Hi Jennifer, This is quite a bit of time after your posting, but for anyone else encountering this:
I had this problem because I was trying to test it out in the Studio editor. However, it can only be tested in a live course. See the note at: http://edx.readthedocs.io/projects/edx-partner-course-staff/en/latest/exercises_tools/external_graders.html#external-grader-example To validate your external grader and test a problem, you must view the > component in the LMS, in a published unit. If you attempt to test a problem > in Studio, the message “Error: No grader has been set up for this problem” > displays. > On Wednesday, April 29, 2015 at 8:48:45 PM UTC-4, sandy wrote: > > This is the problem that i have wrote in the blank advance problem in edX: > > <problem title="Embedded Code Box" display_name="" graceperiod="0 day 5 > hours 0 minutes 0 seconds" markdown="null" rerandomize="never" > showanswer="always" start="2013-02-05T00:00" > xqa_key="qaijS3UatK020Wc0sfCtFe0V6jpB4d64"> > <text> > <p> We are searching for > the smallest monthly payment such that we can pay off the > entire balance of a loan within a year.</p> > <p> The following values might be useful when writing your solution</p> > <blockquote> > <p><strong>Monthly interest rate</strong> > = (Annual interest rate) / 12<br/> > <strong>Monthly payment lower bound</strong> > = Balance / 12<br/> > > <strong>Monthly payment upper bound</strong> = (Balance x > (1 + Monthly interest rate)<sup>12</sup>) / 12 > </p> > </blockquote> > <p>The following variables contain values as described below:</p> > <ol> > <li> > <p><code>balance</code> - the outstanding balance on the credit > card</p> > </li> > <li> > <p><code>annualInterestRate</code> - annual interest rate as a > decimal</p> > </li> > </ol> > <p>Write a program that uses these bounds and bisection > search (for more info check out <a href=" > http://en.wikipedia.org/wiki/Bisection_method"; target="_blank">the > Wikipedia page > on bisection search</a>) > to find the smallest monthly payment <em>to the cent</em> > such that we can pay off the > debt within a year.</p> > <p>Note that if you do not use bisection search, your code will not > run - your code only has > 30 seconds to run on our servers. If you get a message that states > "Your submission could not be graded. Please recheck your > submission and try again. If the problem persists, please notify the > course staff.", check to be > sure your code doesn't take too long to run.</p> > <p>The code you paste into the following box should not specify the > values for the variables <code>balance</code> > or <code>annualInterestRate</code> - our test code will define those > values > before testing your submission. </p> > </text> > <coderesponse> > <textbox rows="10" cols="70" mode="python" tabsize="4"/> > <codeparam> > <initial_display/> > <answer_display> > monthlyInterestRate = annualInterestRate/12 > lowerBound = balance/12 > upperBound = (balance * (1+annualInterestRate/12)**12)/12 > originalBalance = balance > > # Keep testing new payment values > # until the balance is +/- $0.02 > while abs(balance) > .02: > # Reset the value of balance to its original value > balance = originalBalance > # Calculate a new monthly payment value from the bounds > payment = (upperBound - lowerBound)/2 + lowerBound > > # Test if this payment value is sufficient to pay off the > # entire balance in 12 months > for month in range(12): > balance -= payment > balance *= 1+monthlyInterestRate > > # Reset bounds based on the final value of balance > if balance > 0: > # If the balance is too big, need higher payment > # so we increase the lower bound > lowerBound = payment > else: > # If the balance is too small, we need a lower > # payment, so we decrease the upper bound > upperBound = payment > > # When the while loop terminates, we know we have > # our answer! > print "Lowest Payment:", round(payment, 2) > </answer_display> > <grader_payload> > {"grader": "ps02/bisect/grade_bisect.py"} > </grader_payload> > </codeparam> > </coderesponse> > <text> > <div> > <b>Note:</b> > <p>Depending on where, and how frequently, you round during > this function, your answers may be off a few cents in > either direction. Try rounding as few times as possible > in order to increase the accuracy of your result. </p> > </div> > <section class="hints"> > <h3>Hints</h3> > <div class="collapsible"> > <header> > <a href="#" id="ht3l">Test Cases to test your code with. Be sure > to test these on your own machine - > and that you get the same output! - before running your code on this > webpage! </a> > </header> > <section id="ht3"> > <p><b>Note:</b> The automated tests are lenient - if your > answers are off by a few cents > in either direction, your code is OK. </p> > <p>Test Cases:</p> > <ol> > <li> > <p> > <pre> > <code> > Test Case 1: > balance = 320000 > annualInterestRate = 0.2 > > Result Your Code Should Generate: > ------------------- > Lowest Payment: 29157.09 > </code> > </pre> > </p> > </li> > <li> > <p> > <pre> > <code> > Test Case 2: > balance = 999999 > annualInterestRate = 0.18 > > Result Your Code Should Generate: > ------------------- > Lowest Payment: 90325.07 > </code> > </pre> > </p> > </li> > </ol> > </section> > </div> > <div class="collapsible"> > <header> > <a href="#" id="ht4">The autograder says, "Your submission could > not be graded." Help!</a> > </header> > <section id="ht4"> > <p> If the autograder gives you the following message:</p> > <pre> > Your submission could not be graded. > Please recheck your submission and try again. If the problem persists, > please notify the course staff. > </pre> > <p>Don't panic! There are a few things that might be wrong with > your code that you should > check out. The number one reason this message appears is because > your code timed out. > You only get 30 seconds of computation time on our servers. If > your code times out, > you probably have an infinite loop. What to do?</p> > <p>The number 1 thing to do is that you need to run this code in > your own local > environment. Your code should print one line at the end of the > loop. If your code never > https://openedx.atlassian.net/browse/TNL-1773prints anything > out - you have an infinite loop!</p> > <p>To debug your infinite loop - check your loop conditional. > When will it stop? > Try inserting print statements inside your loop that prints out > information (like variables) - are you > incrementing or decrementing your loop counter correctly? > Search the forum for people with similar issues. If your search > turns up nothing, > make a new post and paste in your loop conditional for others to > help you out with.</p> > <p>Please don't email the course staff unless your code > legitimately works and prints out the > correct answers in your local environment. In that case, please > email your code file, > a screenshot of the code printing out the correct answers in your > local environment, > and a screenshot of the exact same code not working on the tutor. > The course staff is > otherwise unable to help debug your problem set via email - we can > only address platform issues.</p> > </section> > </div> > </section> > <br/> > </text> > </problem> > > everytime students tried to answer it, then check.. > This error occurs: > Error: No grader has been set up for this problem > -- You received this message because you are subscribed to the Google Groups "General Open edX discussion" group. To view this discussion on the web visit https://groups.google.com/d/msgid/edx-code/a04d7dbd-f143-4ba0-9ba3-a679ad41e7f8%40googlegroups.com.
