Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

[ITensorMPS] Bond dimensions produced by randomCircuitMPS #870

Open
wants to merge 9 commits into
base: main
Choose a base branch
from
Open

[ITensorMPS] Bond dimensions produced by randomCircuitMPS #870

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
9 commits
Select commit Hold shift + click to select a range
f3da194
Include the product of local dimensions beginning from the start of t…
Mar 17, 2022
4e436ea
Added test for randomCircuitMPS bond dimensions.
Mar 17, 2022
82a4ea4
Formating.
Mar 17, 2022
d3d81b5
Fixed randomCircuitMPS function name. Use in test for bond dimension.
Apr 5, 2022
76f507e
Merge branch 'main' into main
mtfishman Jun 29, 2022
c2a131a
Fixed test for randomCircuitMPS
Jul 13, 2022
62fa370
Merge branch 'ITensor:main' into main
markusschmitt Jul 13, 2022
62bd58e
Merge branch 'main' of https://github.com/markusschmitt/ITensors.jl
Jul 13, 2022
238e4dc
Tests passing.
Jul 13, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions Project.toml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ version = "0.3.18"
[deps]
BitIntegers = "c3b6d118-76ef-56ca-8cc7-ebb389d030a1"
ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"
Dictionaries = "85a47980-9c8c-11e8-2b9f-f7ca1fa99fb4"
HDF5 = "f67ccb44-e63f-5c2f-98bd-6dc0ccc4ba2f"
Expand Down
19 changes: 16 additions & 3 deletions src/mps/mps.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -148,15 +148,28 @@ function randomCircuitMPS(

l = Vector{Index}(undef, N)

# Compute the bond dimension for each link.
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Would be nice to have this as a separate function, so we could use it other places in the code and simplify the code here.

Maybe linkdims_upper_bound? It doesn't have to be exported, just internal use for now.

# It should be the the minimum of the product of local
# Hilbert space dimensions taken from either end of the chain
# or the `linkdim`.
maxdims = Vector{Int}(undef, N - 1)
maxdims[1] = min(dim(sites[1]), linkdim)
for i in 2:(N - 1)
maxdims[i] = min(maxdims[i - 1] * dim(sites[i]), linkdim)
end
maxdims[N - 1] = min(dim(sites[N]), maxdims[N - 1])
for i in (N - 2):-1:1
maxdims[i] = min(dim(sites[i + 1]) * maxdims[i + 1], maxdims[i])
end

d = dim(sites[N])
chi = min(linkdim, d)
chi = maxdims[N - 1]
l[N - 1] = Index(chi, "Link,l=$(N-1)")
O = NDTensors.random_unitary(ElT, chi, d)
M[N] = itensor(O, l[N - 1], sites[N])

for j in (N - 1):-1:2
chi *= dim(sites[j])
chi = min(linkdim, chi)
chi = maxdims[j - 1]
l[j - 1] = Index(chi, "Link,l=$(j-1)")
O = NDTensors.random_unitary(ElT, chi, dim(sites[j]) * dim(l[j]))
T = reshape(O, (chi, dim(sites[j]), dim(l[j])))
Expand Down
13 changes: 12 additions & 1 deletion test/mps.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -197,6 +197,16 @@ include("util.jl")
@test norm(phic[4]) ≈ 1.0
end

@testset "randomMPS bond dimensions" begin
phi = randomMPS(ComplexF64, sites, 50)
expected_dims = [2, 4, 8, 16, 32, 16, 8, 4, 2]

for i in 1:9
l = linkind(phi, i)
@test dim(l) == expected_dims[i]
end
end

@testset "randomMPS with chi>1" for linkdims in [1, 4]
phi = randomMPS(Float32, sites; linkdims)
@test LinearAlgebra.promote_leaf_eltypes(phi) === Float32
Expand Down Expand Up @@ -482,7 +492,8 @@ include("util.jl")

ϕ2 = +(ψ1, ψ2; alg="directsum")
for j in 1:8
@test linkdim(ϕ2, j) == χ1 + χ2
#@test linkdim(ϕ2, j) == χ1 + χ2
@test linkdim(ϕ2, j) == linkdim(ψ1, j) + linkdim(ψ2, j)
end
@test inner(ϕ2, ψ1) + inner(ϕ2, ψ2) ≈ inner(ϕ2, ϕ2)
end
Expand Down