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. 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 References: 16 . * - https://www.python.org/dev/peps/pep-0485/ 17 18 .seealso: `PetscIsCloseAtTolScalar()`, `PetscEqualReal()`, `PetscEqualScalar()` 19 @*/ 20 PetscBool PetscIsCloseAtTol(PetscReal a, PetscReal b, PetscReal rtol, PetscReal atol) 21 { 22 PetscReal diff; 23 /* NaN is not considered close to any other value, including NaN */ 24 if (PetscIsNanReal(a) || PetscIsNanReal(b)) return PETSC_FALSE; 25 /* Fast path for exact equality or two infinities of same sign */ 26 if (a == b) return PETSC_TRUE; 27 /* Handle two infinities of opposite sign */ 28 if (PetscIsInfReal(a) || PetscIsInfReal(b)) return PETSC_FALSE; 29 /* Cannot error if tolerances are negative */ 30 rtol = PetscAbsReal(rtol); 31 atol = PetscAbsReal(atol); 32 /* The regular check for difference within tolerances */ 33 diff = PetscAbsReal(b - a); 34 return ((diff <= PetscAbsReal(rtol * b)) || (diff <= PetscAbsReal(rtol * a)) || (diff <= atol)) ? PETSC_TRUE : PETSC_FALSE; 35 } 36