|
|
|
Study Questions (remaining)
CSci 2031: Introduction to Numerical Computing
Spring 2008
Study Topics (remaining)
The questions below are intended to guide your study of the material
covered in the last part of the course. The final exam will include
topics from this list, along with selected topics from the study
lists given for the previous two midterm exams.
- Section 8.2: Iterative Solutions of Linear Equations
- Be familiar with, and know how to compute, the l1,
l2, and linfinity vector and
matrix norms.
- Be familiar with the concept of, and know how to compute, the
condition number of a matrix. In particular, you should be
able to explain why it can be useful to know the condition number
of a matrix.
- Know why it can be desirable to use a method that provides an
iterative solution to a system of linear equations, as opposed to a
method that directly gives a solution to the system.
- Be able to describe the basic approach used to define an iterative
method for the solution of a system of linear equations (see pages 322-323
of our textbook).
- Be familiar with the equation formulation of the Jacobi, Gauss-Seidel and
SOR iterative methods (pp. 323-324), and be able to use it to determine
successively more accurate estimates (x(1),
x(2), etc.) of the exact solution vector
x for a system of linear equations Ax = b,
given an initial estimated solution vector x(0).
- Given a system of linear equations Ax = b, be able
to determine the non-singular matrix Q, the iterative matrix
B = I - Q-1A,
and the constant vector h = Q-1b
that enable obtaining successive estimates of the solution vector
x using Jacobi iteration. Also, know how to
obtain the corresponding matrices and constant vectors
used in Gauss-Seidel and SOR iteration.
- Be able to describe the similarities/differences/advantages/disadvantages
and applicability of these three methods, including the role played by the factor
ω in the SOR method.
- Be able to determine, for a given system, whether the Jacobi, Gauss-Seidel
and SOR methods are guaranteed to converge. Specifically:
- You should be able to correctly answer questions such as:
- True or False: if A is not strictly diagonally dominant,
then there is no starting vector x(0) for which the Jacobi
method will converge
- True or False: if A is not strictly diagonally dominant,
then it is guaranteed that you will be able to find some starting vector
x(0) for which the Jacobi method will not converge
- True or False: if A is not strictly diagonally dominant,
then the Jacobi method may still converge for all possible starting vectors
x(0)
- You should also be able to use the spectral radius theorem to determine
whether the Jacobi, Gauss-Seidel and SOR methods for the solution of a given
system Ax = b will converge for all initial iterates
x(0) (see pp.348-349)
- Be able to easily and quickly compute the determinant of
a 2x2 matrix. (Hint: The determinant of a matrix A containing the elements
A[i,j], where i denotes the row number and j denotes the column number, and
A[1,1] = a, A[1,2] = b, A[2,1] = c, A[2,2] = d, is given by: ad - cb).
- Be able to easily and quickly compute the determinant of
a 3x3 matrix. (Hint: The determinant of a matrix A containing the elements
A[1,1] = a, A[1,2] = b, A[1,3] = c, A[2,1] = d, A[2,2] = e, A[2,3] = f,
A[3,1] = g, A[3,2] = h, A[3,3] = i is given by: a(ei-fh)-b(di-fg)+c(dh-eg)).
- Section 9.1: First-Degree and Second-Degree Splines
- Be able to explain, in your own words, what a spline is.
- Know the definition of a first-degree spline, and be
able to determine if a given expression represents a first-degree spline.
- Know the definition of a second-degree spline, and be
able to determine if a given expression represents a second-degree spline.
- Be able to determine the first-degree spline S(x) that
interpolates a given set of points.
- Be able to determine the second-degree spline Q(x) that
interpolates a given set of points and that has zero first derivative at the
first point.
- Be able to determine the Subbotin quadratic spline Q(x) that
is defined by a given set of knots, nodes, and values.
- Be able to determine, for a given function f(x), a bound on
the inaccuracy of approximating f(x) by a first-degree spline
p(x) in terms of the maximum distance h between any
successive pair of nodes xi and xi+1
(hint: see theorem 2 on pp.375).
- Section 9.2: Natural Cubic Splines
- Know the definition of a spline of degree k
- Be able to determine whether a given expression represents a spline of
degree k (for arbitrary k).
- Know the definition of a natural cubic spline.
- Know that other types of splines can be defined by setting the two
"extra" constraints in a different way, resulting in curves that have different
characteristic properties.
- Be able to determine the natural cubic spline that
interpolates a given set of points.
- Be able to discuss the relative advantages and disadvantages of
interpolating a table of values using a spline versus using
a single polynomial function.
- Section 9.3: B-Splines and Bezier Splines
- Know how a parametric Bezier spline segment of degree 2 or 3 can be defined
by a collection of three or four control points. [see the notes]
- Know how a uniform, parametric, approximating B spline of degree
1, 2, or 3 can be defined by a collection of control points. [see the notes]
- Chapter 10: Methods for Solving Ordinary Differential Equations
- Be able to exaplin what an initial value problem is.
- Know how to use Euler's method (Taylor series method of order 1) to solve
an initial value problem {dx/dt = f(t,x(t); x(a)=s} to obtain an approximate
value for x(b).
- Be familiar with the 2nd order Runge-Kutta method for solving
an initial value problem {dx/dt = f(t,x(t)); x(a)=s} to obtain an approximate
value for x(b).
- Be familiar with the classical 4th order Runge-Kutta method for
solving an initial value problem {dx/dt = f(t,x(t)); x(a)=s} to obtain an
approximate value for x(b).
Topics that will not be covered on the exam include:
- material from section 8.3 of our textbook
- material from section 8.4 of our textbook
- interpolating B-splines (from section 9.3 of our textbook)
- asking you to solve a specific, given initial value problem using Runge-Kutta methods
|
|