Begin implementation of null (ITensor#128)

Author: mtfishman

Project.toml

@@ -1,7 +1,7 @@
 name = "BlockSparseArrays"
 uuid = "2c9a651f-6452-4ace-a6ac-809f4280fbb4"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
-version = "0.6.7"
+version = "0.6.8"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"

src/factorizations/orthnull.jl

@@ -1,9 +1,15 @@
 using MatrixAlgebraKit:
   MatrixAlgebraKit,
+  default_svd_algorithm,
+  left_null!,
+  left_null_svd!,
   left_orth!,
   left_polar!,
   lq_compact!,
+  null_truncation_strategy,
   qr_compact!,
+  right_null!,
+  right_null_svd!,
   right_orth!,
   right_polar!,
   select_algorithm,
@@ -122,3 +128,50 @@ function MatrixAlgebraKit.right_orth_svd!(A::AbstractBlockSparseMatrix, F, alg,
   U, S, Vᴴ = svd_trunc!(A, alg_trunc)
   return U * S, Vᴴ
 end
+
+function MatrixAlgebraKit.initialize_output(
+  ::typeof(left_null!), A::AbstractBlockSparseMatrix
+)
+  return nothing
+end
+function MatrixAlgebraKit.check_input(
+  ::typeof(left_null!), A::AbstractBlockSparseMatrix, N::Nothing
+)
+  return nothing
+end
+function MatrixAlgebraKit.left_null_qr!(A::AbstractBlockSparseMatrix, N, alg)
+  return left_null_svd!(A, N, default_svd_algorithm(A))
+end
+function MatrixAlgebraKit.left_null_svd!(
+  A::AbstractBlockSparseMatrix, N, alg, trunc::Nothing
+)
+  return left_null_svd!(A, N, alg, null_truncation_strategy(; atol=0, rtol=0))
+end
+function MatrixAlgebraKit.truncate!(
+  ::typeof(left_null!),
+  (U, S)::Tuple{AbstractBlockSparseMatrix,AbstractBlockSparseMatrix},
+  strategy::TruncationStrategy,
+)
+  return error("Not implemented.")
+end
+
+function MatrixAlgebraKit.initialize_output(
+  ::typeof(right_null!), A::AbstractBlockSparseMatrix
+)
+  return nothing
+end
+function MatrixAlgebraKit.check_input(
+  ::typeof(right_null!), A::AbstractBlockSparseMatrix, N::Nothing
+)
+  return nothing
+end
+function MatrixAlgebraKit.right_null_lq!(A::AbstractBlockSparseMatrix, N, alg)
+  return error("Not implement.")
+end
+function MatrixAlgebraKit.truncate!(
+  ::typeof(right_null!),
+  (S, Vᴴ)::Tuple{AbstractBlockSparseMatrix,AbstractBlockSparseMatrix},
+  strategy::TruncationStrategy,
+)
+  return error("Not implemented.")
+end

src/factorizations/qr.jl

@@ -1,8 +1,9 @@
-using MatrixAlgebraKit: MatrixAlgebraKit, lq_compact!, lq_full!, qr_compact!, qr_full!
+using MatrixAlgebraKit:
+  MatrixAlgebraKit, default_qr_algorithm, lq_compact!, lq_full!, qr_compact!, qr_full!
 
 # TODO: this is a hardcoded for now to get around this function not being defined in the
 # type domain
-function default_blocksparse_qr_algorithm(A::AbstractMatrix; kwargs...)
+function MatrixAlgebraKit.default_qr_algorithm(A::AbstractBlockSparseMatrix; kwargs...)
   blocktype(A) <: StridedMatrix{<:LinearAlgebra.BLAS.BlasFloat} ||
     error("unsupported type: $(blocktype(A))")
   alg = MatrixAlgebraKit.LAPACK_HouseholderQR(; kwargs...)
@@ -11,12 +12,12 @@ end
 function MatrixAlgebraKit.default_algorithm(
   ::typeof(qr_compact!), A::AbstractBlockSparseMatrix; kwargs...
 )
-  return default_blocksparse_qr_algorithm(A; kwargs...)
+  return default_qr_algorithm(A; kwargs...)
 end
 function MatrixAlgebraKit.default_algorithm(
   ::typeof(qr_full!), A::AbstractBlockSparseMatrix; kwargs...
 )
-  return default_blocksparse_qr_algorithm(A; kwargs...)
+  return default_qr_algorithm(A; kwargs...)
 end
 
 function similar_output(

src/factorizations/svd.jl

@@ -1,4 +1,4 @@
-using MatrixAlgebraKit: MatrixAlgebraKit, svd_compact!, svd_full!
+using MatrixAlgebraKit: MatrixAlgebraKit, default_svd_algorithm, svd_compact!, svd_full!
 
 """
     BlockPermutedDiagonalAlgorithm(A::MatrixAlgebraKit.AbstractAlgorithm)
@@ -12,7 +12,7 @@ struct BlockPermutedDiagonalAlgorithm{A<:MatrixAlgebraKit.AbstractAlgorithm} <:
   alg::A
 end
 
-function default_blocksparse_svd_algorithm(f, A; kwargs...)
+function MatrixAlgebraKit.default_svd_algorithm(A; kwargs...)
   blocktype(A) <: StridedMatrix{<:LinearAlgebra.BLAS.BlasFloat} ||
     error("unsupported type: $(blocktype(A))")
   # TODO: this is a hardcoded for now to get around this function not being defined in the
@@ -25,12 +25,12 @@ end
 function MatrixAlgebraKit.default_algorithm(
   f::typeof(svd_compact!), A::AbstractBlockSparseMatrix; kwargs...
 )
-  return default_blocksparse_svd_algorithm(f, A; kwargs...)
+  return default_svd_algorithm(A; kwargs...)
 end
 function MatrixAlgebraKit.default_algorithm(
   f::typeof(svd_full!), A::AbstractBlockSparseMatrix; kwargs...
 )
-  return default_blocksparse_svd_algorithm(f, A; kwargs...)
+  return default_svd_algorithm(A; kwargs...)
 end
 
 function similar_output(