jacobian function

plus duffing fix

Author: Datseris

src/continuous.jl

@@ -103,6 +103,8 @@ dimension(ds::ContinuousDS) = length(ds.prob.u0)
 Base.eltype(ds::ContinuousDS{T,F,J}) where {T, F, J} = T
 state(ds::ContinuousDS) = ds.prob.u0
 
+jacobian(ds::ContinuousDynamicalSystem) = (ds.jacob!(0, state(ds), ds.J); ds.J)
+
 #######################################################################################
 #                         Interface to DifferentialEquations                          #
 #######################################################################################

src/discrete.jl

@@ -1,6 +1,6 @@
 using StaticArrays, ForwardDiff, Requires
 
-export DiscreteDS, DiscreteDS1D, evolve, trajectory, dimension, state
+export DiscreteDS, DiscreteDS1D, evolve, trajectory, dimension, state, jacobian
 export BigDiscreteDS, DiscreteDynamicalSystem
 
 #####################################################################################
@@ -135,14 +135,14 @@ dimension(::DiscreteDS1D) = 1
 dimension(ds::BigDiscreteDS) = length(state(ds))
 
 """
-    jacobian(ds::DynamicalSystem)
+    jacobian(ds::DynamicalSystem) -> J
 Return the Jacobian matrix of the equations of motion at the system's state.
 """
-jacobian(ds::DynamicalSystem) = (ds.jacob!(ds.J, state(ds)), ds.J)
+jacobian(ds::DynamicalSystem) = (ds.jacob!(ds.J, state(ds)); ds.J)
 jacobian(ds::DiscreteDS) = ds.jacob(state(ds))
 
 """
-    state(ds::DynamicalSystem)
+    state(ds::DynamicalSystem) -> u
 Return the state of the system.
 """
 state(ds::DynamicalSystem) = ds.state

src/famous_systems.jl

@@ -272,7 +272,7 @@ end
 end
 @inbounds function (duf::Duffing)(t, u::AbstractVector, J::AbstractMatrix)
     J[2,1] = -duf.β - 3u[1]^2
-    J[2,2] = -duf.d*u[2]
+    J[2,2] = -duf.d
 end