# naginterfaces.library.ode.ivp_​stiff_​sparjac_​enq¶

naginterfaces.library.ode.ivp_stiff_sparjac_enq(comm)[source]

ivp_stiff_sparjac_enq is an enquiry function for communicating with ivp_stiff_exp_revcom() or ivp_stiff_imp_revcom() when supplying columns of a sparse Jacobian matrix.

For full information please refer to the NAG Library document for d02nr

https://www.nag.com/numeric/nl/nagdoc_28.6/flhtml/d02/d02nrf.html

Parameters
commdict, communication object

Communication structure.

This argument must have been initialized by a prior call to ivp_stiff_exp_revcom() or ivp_stiff_imp_revcom().

Returns
jint

The index of the column of the Jacobian which is required.

iplaceint

Indicates which locations in the array to fill with the th column.

If , the th element of the Jacobian must be placed in , otherwise the th element must be placed in .

If , in the previous call to ivp_stiff_sparjac_setup(), always, hence the th column of the Jacobian must be placed in , for .

, and are arguments of ivp_stiff_exp_revcom() and ivp_stiff_imp_revcom().

Notes

No equivalent traditional C interface for this routine exists in the NAG Library.

ivp_stiff_sparjac_enq is required when ivp_stiff_exp_revcom() or ivp_stiff_imp_revcom() is being used with sparse matrix linear algebra. After an exit from ivp_stiff_exp_revcom() or ivp_stiff_imp_revcom() with , ivp_stiff_sparjac_enq must be called to determine which column of the Jacobian is required and where it is to be placed in the array (an argument of ivp_stiff_exp_revcom() or ivp_stiff_imp_revcom()).