AlgoTutor Tutorial (4) Using the Virtual Machine Component of AlgoTutor J. Yoo, S. Yoo, C. Pettey, S. Seo, and Z. Dong MTSU Computer Science Department

What is the Virtual Machine? The Virtual Machine is a component of the AlgoTutor System It allows you to visualize the flow of data through an algorithm To use the Virtual Machine, you need to first develop an algorithm for a given problem The Virtual Machine is only available for certain problems

How to use the Virtual Machine Start with an AlgoTutor problem exercise that has been created for the Virtual Machine. Solve the AlgoTutor problem (hint: the ordering and mapping phases are combined into one phase) –Drag Operations into the appropriate order –Click “compare my ordering w/ teacher’s” if you really need help but your grade is penalized if you do this too many times. Also, this only checks the ordering. It does not check the mapping. –Click the variables tab to do the mapping Click “save changes”

How to use the Virtual Machine (continued) Before clicking “Submit for grading” use the Virtual Machine to “trace” the flow of your algorithm –Use drop down arrows to select input –Click Trace execution (if the tracer window doesn’t show up check to see if you need to enable popups) –Click Execute next step to see the result of each step Click “execute w/ selected” to see what would be output by the algorithm with the selected input Click “execute w/ all” to see the grade for your algorithm Click “Submit for grading” when you are happy with your grade

Select a lab

Select an Exercise that has been created for the Virtual Machine

Click the Solve button Notice the operations phase and the mapping phase are merged into one phase

Begin as you would any other AlgoTutor problem by dragging operations from the right to the left.

You can click the Compare my ordering w/ teacher’s button if you need help. But don’t click too many times or it will hurt your grade. Also, only your ordering will be compared. The mapping is not checked.

It does warn you how many free checks you have left before your grade is hurt!!

When you are comfortable with your ordering you can do the mapping and then use the tracer to check the mapping

There is no separate mapping phase. You must click the Variables tab to see the variables

Be sure to click the save changes button before using the virtual machine algorithm tracer

Now you are ready to trace your algorithm. Begin by selecting your input values.

Then click the Trace execution button. If the tracer window doesn’t show up, make sure you have enabled popups.

Click the Execute the next step button to see each step of your algorithm

Values for variables show up here

algorithm output is here

You can also just see what would be output by your algorithm by selecting input and then clicking the Execute w/ selected button

Or you can click the Execute w/ all button to see what your grade would be

Note: Execute All takes a few seconds to complete

Only when you are satisfied should you click the Submit for grading button. You cannot go back and redo anything once that button is clicked

You can change your mind about submitting by clicking Cancel

Click View Solution to see the finished algorithm

Now you can do the next exercise in the lab!!!