private double PrepareRestart(NativeVector rhs, NativeVector x, int jH)
{
ConstructCurrentSolution(jH, x);
double beta;
if (Parameters.ResidualAtRestart == ResidualAtRestart.ComputeTheTrue)
{
UnsafeNativeMethods.Zcopy(_nloc, x.Ptr, _w.Ptr);
CalculateMatrixVectorMult(_w, _r0);
NativeVector.Sub(rhs, _r0, _r0);
if (Parameters.Preconditioning != Preconditioning.None)
{
throw new NotImplementedException();
}
UnsafeNativeMethods.Zcopy(_nloc, _r0.Ptr, _w.Ptr);
beta = CalculateVectorNorm(_w);
}
else
{
beta = _hessenberg[_m, _m].Magnitude;
for (int j = _m - 1; j >= 0; j--)
{
_hessenberg[j, _m] = Zero;
Zrot(_hessenberg.GetPointer(j, _m), _hessenberg.GetPointer(j + 1, _m), _givensRotCos[j], -_givensRotSin[j]);
UnsafeNativeMethods.ZgemvNotTrans(_nloc, _m + 1, One, _krylovBasis.Ptr, _hessenberg.GetColumn(_m), Zero, _w.Ptr);
}
}
return(beta);
}
private double ModifiedGramSchmidtIteration(int jH)
{
double dloo = 0;
for (int j = 0; j <= jH; j++)
{
CalculateDotProduct(_krylovBasis.GetColumn(j), _w.Ptr);
var dVi = _dotProducts[0];
_hessenberg[j, jH] += dVi;
dloo += Abs(dVi) * Abs(dVi);
UnsafeNativeMethods.Zaxpy(_nloc, -dVi, _krylovBasis.GetColumn(j), 1, _w.Ptr, 1);
}
return(dloo);
}