Mathematics 270E







December 3, 2008

"Domain decomposition techniques and the solution of Poisson's equation in infinite domains"

November 9, 2008
Assignment #7 clarifications

  • [1]: The initial condition consists of homogeneous initial data for $\omega$, e.g. $\omega(x,y,0) = 0$.

  • [2](b): Larger grid $\equiv$ more grid panels in each direction.

November 7, 2008


Additional office hour today 2:00-3:00

November 5, 2008

  • Today's office hour is cancelled. Additional office hour times this week will be Friday 2:00-3:00

  • To turn on array bounds checking for the DoubleArray1D and DoubleArray2D array classes:
    • Visual C++ users - compile the project as "debug"
    • Linux/Unix - compile with the preprocessor definition _DEBUG, e.g. specify -D_DEBUG as a compiler option.

October 27, 2008

FFTW information (.pdf)

Assignment 4 Results

Assignment 3 Problem [1] Results (contour plots, surface plots)

Assignment 3 Problem [3] Results (contour plots, surface plots)

October 13, 2008

Assignment 3:

  • Problem [1]: 10% accuracy = $\dfrac{|| Error ||}{||Solution||} \approx .1$
  • Problem [3](c): You many turn in the answer to this question with Assignment 4.

Handout: 270E: Regions of Absolute Stability

Corrected sample for saving plot to .png file: After you save plots to a .png file using GNUplot, you need to reset the terminal type back to the original terminal type when you are done. This instruction was missing from the sample commands given on Sept. 29th. On a MS Windows machine the terminal type is "windows", and on Linux/Unix machine it is whatever terminal type appears when GNUplot is started up (it will tell you this). Sample commands for a MS Windows machine are thus

set term png
set output "GNUplotTestOutput.png"

splot 'Z:\270eCourseDirectory\Assign1\GNUplotTest2D.dat' w l
set term windows

set output

October 8, 2008

Coding constructs in C++ used in Assignment 2

Supplimentary documents for selected topics in C++

On .h, .cpp and .lib files
On preprocessor directives

October 6, 2008

Animations of the exact solution (for one rotation) of the problem being investigated in assignment 2 are available. See

Assignment 2 : Uniform rotation - surface plot
Assignment 2 : Uniform rotation - color contour plot

If you are using Matlab to create plots in assignment 2, then you'll need to modify ConvectionTest.cpp. Specify

#include "outputToMatlb.h"

at top of the program, and change the call at the bottom of the file from


October 1, 2008

Files have been changed in the ArrayClass repository.

To do Assign2, you'll need to download a new version. If you are using hg, then you can just update your files by changing into the ArrayClasses directory and executing the two statements

hg pull
hg update

If you created the repository without cloning it, you'll need to specify the repository address

If you are not using hg, then you'll need to download the zip file, uncompress it, and then replace your existing files.

September 29, 2008

GNUplot commands used in todays' demonstration
There are many commands to become familiar with --- see GNUplot documentation more information and samples. Below I've given the commands that I used during the class demonstration.

The windows version of GNUplot has a rudimentary user interface (selection of the menu items creates the commands for you) while most Linux/Unix installation have a command line interface and you have to type in the commands yourself. Both interfaces, however, remember commands and allow command line editing. You can use the up-arrow key on your keyboard to recall previous commands.

To get a surface plot of the output

splot 'Z:\270eCourseDirectory\Assign1\GNUplotTest2D.dat' w l

To get a color surface, set pm3d and then replot, e.g.

set pm3d

To get a contour plot of the output

set view map
unset surface
set contour

splot 'Z:\270eCourseDirectory\Assign1\GNUplotTest2D.dat' w l

To print the output to a .png file (.png = Portable Network Graphics) that can be viewed by most web browsers.

set term png
set output "GNUplotTestOutput.png"

splot 'Z:\270eCourseDirectory\Assign1\GNUplotTest2D.dat' w l
set term windows

set output