TEST_FUNCTION_COUNT

Test if an algorithm operating on a function correctly counts the number of function evaluations.

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Contents

Syntax

TEST_FUNCTION_COUNT(f,g)
TEST_FUNCTION_COUNT(f,g,name,print,color)
output = TEST_FUNCTION_COUNT(__)

Description

TEST_FUNCTION_COUNT(f,g) tests if the function f_fast is faster to evaluate than the function f_slow, where both functions do not have any input arguments. By default, these functions are both evaluated 1000 times in order to compute an average evaluation time.

TEST_FUNCTION_COUNT(f,g,name,print,color) does the same as the syntax above, but also allows the user to specify a test name, whether or not to print the test results to the Command Window, and whether or not to print those test results in color. This syntax is primarily used when defining unit test classes.

outputs = TEST_FUNCTION_COUNT(...) also returns the test outputs. Again, this syntax is primarily used when defining unit test classes.

Inputs

Variable Description Format
f_fast function handle for faster function 1×1
function_handle
f_slow function handle for slower function 1×1
function_handle
args (OPTIONAL) input arguments to functions (defaults to empty cell array) cell array
n_eval (OPTIONAL) number of times to evaluate functions when determining average evaluation time (defaults to 1000) 1×1
double
name (OPTIONAL) test name (defaults to empty string) char array
print (OPTIONAL) true if test result should be printed to Command Window, false otherwise (defaults to true) 1×1
logical
color (OPTIONAL) true if test result should be printed in color, false otherwise (defaults to true) 1×1
logical

NOTE: f_fast and f_slow must have the same input/output behavior.

Outputs

Variable Description Format
output test outputs

Field Description Format
passed true if test passed, false otherwise 1×1
logical
result string storing result of test char array
message string storing additional diagnostic message char array
1×1
struct

Example

Let's define the function $f(x)=x^{2}-1$.

f = @(x) x^2-1;

Now, let's define a function $g(f)$ that takes $f$ as an input and returns the number of times $f$ is evaluated when MATLAB's fzero function is used to find the root of $f(x)$ using an initial interval of $[a,b]=[0,10]$. Note that we use function_for_example at the bottom of this page to help define $g(f)$.

g = @(f) function_for_example(f,0,10);

The fzero function returns the number of function evaluations it performs. To ensure it returns the correct number of function evaluations (i.e. it does not make a mistake in counting), we can use the TEST_FUNCTION_COUNT function.

TEST_FUNCTION_COUNT(f,g);

Function for Example

function n_feval = function_for_example(f,a,b)
    [~,~,~,output] = fzero(f,[a,b]);
    n_feval = output.funcCount;
end

Passed.


Published with MATLAB® R2022a