use less boilerplace for get bitmasks in some other places as well

src/QuantumClifford.jl

@@ -922,7 +922,7 @@ Returns:
 - `ismallm`: A bitmask isolating the specified bit.
 
 """
-function get_bitmask_idxs(xzs::AbstractMatrix{UInt64}, i::Int)
+function get_bitmask_idxs(xzs::AbstractArray{<:Unsigned}, i::Int)
     T = eltype(xzs)
     lowbit = T(1)
     ibig = _div(T, i-1) + 1

src/pauli_operator.jl

@@ -87,19 +87,23 @@ 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}} = (p.xz[_div(Tᵥₑ, i-1)+1] & Tᵥₑ(0x1)<<_mod(Tᵥₑ,i-1))!=0x0, (p.xz[end÷2+_div(Tᵥₑ,i-1)+1] & Tᵥₑ(0x1)<<_mod(Tᵥₑ,i-1))!=0x0
+Base.getindex(p::PauliOperator{Tₚ,Tᵥ}, i::Int) where {Tₚ, Tᵥₑ<:Unsigned, Tᵥ<:AbstractVector{Tᵥₑ}} = begin
+    _, ibig, _, ismallm = get_bitmask_idxs(p.xz,i)
+    (p.xz[ibig] & ismallm) != 0x0, (p.xz[end÷2+ibig] & ismallm) != 0x0
+end
 Base.getindex(p::PauliOperator{Tₚ,Tᵥ}, r) where {Tₚ, Tᵥₑ<:Unsigned, Tᵥ<:AbstractVector{Tᵥₑ}} = PauliOperator(p.phase[], xbit(p)[r], zbit(p)[r])
 
 function Base.setindex!(p::PauliOperator{Tₚ,Tᵥ}, (x,z)::Tuple{Bool,Bool}, i) where {Tₚ, Tᵥₑ, Tᵥ<:AbstractVector{Tᵥₑ}}
+    _, ibig, _, ismallm = get_bitmask_idxs(p.xz,i)
     if x
-        p.xz[_div(Tᵥₑ,i-1)+1] |= Tᵥₑ(0x1)<<_mod(Tᵥₑ,i-1)
+        p.xz[ibig] |= ismallm
     else
-        p.xz[_div(Tᵥₑ,i-1)+1] &= ~(Tᵥₑ(0x1)<<_mod(Tᵥₑ,i-1))
+        p.xz[ibig] &= ~(ismallm)
     end
     if z
-        p.xz[end÷2+_div(Tᵥₑ,i-1)+1] |= Tᵥₑ(0x1)<<_mod(Tᵥₑ,i-1)
+        p.xz[end÷2+ibig] |= ismallm
     else
-        p.xz[end÷2+_div(Tᵥₑ,i-1)+1] &= ~(Tᵥₑ(0x1)<<_mod(Tᵥₑ,i-1))
+        p.xz[end÷2+ibig] &= ~(ismallm)
     end
     p
 end

src/project_trace_reset.jl

@@ -42,17 +42,15 @@ function _generate!(pauli::PauliOperator{Tₚ,Tᵥ}, stabilizer::Stabilizer{Tabl
     xzs = tab(stabilizer).xzs
     xs = @view xzs[1:end÷2,:]
     zs = @view xzs[end÷2+1:end,:]
-    lowbit = Tₘₑ(0x1)
     zerobit = Tₘₑ(0x0)
     px,pz = xview(pauli), zview(pauli)
     used_indices = Int[]
     used = 0
     # remove Xs
     while (i=unsafe_bitfindnext_(px,1); i !== nothing) # TODO awkward notation due to https://github.com/JuliaLang/julia/issues/45499
-        jbig = _div(Tₘₑ,i-1)+1
-        jsmall = lowbit<<_mod(Tₘₑ,i-1)
-        candidate = findfirst(e->e&jsmall!=zerobit, # TODO some form of reinterpret might be faster than equality check
-                              xs[jbig,used+1:end])
+        _, ibig, _, ismallm = get_bitmask_idxs(xzs,i)
+        candidate = findfirst(e->e&ismallm!=zerobit, # TODO some form of reinterpret might be faster than equality check
+                              xs[ibig,used+1:end])
         if isnothing(candidate)
             return nothing
         else
@@ -63,10 +61,9 @@ function _generate!(pauli::PauliOperator{Tₚ,Tᵥ}, stabilizer::Stabilizer{Tabl
     end
     # remove Zs
     while (i=unsafe_bitfindnext_(pz,1); i !== nothing) # TODO awkward notation due to https://github.com/JuliaLang/julia/issues/45499
-        jbig = _div(Tₘₑ,i-1)+1
-        jsmall = lowbit<<_mod(Tₘₑ,i-1)
-        candidate = findfirst(e->e&jsmall!=zerobit, # TODO some form of reinterpret might be faster than equality check
-                              zs[jbig,used+1:end])
+        _, ibig, _, ismallm = get_bitmask_idxs(xzs,i)
+        candidate = findfirst(e->e&ismallm!=zerobit, # TODO some form of reinterpret might be faster than equality check
+                              zs[ibig,used+1:end])
         if isnothing(candidate)
             return nothing
         else

src/symbolic_cliffords.jl

@@ -394,12 +394,9 @@ LinearAlgebra.inv(op::sInvZCrY) = sZCrY(op.q1, op.q2)
 """Apply a Pauli Z to the `i`-th qubit of state `s`. You should use `apply!(stab,sZ(i))` instead of this."""
 function apply_single_z!(stab::AbstractStabilizer, i)
     s = tab(stab)
-    Tₘₑ = eltype(s.xzs)
-    bigi = _div(Tₘₑ,i-1)+1
-    smalli = _mod(Tₘₑ,i-1)
-    mask = Tₘₑ(0x1)<<smalli
+    _, ibig, _, ismallm = get_bitmask_idxs(s.xzs,i)
     @inbounds @simd for row in 1:size(s.xzs,2)
-        if !iszero(s.xzs[bigi,row] & mask)
+        if !iszero(s.xzs[ibig,row] & ismallm)
             s.phases[row] = (s.phases[row]+0x2)&0x3
         end
     end
@@ -409,12 +406,9 @@ end
 """Apply a Pauli X to the `i`-th qubit of state `s`. You should use `apply!(stab,sX(i))` instead of this."""
 function apply_single_x!(stab::AbstractStabilizer, i)
     s = tab(stab)
-    Tₘₑ = eltype(s.xzs)
-    bigi = _div(Tₘₑ,i-1)+1
-    smalli = _mod(Tₘₑ,i-1)
-    mask = Tₘₑ(0x1)<<smalli
+    _, ibig, _, ismallm = get_bitmask_idxs(s.xzs,i)
     @inbounds @simd for row in 1:size(s.xzs,2)
-        if !iszero(s.xzs[end÷2+bigi,row] & mask)
+        if !iszero(s.xzs[end÷2+ibig,row] & ismallm)
             s.phases[row] = (s.phases[row]+0x2)&0x3
         end
     end
@@ -424,12 +418,9 @@ end
 """Apply a Pauli Y to the `i`-th qubit of state `s`. You should use `apply!(stab,sY(i))` instead of this."""
 function apply_single_y!(stab::AbstractStabilizer, i)
     s = tab(stab)
-    Tₘₑ = eltype(s.xzs)
-    bigi = _div(Tₘₑ,i-1)+1
-    smalli = _mod(Tₘₑ,i-1)
-    mask = Tₘₑ(0x1)<<smalli
+    _, ibig, _, ismallm = get_bitmask_idxs(s.xzs,i)
     @inbounds @simd for row in 1:size(s.xzs,2)
-        if !iszero((s.xzs[bigi,row] & mask) ⊻ (s.xzs[end÷2+bigi,row] & mask))
+        if !iszero((s.xzs[ibig,row] & ismallm) ⊻ (s.xzs[end÷2+ibig,row] & ismallm))
             s.phases[row] = (s.phases[row]+0x2)&0x3
         end
     end