Merge branch '43-tto-tto-contraction' into 'main'

Resolve "TTO-TTO contraction"

Closes #43

See merge request tensors4fields/TensorCrossInterpolation.jl!82

Author: Marc Ritter

docs/src/documentation.md

@@ -28,7 +28,7 @@ Pages = ["matrixlu.jl", "matrixluci.jl"]
 ### Tensor train (TT)
 ```@autodocs
 Modules = [TensorCrossInterpolation]
-Pages = ["abstracttensortrain.jl", "tensortrain.jl"]
+Pages = ["abstracttensortrain.jl", "tensortrain.jl", "contraction.jl"]
 ```
 
 ### Tensor cross interpolation (TCI)

src/TensorCrossInterpolation.jl

@@ -14,7 +14,9 @@ import Base: isempty, iterate, getindex, lastindex, broadcastable
 import Base: length, size, sum
 
 export crossinterpolate1, crossinterpolate2, optfirstpivot
-export tensortrain
+export tensortrain, TensorTrain, sitedims, evaluate
+
+export contract
 
 include("util.jl")
 include("sweepstrategies.jl")
@@ -33,5 +35,6 @@ include("tensorci2.jl")
 include("tensortrain.jl")
 include("conversion.jl")
 include("integration.jl")
+include("contraction.jl")
 
 end