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Non-allocating project! thanks to Val{Bool} in mul_left! (#41)
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Fixes #39
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@Krastanov
Krastanov authored Mar 23, 2022
1 parent f12a38f commit e8f94e9
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38 changes: 37 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -114,7 +114,7 @@ BenchmarkTools.Trial: 564 samples with 1 evaluation.
Memory estimate: 13.84 KiB, allocs estimate: 111.
```

#### Sparse gate application to only specified qubits in a 1000 qubit tableau in 4 microseconds
#### Sparse gate application to only specified qubits in a 1000 qubit tableau in 4 μs

```jldoctest
julia> @benchmark apply!(s, sCNOT(32,504)) setup=(s=random_stabilizer(1000))
Expand All @@ -130,4 +130,40 @@ BenchmarkTools.Trial: 10000 samples with 9 evaluations.
Memory estimate: 96 bytes, allocs estimate: 2.
```

#### Measuring a dense 1000 qubit Pauli operator in 74 μs

```jldoctest
julia> s=random_destabilizer(1000); p=random_pauli(1000);
julia> @benchmark project!(_s,_p) setup=(_s=copy(s);_p=copy(p)) evals=1
BenchmarkTools.Trial: 10000 samples with 1 evaluation.
Range (min … max): 69.030 μs … 144.963 μs ┊ GC (min … max): 0.00% … 0.00%
Time (median): 73.799 μs ┊ GC (median): 0.00%
Time (mean ± σ): 73.639 μs ± 4.118 μs ┊ GC (mean ± σ): 0.00% ± 0.00%
▂ ▁█▁
▃██▆▄▃▃▃▄▆▅▄▃▃███▃▂▂▂▁▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▁▂▂▂▂▂▂▂▂▂▂▂▂▂ ▃
69 μs Histogram: frequency by time 92.8 μs <
Memory estimate: 480 bytes, allocs estimate: 4.
```

#### Measuring a single qubit in a 1000 qubit tableau in 50 μs

```jldoctest
julia> s=MixedDestabilizer(random_destabilizer(1000));
julia> @benchmark projectY!(_s,42) setup=(_s=copy(s)) evals=1
BenchmarkTools.Trial: 10000 samples with 1 evaluation.
Range (min … max): 46.928 μs … 88.046 μs ┊ GC (min … max): 0.00% … 0.00%
Time (median): 49.934 μs ┊ GC (median): 0.00%
Time (mean ± σ): 49.776 μs ± 2.623 μs ┊ GC (mean ± σ): 0.00% ± 0.00%
▁ ▄█▂
▂▂▆██▄▄▄▄▆███▅▃▂▂▂▂▂▂▂▂▂▂▂▂▂▁▁▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▁▂▂▂▂▁▂ ▃
46.9 μs Histogram: frequency by time 63.8 μs <
Memory estimate: 464 bytes, allocs estimate: 5.
```

Benchmarks executed on a Ryzen Zen1 8-core CPU.
63 changes: 33 additions & 30 deletions src/QuantumClifford.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -743,8 +743,8 @@ function _mul_left_nonvec!(r::AbstractVector{T}, l::AbstractVector{T}; phases::B
s
end

function mul_left!(r::AbstractVector{T}, l::AbstractVector{T}; phases::Bool=true)::UInt8 where T<:Unsigned
if !phases
function mul_left!(r::AbstractVector{T}, l::AbstractVector{T}; phases::Val{B}=Val(true))::UInt8 where {T<:Unsigned, B}
if !B
r .⊻= l
return UInt8(0x0)
end
Expand Down Expand Up @@ -789,16 +789,16 @@ function mul_left!(r::AbstractVector{T}, l::AbstractVector{T}; phases::Bool=true
UInt8((rcnt1 ⊻ (rcnt2<<1))&0x3)
end

@inline function mul_left!(r::PauliOperator, l::PauliOperator; phases::Bool=true)
@inline function mul_left!(r::PauliOperator, l::PauliOperator; phases::Val{B}=Val(true)) where B
nqubits(l)==nqubits(r) || throw(DimensionMismatch("The two Pauli operators should have the same length!")) # TODO skip this when @inbounds is set
s = mul_left!(r.xz, l.xz, phases=phases)
phases && (r.phase[] = (s+r.phase[]+l.phase[])&0x3)
B && (r.phase[] = (s+r.phase[]+l.phase[])&0x3)
r
end

@inline function mul_left!(r::PauliOperator, l::Stabilizer, i::Int; phases::Bool=true)
@inline function mul_left!(r::PauliOperator, l::Stabilizer, i::Int; phases::Val{B}=Val(true)) where B
s = mul_left!(r.xz, (@view l.xzs[:,i]), phases=phases)
phases && (r.phase[] = (s+r.phase[]+l.phases[i])&0x3)
B && (r.phase[] = (s+r.phase[]+l.phases[i])&0x3)
r
end

Expand Down Expand Up @@ -861,24 +861,24 @@ end
rowswap!(s.tab, i+n, j+n; phases=phases)
end

@inline function mul_left!(s::Stabilizer, m, i; phases::Bool=true)
@inline function mul_left!(s::Stabilizer, m, i; phases::Val{B}=Val(true)) where B
extra_phase = mul_left!((@view s.xzs[:,m]), (@view s.xzs[:,i]); phases=phases)
phases && (s.phases[m] = (extra_phase+s.phases[m]+s.phases[i])&0x3)
B && (s.phases[m] = (extra_phase+s.phases[m]+s.phases[i])&0x3)
s
end

@inline function mul_left!(s::Destabilizer, i, j; phases::Bool=true)
mul_left!(s.tab, j, i; phases=false) # Indices are flipped to preserve commutation constraints
@inline function mul_left!(s::Destabilizer, i, j; phases::Val{B}=Val(true)) where B
mul_left!(s.tab, j, i; phases=Val(false)) # Indices are flipped to preserve commutation constraints
n = size(s.tab,1)÷2
mul_left!(s.tab, i+n, j+n; phases=phases)
end

@inline function mul_left!(s::MixedStabilizer, i, j; phases::Bool=true)
@inline function mul_left!(s::MixedStabilizer, i, j; phases::Val{B}=Val(true)) where B
mul_left!(s.tab, i, j; phases=phases)
end

@inline function mul_left!(s::MixedDestabilizer, i, j; phases::Bool=true)
mul_left!(s.tab, j, i; phases=false) # Indices are flipped to preserve commutation constraints
@inline function mul_left!(s::MixedDestabilizer, i, j; phases::Val{B}=Val(true)) where B
mul_left!(s.tab, j, i; phases=Val(false)) # Indices are flipped to preserve commutation constraints
n = nqubits(s)
mul_left!(s.tab, i+n, j+n; phases=phases)
end
Expand Down Expand Up @@ -1028,6 +1028,7 @@ Based on [garcia2012efficient](@cite).
See also: [`canonicalize_rref!`](@ref), [`canonicalize_gott!`](@ref)
"""
function canonicalize!(state::AbstractStabilizer; phases::Bool=true, ranks::Bool=false)
_phases = Val(phases)
xzs = stabilizerview(state).xzs
xs = @view xzs[1:end÷2,:]
zs = @view xzs[end÷2+1:end,:]
Expand All @@ -1047,7 +1048,7 @@ function canonicalize!(state::AbstractStabilizer; phases::Bool=true, ranks::Bool
rowswap!(state, k, i; phases=phases)
for m in 1:rows
if xs[jbig,m]&jsmall!=zerobit && m!=i # if X or Y
mul_left!(state, m, i; phases=phases)
mul_left!(state, m, i; phases=_phases)
end
end
i += 1
Expand All @@ -1065,7 +1066,7 @@ function canonicalize!(state::AbstractStabilizer; phases::Bool=true, ranks::Bool
rowswap!(state, k, i; phases=phases)
for m in 1:rows
if zs[jbig,m]&jsmall!=zerobit && m!=i # if Z or Y
mul_left!(state, m, i; phases=phases)
mul_left!(state, m, i; phases=_phases)
end
end
i += 1
Expand Down Expand Up @@ -1094,6 +1095,7 @@ Based on [audenaert2005entanglement](@cite).
See also: [`canonicalize!`](@ref), [`canonicalize_gott!`](@ref)
"""
function canonicalize_rref!(state::AbstractStabilizer, colindices; phases::Bool=true)
_phases = Val(phases)
xzs = stabilizerview(state).xzs
xs = @view xzs[1:end÷2,:]
zs = @view xzs[end÷2+1:end,:]
Expand All @@ -1111,7 +1113,7 @@ function canonicalize_rref!(state::AbstractStabilizer, colindices; phases::Bool=
rowswap!(state, k, i; phases=phases)
for m in 1:rows
if xs[jbig,m]&jsmall!=zerobit && m!=i # if X or Y
mul_left!(state, m, i; phases=phases)
mul_left!(state, m, i; phases=_phases)
end
end
i -= 1
Expand All @@ -1122,7 +1124,7 @@ function canonicalize_rref!(state::AbstractStabilizer, colindices; phases::Bool=
rowswap!(state, k, i; phases=phases)
for m in 1:rows
if zs[jbig,m]&jsmall!=zerobit && m!=i # if Z or Y
mul_left!(state, m, i; phases=phases)
mul_left!(state, m, i; phases=_phases)
end
end
i -= 1
Expand Down Expand Up @@ -1178,6 +1180,7 @@ Based on [gottesman1997stabilizer](@cite).
See also: [`canonicalize!`](@ref), [`canonicalize_rref!`](@ref)
"""
function canonicalize_gott!(stabilizer::Stabilizer{Tzv,Tm}; phases::Bool=true) where {Tzv<:AbstractVector{UInt8}, Tme<:Unsigned, Tm<:AbstractMatrix{Tme}}
_phases = Val(phases)
xzs = stabilizer.xzs
xs = @view xzs[1:end÷2,:]
zs = @view xzs[end÷2+1:end,:]
Expand All @@ -1196,7 +1199,7 @@ function canonicalize_gott!(stabilizer::Stabilizer{Tzv,Tm}; phases::Bool=true) w
rowswap!(stabilizer, k, i; phases=phases)
for m in 1:rows
if xs[jbig,m]&jsmall!=zerobit && m!=i # if X or Y
mul_left!(stabilizer, m, i; phases=phases)
mul_left!(stabilizer, m, i; phases=_phases)
end
end
i += 1
Expand All @@ -1216,7 +1219,7 @@ function canonicalize_gott!(stabilizer::Stabilizer{Tzv,Tm}; phases::Bool=true) w
rowswap!(stabilizer, k, i; phases=phases)
for m in 1:rows
if zs[jbig,m]&jsmall!=zerobit && m!=i # if Z or Y
mul_left!(stabilizer, m, i; phases=phases)
mul_left!(stabilizer, m, i; phases=_phases)
end
end
i += 1
Expand Down Expand Up @@ -1427,7 +1430,7 @@ function _apply_nonthread!(stab::AbstractStabilizer, c::CliffordOperator; phases
new_stabrow = zero(s_tab[1])
for row_stab in eachindex(s_tab)
zero!(new_stabrow)
apply_row_kernel!(new_stabrow, row_stab, s_tab, c_tab, phases=phases)
apply_row_kernel!(new_stabrow, row_stab, s_tab, c_tab, phases=Val(phases))
end
stab
end
Expand All @@ -1439,19 +1442,19 @@ function _apply!(stab::AbstractStabilizer, c::CliffordOperator; phases::Val{B}=V
c_tab = tab(c)
@batch minbatch=25 threadlocal=zero(c_tab[1]) for row_stab in eachindex(s_tab)
zero!(threadlocal) # a new stabrow for temporary storage
apply_row_kernel!(threadlocal, row_stab, s_tab, c_tab, phases=B)
apply_row_kernel!(threadlocal, row_stab, s_tab, c_tab, phases=phases)
end
stab
end

# TODO Added a lot of type assertions to help Julia infer types, but they are much too strict for cases where bitpacking varies (check tests)
#@inline function apply_row_kernel!(new_stabrow::PauliOperator{Array{UInt8,0},Vector{Tme}}, row::Int, s_tab::Stabilizer{Tv,Tm}, c_tab::Stabilizer{Tv,Tm}; phases=true) where {Tme,Tv<:AbstractVector{UInt8},Tm<:AbstractMatrix{Tme}}
@inline function apply_row_kernel!(new_stabrow, row, s_tab, c_tab; phases=true)
phases && (new_stabrow.phase[] = s_tab.phases[row])
@inline function apply_row_kernel!(new_stabrow, row, s_tab, c_tab; phases::Val{B}=Val(true)) where B
B && (new_stabrow.phase[] = s_tab.phases[row])
n = nqubits(c_tab)
for qubit in 1:n
x,z = s_tab[row,qubit]
if phases&&x&&z
if B&&x&&z
new_stabrow.phase[] -= 0x1
end
if x
Expand All @@ -1472,7 +1475,7 @@ function _apply_nonthread!(stab::AbstractStabilizer, c::CliffordOperator, indice
new_stabrow = zero(PauliOperator,nqubits(c))
for row in eachindex(s_tab)
zero!(new_stabrow)
apply_row_kernel!(new_stabrow, row, s_tab, c_tab, indices_of_application; phases=phases)
apply_row_kernel!(new_stabrow, row, s_tab, c_tab, indices_of_application; phases=Val(phases))
end
stab
end
Expand All @@ -1484,17 +1487,17 @@ function _apply!(stab::AbstractStabilizer, c::CliffordOperator, indices_of_appli
c_tab = tab(c)
@batch minbatch=25 threadlocal=zero(c_tab[1]) for row_stab in eachindex(s_tab)
zero!(threadlocal) # a new stabrow for temporary storage
apply_row_kernel!(threadlocal, row_stab, s_tab, c_tab, indices_of_application, phases=B)
apply_row_kernel!(threadlocal, row_stab, s_tab, c_tab, indices_of_application, phases=phases)
end
stab
end

@inline function apply_row_kernel!(new_stabrow, row, s_tab, c_tab, indices_of_application; phases=true)
phases && (new_stabrow.phase[] = s_tab.phases[row])
@inline function apply_row_kernel!(new_stabrow, row, s_tab, c_tab, indices_of_application; phases::Val{B}=Val(true)) where B
B && (new_stabrow.phase[] = s_tab.phases[row])
n = nqubits(c_tab)
for (qubit_i, qubit) in enumerate(indices_of_application)
x,z = s_tab[row,qubit]
if phases&&x&&z
if B&&x&&z
new_stabrow.phase[] -= 0x1
end
if x
Expand All @@ -1507,7 +1510,7 @@ end
for (qubit_i, qubit) in enumerate(indices_of_application)
s_tab[row,qubit] = new_stabrow[qubit_i]
end
phases && (s_tab.phases[row] = new_stabrow.phase[])
B && (s_tab.phases[row] = new_stabrow.phase[])
new_stabrow
end

Expand Down
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