remove code related to julia 1.6 compatibility

Author: franckgaga

src/estimator/kalman.jl

@@ -38,11 +38,15 @@ struct SteadyKalmanFilter{NT<:Real, SM<:LinModel} <: StateEstimator{NT}
         Â, B̂u, Ĉ, B̂d, D̂d, x̂op, f̂op = augment_model(model, As, Cs_u, Cs_y)
         Ĉm, D̂dm = Ĉ[i_ym, :], D̂d[i_ym, :]
         validate_kfcov(nym, nx̂, Q̂, R̂)
+        if ny == nym
+            R̂_y = R̂
+        else
+            R̂_y = zeros(NT, ny, ny)
+            R̂_y[i_ym, i_ym] = R̂
+            R̂_y = Hermitian(R̂_y, :L)
+        end
         K̂ = try
-            Q̂_kalman = Matrix(Q̂) # Matrix() required for Julia 1.6
-            R̂_kalman = zeros(NT, ny, ny)
-            R̂_kalman[i_ym, i_ym] = R̂
-            ControlSystemsBase.kalman(Discrete, Â, Ĉ, Q̂_kalman, R̂_kalman; direct)[:, i_ym] 
+            ControlSystemsBase.kalman(Discrete, Â, Ĉ, Q̂, R̂_y; direct)[:, i_ym]
         catch my_error
             if isa(my_error, ErrorException)
                 error("Cannot compute the optimal Kalman gain K̂ for the "* 

src/model/solver.jl

@@ -47,13 +47,11 @@ function get_solver_functions(NT::DataType, solver::RungeKutta, fc!, hc!, Ts, _
     k4_cache::DiffCache{Vector{NT}, Vector{NT}}   = DiffCache(zeros(NT, nx), Nc)
     f! = function inner_solver_f!(xnext, x, u, d, p)
         CT = promote_type(eltype(x), eltype(u), eltype(d))
-        # dummy variable for get_tmp, necessary for PreallocationTools + Julia 1.6 :
-        var::CT = 0
-        xcur = get_tmp(xcur_cache, var)
-        k1   = get_tmp(k1_cache, var)
-        k2   = get_tmp(k2_cache, var)
-        k3   = get_tmp(k3_cache, var)
-        k4   = get_tmp(k4_cache, var)
+        xcur = get_tmp(xcur_cache, CT)
+        k1   = get_tmp(k1_cache, CT)
+        k2   = get_tmp(k2_cache, CT)
+        k3   = get_tmp(k3_cache, CT)
+        k4   = get_tmp(k4_cache, CT)
         xterm = xnext
         @. xcur = x
         for i=1:solver.supersample