How to evaluate(substitute numerical values of params n states) a jacobian in modelingtoolkit using generate_jacobian or calculate_jacobian?

General Usage
1

i found that ModelingToolkit.calculate_jacobian() function symbolically generates Jacobian of ODESystem in MTK docs.
How does one substitute numerical values of parameters and state varables numerical values in this matrix to evaluate ?

1 Like
2

Try Symbolics.substitute

3

thanks @baggepinnen
i am doing currently following

x₀map = states(odesys) .=> x0
pmap  = parameters(odesys) .=> ps
jac = substitute.( ModelingToolkit.calculate_jacobian(odesys), (Dict([x₀map;pmap]),) )
jac = Symbolics.value.(jac)

Hope i am doing this right!

4

Looks about right to me, just make sure the states and parameters are returned in the order you expect. :smiley: