jac_prototype

Stable function · Evaluate the Jacobian

Tier: stable · Kind: function · Topic: Evaluate the Jacobian

Julia	Python	Rust
`jac_prototype`	not exported	not exported

Julia

jac_prototype(jac::JacobianEvaluator)
jac_prototype(input; wrt, model_name)

jac_prototype(jac::JacobianEvaluator) -> SparseMatrixCSC{Float64,Int}
jac_prototype(input; wrt = :states, model_name = nothing)

A freshly zeroed sparse prototype on the structural pattern — the object to pass as ODEFunction(f!; jac_prototype = …). Stored (structural) zeros are kept so the pattern is point-independent.

Source

Example (prepare)

jac = prepare_jacobian(file)                 # differentiate and compile once
J = jac_prototype(jac)                       # sparse matrix on the fixed pattern
u = fill(2.0, 12)
p = jac.p_default                            # the document's parameter values
jac(J, u, p, 0.0)                            # fill J in place, at any (u, p, t)
@assert size(J) == (12, 12)
@assert nnz(J) == 24
@assert J[1, 1] == -0.04