Run an Algorithm
The term running an algorithmis used here to mean doing a set of calculations:
What do you need to know to run an algorithm in an examination?
- You need to understand the meanings of all variables to an extent that you are able to assign correct values to them.
- You need to be able to write down the steps in the algorithm.
- You need to be able to run the algorithm.
For example, here's a 'run' of the algorithm for solving for the forces at joint B in the Nodal Analysis key example:
Isolate Joint B | |
---|---|
Apply vertical equilibrium:Substitute for:Rearrange to find an expression for |
Apply horizontal equilbrium:Divide each term by :Substitute :
Solve for : |
The steps in the algorithm are:
- Draw the free body diagram for the joint. The input variables are:
- The 9 kN force in member AB that has been previously calculated
- The 3 kN load on the joint
- The geometry of the joint in terms of the angles between the members
- The output variables are: and
- Resolve the forces into the and Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle y} directions.
- Write the equation of equilibrium for the Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle x} or the Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle y} direction.
- Use the rules of algebra to find an expression for one of the output variables (A) in terms of the other output variable (B).
- Write the equation of equilibrium for the other direction.
- Substitute the expression for variable A and solve for the value of variable B
- Back-substitute to get the value of variable A.
How do you practise so as to be able to do that?
- You could start by working with examples, exercises, definitions and explanations until you have an understanding of the process. Practise using the algorithm.
- Keep asking questions such as ‘What does that mean?’ ‘How do I do that?’
- Then work on your memory. Memory should follow understanding.
- Write down the variables and make sure that you know how to assign values to them.
- Write out the algorithm. Make sure that you can do that from memory and that you know how to perform the steps.
- Do not leave anything to the last minute. Few people can cram for understanding; both memorising facts and developing understanding need repetition.
- That is the process that I used as a student. It got me good marks.