D03PYF may be used in conjunction with either D03PDF/D03PDA
. It computes the solution and its first derivative at user-specified points in the spatial coordinate.
|SUBROUTINE D03PYF (
||NPDE, U, NBKPTS, XBKPTS, NPOLY, NPTS, XP, INTPTS, ITYPE, UP, RSAVE, LRSAVE, IFAIL)
||NPDE, NBKPTS, NPOLY, NPTS, INTPTS, ITYPE, LRSAVE, IFAIL
||U(NPDE,NPTS), XBKPTS(NBKPTS), XP(INTPTS), UP(NPDE,INTPTS,ITYPE), RSAVE(LRSAVE)
D03PYF is an interpolation routine for evaluating the solution of a system of partial differential equations (PDEs), or the PDE components of a system of PDEs with coupled ordinary differential equations (ODEs), at a set of user-specified points. The solution of a system of equations can be computed using D03PDF/D03PDA
on a set of mesh points; D03PYF can then be employed to compute the solution at a set of points other than those originally used in D03PDF/D03PDA
. It can also evaluate the first derivative of the solution.
Polynomial interpolation is used between each of the break points
. When the derivative is needed (
), the array
must not contain any of the break points, as the method, and consequently the interpolation scheme, assumes that only the solution is continuous at these points.
the parameters U
must be supplied unchanged from either D03PDF/D03PDA
If on entry
, explanatory error messages are output on the current error message unit (as defined by X04AAF