744 Methods for Solving Grid EquationsIf R = R1 + R2, R:, =Ru:> 0 and R1 R2 = R2 Ri ADNI frmn Section
4, items 2-3 inay be employee!, where the inini1num condition for the work
in connection with solving the equation Au = f guides a proper choice of
the quantity q.
vVhen the spectrum of R happens to be unknown in advance, it seems
worthwhile adapting iterative methods of variational type for determination
of the correction. Unfortunately, in this book we have no possibility to say
n10re about other cmnbinations arising time and again in such inatters.