Module Arkode.Dls

Callback functions that compute dense approximations to a Jacobian matrix. In the call jac arg jm, arg is a Arkode.Common.jacobian_arg with three work vectors and the computed Jacobian must be stored in jm.

The callback should load the (i,j)th entry of jm with $\partial (f_I)_i/\partial y_j$, i.e., the partial derivative of the ith implicit equation with respect to the jth variable, evaluated at the values of t and y obtained from arg. Only nonzero elements need be loaded into jm.

Raising Sundials.RecoverableFailure indicates a recoverable error. Any other exception is treated as an unrecoverable error.

Function to compute the linear system matrix $A = M - \gamma J$ or an approximation of it. Offers an alternative to evaluating the Jacobian of the right-hand-side function.

In addition to those shared with the Jacobian function, the arguments of this function are

• a, storage for the computed linear system matrix,
• m, the current mass matrix if $M \neq I$ ,
• jok, indicates whether the Jacobian-related data needs to be updated, and
• gamma, the scalar in the formula above.

The function should return true only if the Jacobian data was recomputed.

Raising Sundials.RecoverableFailure indicates a recoverable error. Any other exception is treated as an unrecoverable error.