KSPInitialResidual

Computes the residual.

#include "petscksp.h" 
int KSPInitialResidual(KSP ksp,Vec vsoln,Vec vt1,Vec vt2,Vec vres,Vec vb)

Collective on KSP

	vsoln	- solution to use in computing residual
	vt1, vt2	- temporary work vectors
	vres	- calculated residual
	vb	- right-hand-side vector

This routine assumes that an iterative method, designed for

    A x = b

will be used with a preconditioner, C, such that the actual problem is either

    AC u = f (right preconditioning) or

    CA x = Cf (left preconditioning).

KSP, residual