Function Handles

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Misc

Mid-semester Course Evaluations

Random names are stressful.

Is there an alternative that encourages engaged reading with less stress?

Exams

A review sheet and less time pressure would be nice.

I can definitely do a slightly shorter test next time, and the final automatically has more time.

Maybe old test(s) as study guides but not review sheets per se (old tests seem to require more involvement from you).

Post grades on Canvas.

I’ll look into this.

Continue one-on-one grading, labs, extra credit.

Why homework vs lab?

Homework projects involve working a little more independently

Another Programming Course

Look at Math 384, Computational Graphics, for the fall.

Questions?

Why function handles?

Function handles let you have variables whose values are functions

Function Handles

Example: write a function that takes another function, f, and two x values, x1 and x2, as arguments, and that returns the amount by which f changes between x1 and x2 (i.e., f(x2) - f(x1)).

Relevant ideas or questions from reading

• You can have functions as arguments to other functions and define them in calls
• Use @ to define an anonymous function as in @(x) x^2 - 1
• You only need ...(x)... when creating an anonymous function, but, for example @tan creates a handle to existing tan function

Here’s the function we developed

function [ d ] = deltaF( f, x1, x2 )
%DELTAF Find the change in function f between x1 and x2
    d = f(x2) - f(x1);
end

And here are some examples of it in use:

>> deltaF( @tan, 0, 1 )
ans =
    1.5574
>> f = @(x) x^2 - 3
f = 
    @(x)x^2-3
>> deltaF( f, 0, 1 )
ans =
     1
>> deltaF( @(x) x^3 + x, 0, 1 )
ans =
     2

Next

Come up with an example that you can use as a test case for your Newton’s method function, i.e., an instance of Newton’s method finding a root that you can carry out by hand so you know what the result should be, but that you can also use to test the Newton’s method function you’re about to write.

• Such uses of examples kill two birds with one stone: they help you understand a problem, and they give you something to test a programmed solution with. And they might even help you discover an algorithm to use in a program.

Lab time for Newton’s method.

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