EGR 103/Fall 2013/Lab 3

Concepts discussed during explanation of each problem:

• First problem: Van Der Waals Equation
  • Use of strings in MATLAB
    • Numerical values stored for letters
    • Issue with strings of differing lengths
  • strcmp command
  • Use of switch...case statement instead of if tree with strcmp
    • otherwise case
    • multiple triggers with {'trigger1', 'trigger2', ... }
    • Only good for exact matches
  • Plotting using different point styles
• Second problem: Beam Displacement
  • if statements and logic
    • implied all() with logic
  • MATLAB:Logical Masks
    • Be careful about (logic) .* (function) versus logic .* function
      • 2<1*3 yields "true"
    • Never use a<X<b; use a<X & X<b instead
      • a<X\(<\)b yields all 1's if b>1, regardless of a or X values
  • find command
    • Finding non-zeroes
      • find(X)
      • find(A>0)
    • Using indices to determine values
      • X(find(X)), A(find(A>0)), t(find(y==min(y)))
  • Using more points for better answer
  • MATLAB tolerance and dangers of ==
    • min(y)==-1 fails
    • format long e shows why
    • use abs(min(y)-(-1)) < tol instead for some value of tol
  • Speed of displaying versus creating matrices
  • Problems using huge number of points for plot
• Third problem: Pipe
  • Notion that functions can do more than just calculate matrices
• Fourth problem: Leap year
  • Notion of validating inputs
  • Using nargin to check input count along with if tree
  • error command
  • Use of testing function to create diary
• Fifth problem: Rocket
  • Use of anonymous function with logical mask