Overview#

The Julia API exposes MICM gas-phase chemistry and is built on top of the C++ library using CxxWrap.jl. For installation, see Julia.

Defining a Mechanism#

Mechanisms are loaded from a mechanism configuration file directory. Use the bundled configs/v0/analytical example or provide your own:

using MUSICA

solver = MICM("configs/v0/analytical", SolverType.rosenbrock_standard_order)

Creating a Solver#

The solver type is the second argument to MICM. Available options via the SolverType enum:

Solver	Description
`SolverType.rosenbrock_standard_order`	Rosenbrock solver (standard species ordering)
`SolverType.rosenbrock_arbitrary_order`	Rosenbrock solver (arbitrary species ordering)
`SolverType.backward_euler_standard_order`	Backward Euler solver (standard species ordering)
`SolverType.backward_euler_arbitrary_order`	Backward Euler solver (arbitrary species ordering)

Setting Conditions#

Create a state and set concentrations and environmental conditions:

state = create_state(solver)

set_concentrations!(state, Dict("A" => 1.0, "B" => 3.0, "C" => 5.0))
set_conditions!(state, 300.0, 101000.0)   # temperature (K), pressure (Pa)

Solving#

Call solve! at each time step:

time_step  = 4.0    # s
sim_length = 20.0   # s
curr_time  = time_step

while curr_time <= sim_length
    solve!(solver, state, time_step)
    curr_time += time_step
end

Accessing Results#

Retrieve updated concentrations from the state after each solve:

conc = get_concentrations(state)
println("A=$(conc["A"][1])  B=$(conc["B"][1])  C=$(conc["C"][1])")

Note

TUV-x photolysis and CARMA aerosol support are not yet available in the Julia API.