Boundary check
A boundary check is a test that verifies whether a value or operation lies within an allowed range or valid data extent.
Fast Python: High performance techniques for large datasets
- How it is used
- Uses index guards to prevent invalid array accesses in GPU kernels and to weigh safety against speed in Cython.
- How deep it goes
- Explains the risk of unchecked indexing and demonstrates an extent guard, while deferring broader bounds-checking and NumPy optimizations.
- Examples
- Demonstrates guarding a 1,000-element array against 1,008 GPU thread positions and disabling checks for Cython image processing.
- What you can do after
- Apply explicit extent guards to keep excess GPU threads from accessing array positions beyond the valid range.
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100 Java Mistakes and How to Avoid Them
A bounds check is a validation that an index or indexed range lies within the permitted limits of a data structure.
- How it is used
- Prevents invalid array, string, list, and indexed-range access before it causes exceptions or worse program behavior.
- How deep it goes
- Explains empty inputs, ordering errors, reversed comparisons, off-by-one errors, range constraints, and standard library checks.
- Examples
- Uses empty strings, array element access, offset-count ranges, and custom InputStream and List implementations.
- What you can do after
- Diagnose/debug with it by locating unsafe access order, reversed comparisons, and off-by-one conditions.
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Related concepts
- out-of-bounds array accessaddresses · An out-of-bounds array access is an operation that reads or writes an element or memory location outside the valid range of an array or associated object.
- GPU kernelused by · A GPU kernel is an executable program or function that performs computation on a graphics processing unit, commonly using parallel threads.
- strideuses · A stride is the step interval between successive positions or elements accessed, selected, or processed along a dimension or sequence.
- indexingused by · Indexing is the organization or use of positions, keys, or lookup structures to identify and retrieve selected data or elements.
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