From e42b7fcdeb3ead5ad20f5f762946cc6dd7cbb48d Mon Sep 17 00:00:00 2001
From: Fredrik Bagge Carlson <baggepinnen@gmail.com>
Date: Mon, 10 Jan 2022 08:24:45 +0100
Subject: [PATCH] LTISystem parameterized by time evolution

closes #367
---
 src/types/DelayLtiSystem.jl      | 8 ++++----
 src/types/Lti.jl                 | 2 +-
 src/types/PartionedStateSpace.jl | 6 +++---
 src/types/StateSpace.jl          | 2 +-
 src/types/TransferFunction.jl    | 2 +-
 5 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/types/DelayLtiSystem.jl b/src/types/DelayLtiSystem.jl
index 14d5f7162..41050c2d7 100644
--- a/src/types/DelayLtiSystem.jl
+++ b/src/types/DelayLtiSystem.jl
@@ -3,8 +3,8 @@
 
 Represents an LTISystem with internal time-delay. See `?delay` for a convenience constructor.
 """
-struct DelayLtiSystem{T,S<:Real} <: LTISystem
-    P::PartionedStateSpace{StateSpace{Continuous,T}}
+struct DelayLtiSystem{T,S<:Real} <: LTISystem{Continuous}
+    P::PartionedStateSpace{Continuous, StateSpace{Continuous,T}}
     Tau::Vector{S} # The length of the vector tau implicitly defines the partitionging of P
 
     # function DelayLtiSystem(P::StateSpace{Continuous,T, MT}, Tau::Vector{T})
@@ -33,11 +33,11 @@ function DelayLtiSystem{T,S}(sys::StateSpace, Tau::AbstractVector{S} = Float64[]
         throw(ArgumentError("The delay vector of length $length(Tau) is too long."))
     end
 
-    psys = PartionedStateSpace{StateSpace{Continuous,T}}(sys, nu, ny)
+    psys = PartionedStateSpace{Continuous, StateSpace{Continuous,T}}(sys, nu, ny)
     DelayLtiSystem{T,S}(psys, Tau)
 end
 # For converting DelayLtiSystem{T,S} to different T
-DelayLtiSystem{T}(sys::DelayLtiSystem) where {T} = DelayLtiSystem{T}(PartionedStateSpace{StateSpace{Continuous,T}}(sys.P), Float64[])
+DelayLtiSystem{T}(sys::DelayLtiSystem) where {T} = DelayLtiSystem{T}(PartionedStateSpace{Continuous, StateSpace{Continuous,T}}(sys.P), Float64[])
 DelayLtiSystem{T}(sys::StateSpace) where {T} = DelayLtiSystem{T, Float64}(sys, Float64[])
 
 # From StateSpace, infer type
diff --git a/src/types/Lti.jl b/src/types/Lti.jl
index 9bb3653e5..654a470da 100644
--- a/src/types/Lti.jl
+++ b/src/types/Lti.jl
@@ -1,4 +1,4 @@
-abstract type LTISystem <: AbstractSystem end
+abstract type LTISystem{TE<:TimeEvolution} <: AbstractSystem end
 +(sys1::LTISystem, sys2::LTISystem) = +(promote(sys1, sys2)...)
 -(sys1::LTISystem, sys2::LTISystem) = -(promote(sys1, sys2)...)
 *(sys1::LTISystem, sys2::LTISystem) = *(promote(sys1, sys2)...)
diff --git a/src/types/PartionedStateSpace.jl b/src/types/PartionedStateSpace.jl
index 99a6420d0..3528d7985 100644
--- a/src/types/PartionedStateSpace.jl
+++ b/src/types/PartionedStateSpace.jl
@@ -11,14 +11,14 @@ u = [u1 u2]^T
 y = [y1 y2]^T
 
 """
-struct PartionedStateSpace{S<:AbstractStateSpace} <: LTISystem
+struct PartionedStateSpace{TE<:TimeEvolution, S<:AbstractStateSpace{TE}} <: LTISystem{TE}
     P::S
     nu1::Int
     ny1::Int
 end
 # For converting between different S
-PartionedStateSpace{S}(partsys::PartionedStateSpace) where {S<:StateSpace} =
-    PartionedStateSpace{S}(S(partsys.P), partsys.nu1, partsys.ny1)
+PartionedStateSpace{TE, S}(partsys::PartionedStateSpace{TE}) where {TE, S<:StateSpace} =
+    PartionedStateSpace{TE, S}(S(partsys.P), partsys.nu1, partsys.ny1)
 
 function getproperty(sys::PartionedStateSpace, d::Symbol)
     P = getfield(sys, :P)
diff --git a/src/types/StateSpace.jl b/src/types/StateSpace.jl
index 8dfadaf5a..717052e5d 100644
--- a/src/types/StateSpace.jl
+++ b/src/types/StateSpace.jl
@@ -22,7 +22,7 @@ function state_space_validation(A,B,C,D)
     nx,nu,ny
 end
 
-abstract type AbstractStateSpace{TE<:TimeEvolution} <: LTISystem end
+abstract type AbstractStateSpace{TE<:TimeEvolution} <: LTISystem{TE} end
 
 struct StateSpace{TE, T} <: AbstractStateSpace{TE}
     A::Matrix{T}
diff --git a/src/types/TransferFunction.jl b/src/types/TransferFunction.jl
index 7c5bfc461..29175158a 100644
--- a/src/types/TransferFunction.jl
+++ b/src/types/TransferFunction.jl
@@ -1,4 +1,4 @@
-struct TransferFunction{TE, S<:SisoTf{T} where T} <: LTISystem
+struct TransferFunction{TE, S<:SisoTf{T} where T} <: LTISystem{TE}
     matrix::Matrix{S}
     timeevol::TE
     nu::Int