Difference between revisions of "ConstantsInProblems"
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| − | <h2>Named Constants in Problems: PG Code Snippet</h2> |
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| + | {{historical}} |
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| + | <p style="font-size: 120%;font-weight:bold">This problem has been replaced with [https://openwebwork.github.io/pg-docs/sample-problems/problem-techniques/ConstantsInProblems.html a newer version of this problem]</p> |
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| + | <h2>Named Numerical Constants (Parameters) in Problems: PG Code Snippet</h2> |
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| − | + | Context("Numeric"); |
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| − | + | Context()->constants->add(k=>0.01); |
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| + | # this means that student answers are |
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| + | # not reduced to the numerical value |
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| + | # specified in the Context |
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| + | Context()->flags->set( |
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| + | formatStudentAnswer=>'parsed' |
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| + | ); |
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| − | No changes are needed in the tagging and description or initialization sections of the problem file. In the problem set-up section, we add to the Context the constants we're going to use. Here we define a constant k, and assign it a value that will be used when expressions involving k are evaluated. |
+ | No changes are needed in the tagging and description or initialization sections of the problem file. In the problem set-up section, we add to the Context the constants we're going to use. Here we define a constant k, and assign it a value that will be used when expressions involving k are evaluated. Do not set k=1, because if you do, then kx and x/k are equivalent, for example. Obviously, do not set k=0. |
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In this case we specified <code>constants->add()</code>, so that the constant k is added to existing constants in the problem. If we had used <code>constants->are()</code>, we would also remove all predefined constants from the Context (in a manner similar to the use of <code>variables->add()</code> and <code>variables->are()</code> when [[VariablesOtherThanX|defining variables]] in a problem. |
In this case we specified <code>constants->add()</code>, so that the constant k is added to existing constants in the problem. If we had used <code>constants->are()</code>, we would also remove all predefined constants from the Context (in a manner similar to the use of <code>variables->add()</code> and <code>variables->are()</code> when [[VariablesOtherThanX|defining variables]] in a problem. |
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| + | </p> |
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| + | <p> |
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| + | One other tweak that we might want to put in here is to reset a |
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| + | [[Context_flags|Context flag]] so that students' answers are not reduced to numerical |
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| + | values when they are previewed or submitted. This is done by setting the <code>formatStudentAnswer</code> flag, as shown. |
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| − | + | BEGIN_TEXT |
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| − | + | \(f(x) = x-k\) (where \(k>0\) is constant) |
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| − | + | is zero when $BR |
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| − | + | \(x = \)\{ ans_rule(15) \} |
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| − | + | END_TEXT |
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| − | + | ANS( Compute("k")->cmp() ); |
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[[IndexOfProblemTechniques|Problem Techniques Index]] |
[[IndexOfProblemTechniques|Problem Techniques Index]] |
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| + | [[Category:Problem_Techniques]] |
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Latest revision as of 08:14, 28 June 2023
This problem has been replaced with a newer version of this problem
Named Numerical Constants (Parameters) in Problems: PG Code Snippet
This code snippet shows the essential PG code to include named constants in a WeBWorK problem. Note that these are insertions, not a complete PG file. This code will have to be incorporated into the problem file on which you are working.
| PG problem file | Explanation |
|---|---|
Context("Numeric");
Context()->constants->add(k=>0.01);
# this means that student answers are
# not reduced to the numerical value
# specified in the Context
Context()->flags->set(
formatStudentAnswer=>'parsed'
);
|
No changes are needed in the tagging and description or initialization sections of the problem file. In the problem set-up section, we add to the Context the constants we're going to use. Here we define a constant k, and assign it a value that will be used when expressions involving k are evaluated. Do not set k=1, because if you do, then kx and x/k are equivalent, for example. Obviously, do not set k=0.
In this case we specified
One other tweak that we might want to put in here is to reset a
Context flag so that students' answers are not reduced to numerical
values when they are previewed or submitted. This is done by setting the |
BEGIN_TEXT
\(f(x) = x-k\) (where \(k>0\) is constant)
is zero when $BR
\(x = \)\{ ans_rule(15) \}
END_TEXT
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In the text section of the problem we then ask a question involving the constant. |
ANS( Compute("k")->cmp() );
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And in the answer and solution section of the file we can refer to the constant in the solution to the problem. |
