bulk implementation of PartialSquare

Author: MartinuzziFrancesco

docs/src/api/states.md

@@ -16,6 +16,7 @@
     NLAT1
     NLAT2
     NLAT3
+    PartialSquare
 ```
 
 ## Internals

src/ReservoirComputing.jl

@@ -33,7 +33,7 @@ include("esn/esn_predict.jl")
 include("reca/reca.jl")
 include("reca/reca_input_encodings.jl")
 
-export NLADefault, NLAT1, NLAT2, NLAT3
+export NLADefault, NLAT1, NLAT2, NLAT3, PartialSquare
 export StandardStates, ExtendedStates, PaddedStates, PaddedExtendedStates
 export StandardRidge
 export scaled_rand, weighted_init, informed_init, minimal_init, chebyshev_mapping,

src/states.jl

@@ -654,3 +654,20 @@ function (::NLAT3)(x_old::AbstractVector)
 
     return x_new
 end
+
+struct PartialSquare <: NonLinearAlgorithm
+    eta::Number
+end
+
+function (ps::PartialSquare)(x_old::AbstractVector)
+    x_new = copy(x_old)
+    n_length = length(x_old)
+    threshold = floor(Int, ps.eta * n_length)
+    for idx in eachindex(x_old)
+        if idx <= threshold
+            x_new[idx] = x_old[idx]^2
+        end
+    end
+    
+    return x_new
+end

test/test_states.jl

@@ -8,7 +8,8 @@ test_types = [Float64, Float32, Float16]
 nlas = [(NLADefault(), test_array),
     (NLAT1(), [1, 2, 9, 4, 25, 6, 49, 8, 81]),
     (NLAT2(), [1, 2, 2, 4, 12, 6, 30, 8, 9]),
-    (NLAT3(), [1, 2, 8, 4, 24, 6, 48, 8, 9])]
+    (NLAT3(), [1, 2, 8, 4, 24, 6, 48, 8, 9]),
+    (PartialSquare(0.6), [1, 4, 9, 16, 25, 6, 7, 8, 9])]
 
 pes = [(StandardStates(), test_array),
     (PaddedStates(; padding=padding),