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Modifying a function

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Johann Dirry edited this page May 23, 2026 · 1 revision

Modifying a function

You can modify a function's truth table, logic equation, or gate diagram. When you modify one representation of the function the other two will change to reflect the modification.

To modify the truth table:

  1. Select Truthtable | Modify Truth Table. The variables dialog will appear with current variable names filled in.
  2. Make any desired changes to the variables. You can change any variable name and the number of outputs. You cannot change the number of inputs. The editing procedure is the same as for entering a truth table.
  3. Click OK to close the variable dialog and the truth table will appear for editing with the current output values filled in.
  4. Make any desired changes to the truth table and then select Truthtable | Submit or just press ENTER. To cancel the modification select Truthtable | Cancel or press ESC.

If you change the truth table, a new logic equation will be generated, the gate diagram will be deleted, and the function will be marked unminimized.

To modify the logic equation:

  1. Select Equation | Modify Equation. The equation entry window will appear with the current equation filled in. The current equation is the last result displayed in the equation output window.
  2. Make any desired changes to the equation. You can change anything, including the number of input variables. The editing procedure is the same as for entering a equation.
  3. When you are done editing, select Equation | Submit or just press ENTER. To cancel the modification select Equation | Cancel or press ESC.

If you change the logic equation, a new truth table will be generated, the gate diagram will be deleted, and the function will be marked unminimized.

To modify the gate diagram:

  1. Select Gates | Modify Gate Diagram. The diagram entry window will appear with the current diagram ready for editing.
  2. Make any desired changes to the diagram. You can change anything, including the number of input variables. The editing procedure is the same as for entering a gate diagram.
  3. When you are done editing select Submit in the tool window or press ENTER. To cancel the modification select Cancel in the tool window or press ESC.

If you make substantive changes to the diagram by modifying the logic or variable names a new truth table and logic equation will be generated, and the function will be marked unminimized. Note that a modified diagram might not be an optimal solution. You can generate an optimized diagram for the modified function by mapping it again.

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