Gromacs  2025-dev-20240614-602a366
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Groups Pages
List of all members | Public Member Functions | Static Public Member Functions | Static Public Attributes | Protected Attributes
gmx::test::SimdBaseTest Class Reference

#include <gromacs/simd/tests/base.h>

Inherits Test.


Base class for SIMD test fixtures.

This class contains settings that are common for SIMD and SIMD4 tests, and it is thus not used directly for any tests, but derived separately in simd.h and simd4.h.

Public Member Functions

 SimdBaseTest ()
 Initialize new SIMD test fixture with default tolerances. More...
void setUlpTol (std::int64_t newTol)
 Adjust ulp tolerance from the default 10 (float) or 255 (double).
void setUlpTolSingleAccuracy (std::int64_t newTol)
 Adjust ulp tolerance for single accuracy functions.
void setAbsTol (real newTol)
 Adjust the absolute tolerance from the default 0. More...
::testing::AssertionResult compareVectorRealUlp (const char *refExpr, const char *tstExpr, const std::vector< real > &ref, const std::vector< real > &tst) const
 Compare two std::vector<real> for approximate equality. More...
template<typename T >
::testing::AssertionResult compareVectorEq (const char *refExpr, const char *tstExpr, const std::vector< T > &ref, const std::vector< T > &tst)
 Compare std::vectors for exact equality. More...

Static Public Member Functions

static constexpr std::int64_t defaultRealUlpTol ()
 Return the default ulp tolerance for current precision.

Static Public Attributes

static int s_nPoints = 10000
 Number of test points to use, settable on command line. More...

Protected Attributes

std::int64_t ulpTol_
 Current tolerance in units-in-last-position.
real absTol_
 Current absolute tolerance.

Constructor & Destructor Documentation

gmx::test::SimdBaseTest::SimdBaseTest ( )

Initialize new SIMD test fixture with default tolerances.

The default absolute tolerance is set to 0, which means the we always check the ulp tolerance by default (passing the absolute tolerance test would otherwise mean we approve the test instantly).

The default ulp tolerance is set based on the target number of bits requested for single or double precision, depending on what the default Gromacs precision is. We add two bits to avoid tests failing due to corner cases where compiler optimization might cause a slight precision loss e.g. for very small numbers.

Most SIMD math functions actually achieve 2-3 ulp accuracy in single, but by being a bit liberal we only catch real errors rather than doing compiler-standard-compliance debugging.

The range is used by derived classes to test math functions. The default test range will be [1,10], which is intentionally conservative so it works with (inverse) square root, division, exponentials, logarithms, and error functions.

Member Function Documentation

template<typename T >
::testing::AssertionResult gmx::test::SimdBaseTest::compareVectorEq ( const char *  refExpr,
const char *  tstExpr,
const std::vector< T > &  ref,
const std::vector< T > &  tst 

Compare std::vectors for exact equality.

The template in this class makes it usable for testing both SIMD floating-point and integers variables, after conversion to vectors. This is an internal implementation routine that will be used by routines in derived child classes that first convert SIMD or SIMD4 variables to std::vector<real>. Do not call it directly.

This routine is designed according to the Google test specs, so the char strings will describe the arguments to the macro.

The comparison is applied to each element, and it returns true if each element in the vector test variable is within the class tolerances of the corresponding reference elements.

void gmx::test::SimdBaseTest::setAbsTol ( real  newTol)

Adjust the absolute tolerance from the default 0.

If values are closer than the absolute tolerance, the test will pass no matter what their ulp difference is.

The documentation for this class was generated from the following files: