Description
Wrap a supplied coordinate into a periodic box and return its image index.
Numerical physics calculations depend on discretization, index conventions, boundary conditions and model units. A local force kick is only part of an integration method, a stencil residual is not a solved field, and a one-sided power weight is not a spectral-density normalization. Floating-point resolution also limits grid and coordinate representations.
Wrap a supplied coordinate into a periodic box and return its image index.
When to use this tool
Use Computational Particle Image Wrap Count when you already have coordinate, boxLength and need to wrap a supplied coordinate into a periodic box and return its image index.
How to use the tool and how it works
- Enter coordinate, boxLength. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read imageIndex, wrappedCoordinate. Use the output convention below.
Require boxLength positive/finite; image=floor(coordinate/boxLength), wrapped=coordinate%length adjusted upward if negative.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| coordinate | Coordinate | Required. Finite number. |
| boxLength | Box Length | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| imageIndex | Image Index | Required. Safe integer. |
| wrappedCoordinate | Periodic representative intended in [0,boxLength); floating-point boundary resolution still applies. | Required. Finite number. |
{
"input": {
"coordinate": 12,
"boxLength": 5
},
"output": {
"imageIndex": 2,
"wrappedCoordinate": 2
}
}Limitations and assumptions
- Image index must remain a safe integer. Floating-point endpoints can round; no trajectory, actual cell, boundary interaction or physical periodicity is inferred.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use the complete discretized model, integration algorithm and boundary treatment. Assess convergence, conservation and stability with the full calculation; individual residuals, CFL components, relaxation terms and index mappings do not establish numerical accuracy or physical validity.
References
Similar or alternative tools
- Periodic Ghost Cell Index
Map a supplied storage slot to a periodic interior source index.
- Grid Node Cell Center Offset
Calculate nominal cell-center and node coordinates from a supplied uniform grid.