\left|\frac{1}{\sqrt{\pi}} \cdot \left(\left(\left(2 \cdot \left|x\right| + \frac{2}{3} \cdot \left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right) + \frac{1}{5} \cdot \left(\left(\left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right) + \frac{1}{21} \cdot \left(\left(\left(\left(\left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right)\right|\left|\frac{1}{\sqrt{\pi}} \cdot \left(\left(\frac{1}{5} \cdot \left(\left|x\right| \cdot \left(\left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right) + \left(\left|x\right| \cdot 2 + \left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \left|x\right|\right) \cdot \frac{2}{3}\right)\right) + \frac{1}{21} \cdot \left(\left|x\right| \cdot \left(\left(\left(\left|x\right| \cdot \left(\left(\left(\left(\left|x\right| \cdot \left|x\right|\right) \cdot \sqrt{\sqrt{\left|x\right|}}\right) \cdot \sqrt{\sqrt{\left|x\right|}}\right) \cdot \sqrt{\left|x\right|}\right)\right) \cdot \left|x\right|\right) \cdot \left|x\right|\right)\right)\right)\right|double f(double x) {
double r2637013 = 1.0;
double r2637014 = atan2(1.0, 0.0);
double r2637015 = sqrt(r2637014);
double r2637016 = r2637013 / r2637015;
double r2637017 = 2.0;
double r2637018 = x;
double r2637019 = fabs(r2637018);
double r2637020 = r2637017 * r2637019;
double r2637021 = 3.0;
double r2637022 = r2637017 / r2637021;
double r2637023 = r2637019 * r2637019;
double r2637024 = r2637023 * r2637019;
double r2637025 = r2637022 * r2637024;
double r2637026 = r2637020 + r2637025;
double r2637027 = 5.0;
double r2637028 = r2637013 / r2637027;
double r2637029 = r2637024 * r2637019;
double r2637030 = r2637029 * r2637019;
double r2637031 = r2637028 * r2637030;
double r2637032 = r2637026 + r2637031;
double r2637033 = 21.0;
double r2637034 = r2637013 / r2637033;
double r2637035 = r2637030 * r2637019;
double r2637036 = r2637035 * r2637019;
double r2637037 = r2637034 * r2637036;
double r2637038 = r2637032 + r2637037;
double r2637039 = r2637016 * r2637038;
double r2637040 = fabs(r2637039);
return r2637040;
}
double f(double x) {
double r2637041 = 1.0;
double r2637042 = atan2(1.0, 0.0);
double r2637043 = sqrt(r2637042);
double r2637044 = r2637041 / r2637043;
double r2637045 = 0.2;
double r2637046 = x;
double r2637047 = fabs(r2637046);
double r2637048 = r2637047 * r2637047;
double r2637049 = r2637048 * r2637047;
double r2637050 = r2637049 * r2637047;
double r2637051 = r2637047 * r2637050;
double r2637052 = r2637045 * r2637051;
double r2637053 = 2.0;
double r2637054 = r2637047 * r2637053;
double r2637055 = 0.6666666666666666;
double r2637056 = r2637049 * r2637055;
double r2637057 = r2637054 + r2637056;
double r2637058 = r2637052 + r2637057;
double r2637059 = 0.047619047619047616;
double r2637060 = sqrt(r2637047);
double r2637061 = sqrt(r2637060);
double r2637062 = r2637048 * r2637061;
double r2637063 = r2637062 * r2637061;
double r2637064 = r2637063 * r2637060;
double r2637065 = r2637047 * r2637064;
double r2637066 = r2637065 * r2637047;
double r2637067 = r2637066 * r2637047;
double r2637068 = r2637047 * r2637067;
double r2637069 = r2637059 * r2637068;
double r2637070 = r2637058 + r2637069;
double r2637071 = r2637044 * r2637070;
double r2637072 = fabs(r2637071);
return r2637072;
}



Bits error versus x
Results
Initial program 0.2
Taylor expanded around -inf 0.2
Simplified0.2
rmApplied add-sqr-sqrt0.2
Applied associate-*r*0.2
rmApplied add-sqr-sqrt0.2
Applied associate-*r*0.2
Final simplification0.2
herbie shell --seed 2019152
(FPCore (x)
:name "Jmat.Real.erfi, branch x less than or equal to 0.5"
(fabs (* (/ 1 (sqrt PI)) (+ (+ (+ (* 2 (fabs x)) (* (/ 2 3) (* (* (fabs x) (fabs x)) (fabs x)))) (* (/ 1 5) (* (* (* (* (fabs x) (fabs x)) (fabs x)) (fabs x)) (fabs x)))) (* (/ 1 21) (* (* (* (* (* (* (fabs x) (fabs x)) (fabs x)) (fabs x)) (fabs x)) (fabs x)) (fabs x)))))))