1: #include <petscsys.h> 3: /*@C 4: PetscIsCloseAtTol - Returns whether the two `PetscReal` numbers 5: are close at a given relative and absolute tolerances. 7: Input Parameters: 8: + a - first floating point number 9: . b - second floating point number 10: . rtol - relative tolerance 11: - atol - absolute tolerances 13: Level: beginner 15: Reference: 16: . * - https://www.python.org/dev/peps/pep-0485/ 18: .seealso: `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: }