Restrict size of input parameters (#770)

* Restrict size of input parameters

* Add tests

Co-authored-by: Michele Zaffalon <michele.zaffalon@bruker.com>

Author: mzaffalon

src/timeresp.jl

@@ -23,12 +23,14 @@ function lsim(sys::AbstractStateSpace{Continuous}, u::Function, t::AbstractVecto
         x0::AbstractVecOrMat=zeros(Bool, nstates(sys)), method::Symbol=:cont, alg = Tsit5(), kwargs...)
     ny, nu = size(sys)
     nx = sys.nx
-    u0 = u(x0,1)
-    if length(x0) != nx
+    u0 = u(x0,t[1])
+    length(x0) == nx ||
         error("x0 must have length $nx: got length $(length(x0))")
-    elseif !(u0 isa Number && nu == 1) && (size(u0) != (nu,) && size(u0) != (nu,1))
+    isa(u0, Number) &&
+        error("u must be a vector of size ($nu,)")
+    size(u0) == (nu,) ||
         error("u must have size ($nu,): got size $(size(u0))")
-    end
+
     T = promote_type(Float64, eltype(x0), numeric_type(sys))
 
     dt = t[2] - t[1]
@@ -414,4 +416,4 @@ function _lsim(sys::HammersteinWienerSystem{T}, u!, t::AbstractArray{<:Real}, x0
     end
 
     return SimResult(yout, t, x, uout2, sys)
-end
+end

test/test_timeresp.jl

@@ -23,6 +23,11 @@ th = 1e-6
 # Error for wrong size of u
 @test_throws ErrorException lsim(sys, (x,t)->[sin(t), cos(t)], 2; x0=[0, 1])
 
+# Restrict u to being vectors
+@test_throws ErrorException lsim(sys, (x,t)->[sin(t)]', 0:0.1:1)
+@test_throws ErrorException lsim(sys, (x,t)->[sin(t)]', 2)
+@test_throws ErrorException lsim(sys, (x,t)->sin(t), 2)
+
 # Error for wrong size of x0
 @test_throws ErrorException lsim(sys, (x,t)->[sin(t)], 2; x0=[0, 1, 1])
 
@@ -123,4 +128,4 @@ for balanced in [true, false]
     sys2 = time_scale(sys, a; balanced)
     res2 = step(sys2, t ./ a)
     @test res1.y ≈ res2.y rtol=1e-2 atol=1e-2
-end
+end