1 Motivation SLIDE 1 Consider a standard second order finite difference discretization of V-u= on a regular g 1.2. and 3 dimensions 1.1 1D Finite differences

Governing Equation Stability Analysis 3 Examples Relationship between σ and λh Implicit Time-Marching Scheme

Outline Governing Equation Stability Analysis 3 Examples Relationship between σ and λh Implicit Time-Marching Scheme

1 Finite difference formulas 1.1 Problem definition We have seen that one of the necessary ingredients in devising finite differe

Finite Difference Problem Definition Formulas

Poisson Equation in 1D Model Problem Boundary Value Problem(BVP) Wra(ac)= f(a) N1 x∈(0,1),w(0)=(1)=0,f∈C0N2 Describes many simple physical phen

())/0=),6()/+2g= edrhugdr)/2M),oxdx) o: Elex Enwk'< uz=x), a(z qurgdiea= uuv y= adwvopu)z(o j): ac=2 Ghwceo(udo: 2M( Hw(uy 0: w cloks rE o Chu Tnr(i b)iwgiffadu cu wa rdo h ouno pk- which wite pexy a ca)=dre halfan a)+x=gub)whwxppdpxiv z=ioy u)udre Wwv ay co)(igad )o)a)i o u v( wh

1 Motivation The Poisson problem has a strong formulation a minimization formulation and a weak formulation T weak formulations are more general than the strong formulation in terms of regularity and admissible data SLIDE 2 The minimization/weak formulations are defined by: a space X; a bilinear The minimization/weak formulations identify ESSENTIAL boundary conditions NATURAL boundary conditions ed in a The points of departure for the finite element method are the weak formulation(more generally) the minimization statement (if a is SPD) 2 The dirichlet problem 2.1 Strong Formulation Find u such that

Dirichlet Model Problems Strong Form Domain: Q =(0, 1) Find u such that (0)=(1)=0 for given f SMA-HPO⊙1999M Poisson in Rl. Formulation 1

A posteriori error estimates are arguably more useful than a priori esti mates since we know uh. Bear in mind, however, that (i) in most methods