FPChecker (Floating-Point Checker) is a dynamic analysis tool to detect floating-point errors in HPC applications. It is the only tool of its class that supports the most common programming languages and models in HPC, including C/C++, MPI, OpenMP, and CUDA. It is designed to be easy to use and easy to integrate into applications. The tool provides a detailed HTML report that helps users identify the exact location of floating-point errors in the software.
- Easy to use: It only requires a few changes to the application build script, such as changing the compiler (e.g., clang++) by the FPChecker compiler wrappers (e.g., clang++-fpchecker). It automatically instruments the code at build time.
- Accurate detection: It accurately detects errors dynamically (when code is executed) for specific inputs; it doesn’t give alarms for unused or invalid inputs.
- Design for HPC: It supports the most used programming languages and models in HPC: C/C++, MPI, OpenMP, Pthreads, and CUDA.
- Detailed report: It provides a detailed report that programmers can use to identify the exact location (file and line number) of floating-point errors in the software.
Errors and Warnings
FPChecker detects the following floating-point issues:
- Infinity +: Detected when operations produce positive infinity, for example, when 1.0 / 0.0 occurs.
- Infinity -: The same as infinity +, except that the sign of the resulting calculation is negative.
- NaN (not a number): Results from invalid operations, such as 0/0 or sqrt(-1).
- Division by zero: Occurs when a finite nonzero number is divided by zero. This typically produces either infinity or NaN.
- Underflow (subnormal): Detected when an operation produces a subnormal number because the result was not representable as a normal number.
- Comparison: Occurs when two floating-point numbers are compared for equality. Sometimes checking if two floating-point numbers are equal can lead to inaccuracies.
- Cancellation: Occurs when two nearly equal numbers are subtracted. By default, this event is detected when at least ten decimal digits are lost due to a subtraction.
- Latent Infinity +: Detected when an operation produces a large normal and is close to positive infinity.
- Latent Infinity -: Detected when an operation produces a large normal number and is close to negative infinity.
- Latent underflow: Detected when an operation produces a small normal number and is close to becoming an underflow (subnormal number).
For questions, contact Ignacio Laguna at firstname.lastname@example.org.
FPChecker is distributed under the terms of the Apache License (Version 2.0). All new contributions must be made under the Apache-2.0 license. See LICENSE and NOTICE on our FPChecker GitHub for details.