User Tools

Site Tools



This shows you the differences between two versions of the page.

Link to this comparison view

can_t_generate_enough_valid_points_for_comparison [2011/06/19 03:26] (current)
Line 1: Line 1:
 +====== Can't Generate Enough Valid Points for Comparison ====== 
 +Webwork compares functions by plugging in some points and seeing if they match. This error means that Webwork failed when trying to compare the student'​s function/​equation to the correct function/​equation. This occurs when the numbers it tries to plug in to the correct function and the student'​s function are not in the domain of one or both functions. It can also occur due to computational limitations of WeBWorK'​s Perl-based arithmetic engine 
 +  * The calculation involved numbers that were too big. 
 +  * The calculation involved imaginary numbers. 
 +  * The calculation involved non-integer powers of negative numbers. 
 +To fix this, you can explicitly tell Webwork which points to plug in to the functions. Replace, e.g., 
 +fun_cmp("​[correct answer]"​) 
 +fun_cmp("​[correct answer]",​ limits => [a,b] ) 
 +where [a,b] is the interval from which Webwork should pick test points (note that the default test interval for each interval is [-2,2]), or by 
 +fun_cmp("​[correct answer]",​ test_points=>​[a,​b,​c,​d,​e] ) 
 +where a, b, c, d, and e are the specific points which Webwork should test. See [[http://​​wiki/​FormulaTestPoints]] for more details.
can_t_generate_enough_valid_points_for_comparison.txt · Last modified: 2011/06/19 03:26 (external edit)