Lecture on Relational Questions in MATLAB

Overview of Linear Programming

• Linear programming involves writing code that executes instructions in a sequential order.
• The program executes each instruction one time without skipping or repeating.

Introduction to Relational Questions

• To make programs dynamic, they need to be able to ask questions and make decisions based on the answers.
• This lecture focuses on how to ask relational questions in MATLAB.

Relational Operators

• Relational operators help ask questions about the relationship between two items.
• There are six relational operators:
  • Greater than (>)
  • Greater than or equal to (>=)
  • Less than (<)
  • Less than or equal to (<=)
  • Equal to (==)
  • Not equal to (~=)

Examples of Relational Operators

• Greater than:
  • Example: S1 > 10 where S1 = 10 returns 0 (false).
• Greater than or equal to:
  • Example: S1 >= 10 returns 1 (true).
• Less than:
  • Example: S1 < 33 returns 1 (true).
• Less than or equal to:
  • Example: S1 <= 9 returns 0 (false).
• Not equal to:
  • Denoted by ~=.
  • Example: S1 ~= 10 where S1 = 10 returns 0 (false).
• Equal to:
  • Denoted by == to distinguish from assignment.
  • Example: S1 == 10 returns 1 (true).

Additional Relational Questions

• Relational questions can involve computations and comparisons between variables.
• Examples:
  • S1 > S2 checks if S1 is greater than S2.
  • S1 < S2 - 25 checks if 10 < 5 (returns 0).
  • S1 * 2 > sqrt(13 * S2) evaluates to true as 20 > sqrt(400).

Relational Questions with Vectors

• Example: 2 * S1 < V1 * V2' involves matrix multiplication.
  • Multiplies a row vector by a column vector to produce a scalar.
  • Result: 1 (true).

Conclusion

• Understanding how to use relational operators allows for greater flexibility in programming.
• Next presentation will cover using relational questions with vectors and scalars.