallm
         elseif r < 2p # Z error
-            frame.frame.tab.xzs[end÷2+ibig,f] ⊻= ismallm
+            xzs[end÷2+ibig,f] ⊻= ismallm
         elseif r < 3p # Y error
-            frame.frame.tab.xzs[ibig,f] ⊻= ismallm
-            frame.frame.tab.xzs[end÷2+ibig,f] ⊻= ismallm
+            xzs[ibig,f] ⊻= ismallm
+            xzs[end÷2+ibig,f] ⊻= ismallm
         end
     end
     return frame
 end
 
 function applynoise!(frame::PauliFrame,noise::PauliNoise,i::Int)
-    xzs = frame.frame.tab.xzs
+    xzs = tab(frame.frame).xzs
 
     lowbit, ibig, ismall, ismallm = get_bitmask_idxs(xzs,i)
 
     @inbounds @simd for f in eachindex(frame)
         r = rand()
         if  r < noise.px # X error
-            frame.frame.tab.xzs[ibig,f] ⊻= ismallm
+            xzs[ibig,f] ⊻= ismallm
         elseif r < noise.px+noise.pz # Z error
-            frame.frame.tab.xzs[end÷2+ibig,f] ⊻= ismallm
+            xzs[end÷2+ibig,f] ⊻= ismallm
         elseif r < noise.px+noise.pz+noise.py # Y error
-            frame.frame.tab.xzs[ibig,f] ⊻= ismallm
-            frame.frame.tab.xzs[end÷2+ibig,f] ⊻= ismallm
+            xzs[ibig,f] ⊻= ismallm
+            xzs[end÷2+ibig,f] ⊻= ismallm
         end
     end
     return frame
diff --git a/src/pauli_operator.jl b/src/pauli_operator.jl
index ed0e89ec8..2246d4d5f 100644
--- a/src/pauli_operator.jl
+++ b/src/pauli_operator.jl
@@ -87,7 +87,7 @@ macro P_str(a)
     quote _P_str($a) end
 end
 
-Base.getindex(p::PauliOperator{Tₚ,Tᵥ}, i::Int) where {Tₚ, Tᵥₑ<:Unsigned, Tᵥ<:AbstractVector{Tᵥₑ}} = begin
+function Base.getindex(p::PauliOperator{Tₚ,Tᵥ}, i::Int) where {Tₚ, Tᵥₑ<:Unsigned, Tᵥ<:AbstractVector{Tᵥₑ}}
     _, ibig, _, ismallm = get_bitmask_idxs(p.xz,i)
     ((p.xz[ibig] & ismallm) != 0x0)::Bool, ((p.xz[end÷2+ibig] & ismallm) != 0x0)::Bool
 end