JacActionCtx — PETSc 3.25.4 documentation

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# JacActionCtx

Application context used by matrix-free `DMPLEX` examples to compute the action of a Jacobian at a fixed base state on a vector

## Synopsis

    typedef struct {
      DM    dm;
      Vec   u; /* The base vector for the Jacobian action J(u) x */
      Mat   J; /* Preconditioner for testing */
      void *user;
    } JacActionCtx;

## Note

Holds the `DM` defining the discretization, the base state vector `u` at which the Jacobian is linearized, an optional assembled `J` used as a preconditioner or for testing, and a pointer to the user’s own application context. Created and consumed by example codes rather than the core PETSc library.

## See Also

`DMPLEX`, `Mat`, `MATSHELL`, `DMPlexComputeJacobianActionByKey()`

## Level

developer

## Location

include/petscdmplex.h

## Examples

src/snes/tutorials/ex12.c

Index of all DMPlex routines
Table of Contents for all manual pages
Index of all manual pages