Practice question · Sort into groups
Sort each claim by whether the computation described actually justifies it.
Groups: Justified · Not justified
- The output numbers look plausible
- Total energy stays constant to within round-off across the run
- The simulation ran without errors, so the answer is right
- The scheme reproduces the known analytic solution to five digits
- Halving the grid changes the answer by less than the required tolerance
Hints
- A genuine check compares the output against something independently known.
- Plausibility and the absence of crashes are not comparisons with anything.
Show the answer
Justified: The scheme reproduces the known analytic solution to five digits, Total energy stays constant to within round-off across the run, Halving the grid changes the answer by less than the required tolerance
Not justified: The simulation ran without errors, so the answer is right, The output numbers look plausible
Why
Agreement with an exact solution, conservation of a known invariant, and grid convergence are all real evidence. Running without errors and looking plausible test nothing, a confident wrong answer passes both.
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