1 #include <petscsys.h> 2 3 /*@C 4 PetscIsCloseAtTol - Returns whether the two `PetscReal` numbers 5 are close at a given relative and absolute tolerances <https://www.python.org/dev/peps/pep-0485/>. 6 7 Input Parameters: 8 + a - first floating point number 9 . b - second floating point number 10 . rtol - relative tolerance 11 - atol - absolute tolerances 12 13 Level: beginner 14 15 .seealso: `PetscIsCloseAtTolScalar()`, `PetscEqualReal()`, `PetscEqualScalar()` 16 @*/ 17 PetscBool PetscIsCloseAtTol(PetscReal a, PetscReal b, PetscReal rtol, PetscReal atol) 18 { 19 PetscReal diff; 20 /* NaN is not considered close to any other value, including NaN */ 21 if (PetscIsNanReal(a) || PetscIsNanReal(b)) return PETSC_FALSE; 22 /* Fast path for exact equality or two infinities of same sign */ 23 if (a == b) return PETSC_TRUE; 24 /* Handle two infinities of opposite sign */ 25 if (PetscIsInfReal(a) || PetscIsInfReal(b)) return PETSC_FALSE; 26 /* Cannot error if tolerances are negative */ 27 rtol = PetscAbsReal(rtol); 28 atol = PetscAbsReal(atol); 29 /* The regular check for difference within tolerances */ 30 diff = PetscAbsReal(b - a); 31 return ((diff <= PetscAbsReal(rtol * b)) || (diff <= PetscAbsReal(rtol * a)) || (diff <= atol)) ? PETSC_TRUE : PETSC_FALSE; 32 } 33