MATH 493 MATLAB Materials
Week 1
Simple activities
- Basic plotting
- Try also: On the same set of axes, create a plot of y = x, y = sin(x), and y = x^3. Make one graph blue, one red and one green.
- Create a plot of a bell curve, y = e^(-x^2) for x=-4..4. Hint: you'll need the exp function, and to be careful with the powers again.
- Creating matrices in different ways
- Try also: Create a 5x4 matrix; first 2 columns all ones, second two all zeros
- Create a 4x10 matrix; first row 1,2, ..., 10; second row 2, 4, ..., 20; third row 3, 6, ...30; fourth row 4, 8, ..., 40. Use colon notation, not explicit values.
- Syntax for matrix operations
- Try also: Use a search for 'arithmetic operator' to find the difference between x * x, and x .* x, or x^2 and x.^2.
- Which operations (+, -, *, /, ^) have a 'dot' version as well as the 'regular' version?
- Loop structures
- Try also: Write a loop that displays all even numbers from 2 up to 10
- Write a loop that displays numbers counting by 5 from 0 to 100
- Find the sum of all even numbers between 0 and 40 (inclusive), once using a loop, and a second time using sum
More advanced activities
-
Heat equation - PDE solving example
- Download and run the script as-is.
- Change the end-point temperatures.
- Change the initial temperature profile in the beam to be a sine wave (which then cools towards a constant temperature).
- Reduce the time interval between steps to speed up the simulation.
-
Image loading and display
- Download the images zip file and unzip it in your MATLAB directory. You should now have a 'rotated' and 'newtest' subdirectories.
- Download and run the script as-is.
- Change the directory where the script finds the images from
'rotated' to 'newtest'.
- Have the process skip over any file with more than 300 columns of pixels.
- Use the 'imresize' command to resize all images to the same size
before averaging, rather than finding the average only over the
smallest image region.
- Temperature DE - ODE solving example (single variable)
- Download tempScript.m and
tempDE.m
- Look at the code in tempDE.m and relate it to Newton's Law of Heating and Cooling (source DE).
- Run tempScript.m and see the text and graphical output.
- Change the initial temperature -20.
- Change the simulation time interval to t=0..40.
- Increase the cooling coefficient value and see the effect on the model.
- Try to create two plots on the same axes, showing the simulation
for two different cooling coefficient values.
- Spring DE - ODE solving example (2-variable system)
- Download springScript.m and
springDE.m
- Look at the code in springDE.m and compare it to the DE x'' = -k x.
- Run srpingScript.m and see the graphical output.
- Change the initial position and velocity.
- Change the spring coefficient to see the effect on the motion.
- Change the DE so it includes friction: x'' = -kx -cx'. Simulate and see how friction affects the motion.
- Change the DE so that is represents the motion of a pendulum: x'' = -k sin(x). Increase the initial velocity until you see the 'going over the top' behaviour of a pendulum.
- MEX MATLAB-to-C Connection