fixed compatibility issues and missing file

Author: rittermarc

Project.toml

@@ -20,10 +20,10 @@ TCIITensorConversion = ["ITensors", "ITensorMPS"]
 [compat]
 BitIntegers = "0.3.5"
 EllipsisNotation = "1"
-ITensorMPS = "0.3"
-ITensors = "0.7, 0.8, 0.9"
+ITensorMPS = "0.2, 0.3"
+ITensors = "0.6, 0.7, 0.8, 0.9"
 QuadGK = "2.9"
-Random = "1.10.0"
+Random = "1.9.0"
 julia = "1.9"
 
 [extras]
@@ -37,4 +37,4 @@ Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 
 [targets]
-test = ["Aqua", "Test", "Random", "ITensors", "Zygote", "Optim", "QuanticsGrids", "JET"]
+test = ["Aqua", "Test", "Random", "ITensors", "ITensorMPS", "Zygote", "Optim", "QuanticsGrids", "JET"]

docs/src/extensions.md

@@ -0,0 +1,17 @@
+# Extensions
+
+This page documents extensions to [TensorCrossInterpolation](https://github.com/tensor4all/TensorCrossInterpolation.jl).
+
+Currently, there is only one extension, TCIITensorConversion.
+
+## TCIITensorConversion
+
+Dependencies:
+- [ITensors.jl](https://github.com/ITensor/ITensors.jl)
+- [ITensorMPS.jl](https://github.com/ITensor/ITensorMPS.jl)
+
+This module is automatically loaded when ITensors and ITensorMPS are present in addition to TensorCrossInterpolation. It offers conversion constructors between ITensorMPS types and TensorCrossInterpolation types, and an analogue of the [`evaluate`](@ref) function for ITensor types.
+
+```@autodocs
+Modules = [Base.get_extension(TensorCrossInterpolation, :TCIITensorConversion)]
+```

ext/TCIITensorConversion/mpsutil.jl

@@ -0,0 +1,50 @@
+@doc raw"""
+    function evaluate(
+        mps::Union{ITensorMPS.MPS,ITensorMPS.MPO},
+        indexspecs::Vararg{AbstractVector{<:Tuple{ITensorMPS.Index,Int}}}
+    )
+
+Evaluates an MPS or MPO for a given set of index values.
+
+- `indexspec` is a list of tuples, where each tuple contains an `ITensorMPS.Index` object specifying an index, and an `Int` corresponding to the value of the specified index.
+
+If many evaluations are necessary, it may be advantageous to convert your MPS to a [`TensorCrossInterpolation.TTCache`](@ref) object first.
+"""
+function evaluate(
+    mps::Union{ITensorMPS.MPS,ITensorMPS.MPO},
+    indexspecs::Vararg{AbstractVector{<:Tuple{ITensors.Index,Int}}}
+)
+    if isempty(indexspecs)
+        error("Please specify at which indices you wish to evaluate the MPS.")
+    elseif any(length.(indexspecs) .!= length(mps))
+        error("Need one index per MPS leg")
+    end
+
+    V = ITensor(1.0)
+    for j in eachindex(indexspecs[1])
+        states = prod(ITensorMPS.state(spec[j]...) for spec in indexspecs)
+        V *= mps[j] * states
+    end
+    return scalar(V)
+end
+@doc raw"""
+    function evaluate(
+        mps::Union{ITensorMPS.MPS,ITensorMPS.MPO},
+        indices::AbstractVector{<:ITensors.Index},
+        indexvalues::AbstractVector{Int}
+    )
+
+Evaluates an MPS or MPO for a given set of index values.
+
+- `indices` is a list of `ITensors.Index` objects that specifies the order in which indices are given.
+- `indexvalues` is a list of integer values in the same order as `indices`.
+
+If many evaluations are necessary, it may be advantageous to convert your MPS to a [`TensorCrossInterpolation.TTCache`](@ref) object first.
+"""
+function evaluate(
+    mps::Union{ITensorMPS.MPS,ITensorMPS.MPO},
+    indices::AbstractVector{<:ITensors.Index},
+    indexvalues::AbstractVector{Int}
+)
+    return evaluate(mps, collect(zip(indices, indexvalues)))
+end