int KINSpilsDQJtimes(N_Vector v, N_Vector Jv,
N_Vector u, booleantype *new_u,
void *data)
{
realtype sigma, sigma_inv, sutsv, sq1norm, sign, vtv;
KINMem kin_mem;
KINSpilsMem kinspils_mem;
int retval;
/* data is kin_mem */
kin_mem = (KINMem) data;
kinspils_mem = (KINSpilsMem) lmem;
/* scale the vector v and put Du*v into vtemp1 */
N_VProd(v, uscale, vtemp1);
/* scale u and put into Jv (used as a temporary storage) */
N_VProd(u, uscale, Jv);
/* compute dot product (Du*u).(Du*v) */
sutsv = N_VDotProd(Jv, vtemp1);
/* compute dot product (Du*v).(Du*v) */
vtv = N_VDotProd(vtemp1, vtemp1);
sq1norm = N_VL1Norm(vtemp1);
sign = (sutsv >= ZERO) ? ONE : -ONE ;
/* this expression for sigma is from p. 469, Brown and Saad paper */
sigma = sign*sqrt_relfunc*SUNMAX(SUNRabs(sutsv),sq1norm)/vtv;
sigma_inv = ONE/sigma;
/* compute the u-prime at which to evaluate the function func */
N_VLinearSum(ONE, u, sigma, v, vtemp1);
/* call the system function to calculate func(u+sigma*v) */
retval = func(vtemp1, vtemp2, user_data);
nfes++;
if (retval != 0) return(retval);
/* finish the computation of the difference quotient */
N_VLinearSum(sigma_inv, vtemp2, -sigma_inv, fval, Jv);
return(0);
}
realtype N_VL1Norm_SensWrapper(N_Vector x)
{
int i;
realtype nrm, tmp;
nrm = ZERO;
for (i=0; i < NV_NVECS_SW(x); i++) {
tmp = N_VL1Norm(NV_VEC_SW(x,i));
if (tmp > nrm) nrm = tmp;
}
return(nrm);
}
