Compound Interest

Percentage Accurate: 27.7% → 94.6%
Time: 15.1s
Alternatives: 13
Speedup: 12.2×

Specification

?
\[\begin{array}{l} \\ 100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}} \end{array} \]
(FPCore (i n)
 :precision binary64
 (* 100.0 (/ (- (pow (+ 1.0 (/ i n)) n) 1.0) (/ i n))))
double code(double i, double n) {
	return 100.0 * ((pow((1.0 + (i / n)), n) - 1.0) / (i / n));
}
real(8) function code(i, n)
    real(8), intent (in) :: i
    real(8), intent (in) :: n
    code = 100.0d0 * ((((1.0d0 + (i / n)) ** n) - 1.0d0) / (i / n))
end function
public static double code(double i, double n) {
	return 100.0 * ((Math.pow((1.0 + (i / n)), n) - 1.0) / (i / n));
}
def code(i, n):
	return 100.0 * ((math.pow((1.0 + (i / n)), n) - 1.0) / (i / n))
function code(i, n)
	return Float64(100.0 * Float64(Float64((Float64(1.0 + Float64(i / n)) ^ n) - 1.0) / Float64(i / n)))
end
function tmp = code(i, n)
	tmp = 100.0 * ((((1.0 + (i / n)) ^ n) - 1.0) / (i / n));
end
code[i_, n_] := N[(100.0 * N[(N[(N[Power[N[(1.0 + N[(i / n), $MachinePrecision]), $MachinePrecision], n], $MachinePrecision] - 1.0), $MachinePrecision] / N[(i / n), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 13 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 27.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}} \end{array} \]
(FPCore (i n)
 :precision binary64
 (* 100.0 (/ (- (pow (+ 1.0 (/ i n)) n) 1.0) (/ i n))))
double code(double i, double n) {
	return 100.0 * ((pow((1.0 + (i / n)), n) - 1.0) / (i / n));
}
real(8) function code(i, n)
    real(8), intent (in) :: i
    real(8), intent (in) :: n
    code = 100.0d0 * ((((1.0d0 + (i / n)) ** n) - 1.0d0) / (i / n))
end function
public static double code(double i, double n) {
	return 100.0 * ((Math.pow((1.0 + (i / n)), n) - 1.0) / (i / n));
}
def code(i, n):
	return 100.0 * ((math.pow((1.0 + (i / n)), n) - 1.0) / (i / n))
function code(i, n)
	return Float64(100.0 * Float64(Float64((Float64(1.0 + Float64(i / n)) ^ n) - 1.0) / Float64(i / n)))
end
function tmp = code(i, n)
	tmp = 100.0 * ((((1.0 + (i / n)) ^ n) - 1.0) / (i / n));
end
code[i_, n_] := N[(100.0 * N[(N[(N[Power[N[(1.0 + N[(i / n), $MachinePrecision]), $MachinePrecision], n], $MachinePrecision] - 1.0), $MachinePrecision] / N[(i / n), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}}
\end{array}

Alternative 1: 94.6% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := {\left(1 + \frac{i}{n}\right)}^{n}\\ t_1 := \frac{t\_0 + -1}{\frac{i}{n}}\\ \mathbf{if}\;t\_1 \leq 2 \cdot 10^{-215}:\\ \;\;\;\;100 \cdot \frac{\mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)}{\frac{i}{n}}\\ \mathbf{elif}\;t\_1 \leq \infty:\\ \;\;\;\;\frac{n \cdot \mathsf{fma}\left(t\_0, 100, -100\right)}{i}\\ \mathbf{else}:\\ \;\;\;\;n \cdot 100\\ \end{array} \end{array} \]
(FPCore (i n)
 :precision binary64
 (let* ((t_0 (pow (+ 1.0 (/ i n)) n)) (t_1 (/ (+ t_0 -1.0) (/ i n))))
   (if (<= t_1 2e-215)
     (* 100.0 (/ (expm1 (* n (log1p (/ i n)))) (/ i n)))
     (if (<= t_1 INFINITY) (/ (* n (fma t_0 100.0 -100.0)) i) (* n 100.0)))))
double code(double i, double n) {
	double t_0 = pow((1.0 + (i / n)), n);
	double t_1 = (t_0 + -1.0) / (i / n);
	double tmp;
	if (t_1 <= 2e-215) {
		tmp = 100.0 * (expm1((n * log1p((i / n)))) / (i / n));
	} else if (t_1 <= ((double) INFINITY)) {
		tmp = (n * fma(t_0, 100.0, -100.0)) / i;
	} else {
		tmp = n * 100.0;
	}
	return tmp;
}
function code(i, n)
	t_0 = Float64(1.0 + Float64(i / n)) ^ n
	t_1 = Float64(Float64(t_0 + -1.0) / Float64(i / n))
	tmp = 0.0
	if (t_1 <= 2e-215)
		tmp = Float64(100.0 * Float64(expm1(Float64(n * log1p(Float64(i / n)))) / Float64(i / n)));
	elseif (t_1 <= Inf)
		tmp = Float64(Float64(n * fma(t_0, 100.0, -100.0)) / i);
	else
		tmp = Float64(n * 100.0);
	end
	return tmp
end
code[i_, n_] := Block[{t$95$0 = N[Power[N[(1.0 + N[(i / n), $MachinePrecision]), $MachinePrecision], n], $MachinePrecision]}, Block[{t$95$1 = N[(N[(t$95$0 + -1.0), $MachinePrecision] / N[(i / n), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$1, 2e-215], N[(100.0 * N[(N[(Exp[N[(n * N[Log[1 + N[(i / n), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]] - 1), $MachinePrecision] / N[(i / n), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$1, Infinity], N[(N[(n * N[(t$95$0 * 100.0 + -100.0), $MachinePrecision]), $MachinePrecision] / i), $MachinePrecision], N[(n * 100.0), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := {\left(1 + \frac{i}{n}\right)}^{n}\\
t_1 := \frac{t\_0 + -1}{\frac{i}{n}}\\
\mathbf{if}\;t\_1 \leq 2 \cdot 10^{-215}:\\
\;\;\;\;100 \cdot \frac{\mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)}{\frac{i}{n}}\\

\mathbf{elif}\;t\_1 \leq \infty:\\
\;\;\;\;\frac{n \cdot \mathsf{fma}\left(t\_0, 100, -100\right)}{i}\\

\mathbf{else}:\\
\;\;\;\;n \cdot 100\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (/.f64 (-.f64 (pow.f64 (+.f64 #s(literal 1 binary64) (/.f64 i n)) n) #s(literal 1 binary64)) (/.f64 i n)) < 2.00000000000000008e-215

    1. Initial program 21.9%

      \[100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto 100 \cdot \frac{{\left(1 + \color{blue}{\frac{i}{n}}\right)}^{n} - 1}{\frac{i}{n}} \]
      2. lift-+.f64N/A

        \[\leadsto 100 \cdot \frac{{\color{blue}{\left(1 + \frac{i}{n}\right)}}^{n} - 1}{\frac{i}{n}} \]
      3. pow-to-expN/A

        \[\leadsto 100 \cdot \frac{\color{blue}{e^{\log \left(1 + \frac{i}{n}\right) \cdot n}} - 1}{\frac{i}{n}} \]
      4. lower-expm1.f64N/A

        \[\leadsto 100 \cdot \frac{\color{blue}{\mathsf{expm1}\left(\log \left(1 + \frac{i}{n}\right) \cdot n\right)}}{\frac{i}{n}} \]
      5. *-commutativeN/A

        \[\leadsto 100 \cdot \frac{\mathsf{expm1}\left(\color{blue}{n \cdot \log \left(1 + \frac{i}{n}\right)}\right)}{\frac{i}{n}} \]
      6. lower-*.f64N/A

        \[\leadsto 100 \cdot \frac{\mathsf{expm1}\left(\color{blue}{n \cdot \log \left(1 + \frac{i}{n}\right)}\right)}{\frac{i}{n}} \]
      7. lift-+.f64N/A

        \[\leadsto 100 \cdot \frac{\mathsf{expm1}\left(n \cdot \log \color{blue}{\left(1 + \frac{i}{n}\right)}\right)}{\frac{i}{n}} \]
      8. lower-log1p.f6499.1

        \[\leadsto 100 \cdot \frac{\mathsf{expm1}\left(n \cdot \color{blue}{\mathsf{log1p}\left(\frac{i}{n}\right)}\right)}{\frac{i}{n}} \]
    4. Applied egg-rr99.1%

      \[\leadsto 100 \cdot \frac{\color{blue}{\mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)}}{\frac{i}{n}} \]

    if 2.00000000000000008e-215 < (/.f64 (-.f64 (pow.f64 (+.f64 #s(literal 1 binary64) (/.f64 i n)) n) #s(literal 1 binary64)) (/.f64 i n)) < +inf.0

    1. Initial program 99.8%

      \[100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto 100 \cdot \frac{{\left(1 + \color{blue}{\frac{i}{n}}\right)}^{n} - 1}{\frac{i}{n}} \]
      2. lift-+.f64N/A

        \[\leadsto 100 \cdot \frac{{\color{blue}{\left(1 + \frac{i}{n}\right)}}^{n} - 1}{\frac{i}{n}} \]
      3. lift-pow.f64N/A

        \[\leadsto 100 \cdot \frac{\color{blue}{{\left(1 + \frac{i}{n}\right)}^{n}} - 1}{\frac{i}{n}} \]
      4. lift--.f64N/A

        \[\leadsto 100 \cdot \frac{\color{blue}{{\left(1 + \frac{i}{n}\right)}^{n} - 1}}{\frac{i}{n}} \]
      5. *-rgt-identityN/A

        \[\leadsto 100 \cdot \frac{\color{blue}{\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot 1}}{\frac{i}{n}} \]
      6. lift-/.f64N/A

        \[\leadsto 100 \cdot \frac{\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot 1}{\color{blue}{\frac{i}{n}}} \]
      7. associate-*r/N/A

        \[\leadsto 100 \cdot \color{blue}{\left(\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot \frac{1}{\frac{i}{n}}\right)} \]
      8. lift-/.f64N/A

        \[\leadsto 100 \cdot \left(\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot \frac{1}{\color{blue}{\frac{i}{n}}}\right) \]
      9. clear-numN/A

        \[\leadsto 100 \cdot \left(\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot \color{blue}{\frac{n}{i}}\right) \]
      10. associate-*r*N/A

        \[\leadsto \color{blue}{\left(100 \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right)\right) \cdot \frac{n}{i}} \]
      11. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\left(100 \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right)\right) \cdot n}{i}} \]
      12. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\left(100 \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right)\right) \cdot n}{i}} \]
    4. Applied egg-rr99.8%

      \[\leadsto \color{blue}{\frac{\mathsf{fma}\left({\left(1 + \frac{i}{n}\right)}^{n}, 100, -100\right) \cdot n}{i}} \]

    if +inf.0 < (/.f64 (-.f64 (pow.f64 (+.f64 #s(literal 1 binary64) (/.f64 i n)) n) #s(literal 1 binary64)) (/.f64 i n))

    1. Initial program 0.0%

      \[100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}} \]
    2. Add Preprocessing
    3. Taylor expanded in i around 0

      \[\leadsto \color{blue}{100 \cdot n} \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{n \cdot 100} \]
      2. lower-*.f6480.2

        \[\leadsto \color{blue}{n \cdot 100} \]
    5. Simplified80.2%

      \[\leadsto \color{blue}{n \cdot 100} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification95.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{{\left(1 + \frac{i}{n}\right)}^{n} + -1}{\frac{i}{n}} \leq 2 \cdot 10^{-215}:\\ \;\;\;\;100 \cdot \frac{\mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)}{\frac{i}{n}}\\ \mathbf{elif}\;\frac{{\left(1 + \frac{i}{n}\right)}^{n} + -1}{\frac{i}{n}} \leq \infty:\\ \;\;\;\;\frac{n \cdot \mathsf{fma}\left({\left(1 + \frac{i}{n}\right)}^{n}, 100, -100\right)}{i}\\ \mathbf{else}:\\ \;\;\;\;n \cdot 100\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 85.4% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{100}{i} \cdot \left(n \cdot \mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)\right)\\ \mathbf{if}\;i \leq -6 \cdot 10^{-95}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;i \leq 2.8 \cdot 10^{-155}:\\ \;\;\;\;100 \cdot \left(n \cdot \left(\mathsf{fma}\left(i, \mathsf{fma}\left(i, 0.16666666666666666, 0.5\right), 1\right) + \frac{\frac{\left(i \cdot i\right) \cdot 0.3333333333333333}{n} - i \cdot \mathsf{fma}\left(i, 0.5, 0.5\right)}{n}\right)\right)\\ \mathbf{elif}\;i \leq 3.1 \cdot 10^{+117}:\\ \;\;\;\;t\_0\\ \mathbf{else}:\\ \;\;\;\;100 \cdot \mathsf{fma}\left(\frac{1}{i}, n \cdot {\left(\frac{i}{n}\right)}^{n}, \frac{n}{-i}\right)\\ \end{array} \end{array} \]
(FPCore (i n)
 :precision binary64
 (let* ((t_0 (* (/ 100.0 i) (* n (expm1 (* n (log1p (/ i n))))))))
   (if (<= i -6e-95)
     t_0
     (if (<= i 2.8e-155)
       (*
        100.0
        (*
         n
         (+
          (fma i (fma i 0.16666666666666666 0.5) 1.0)
          (/
           (- (/ (* (* i i) 0.3333333333333333) n) (* i (fma i 0.5 0.5)))
           n))))
       (if (<= i 3.1e+117)
         t_0
         (* 100.0 (fma (/ 1.0 i) (* n (pow (/ i n) n)) (/ n (- i)))))))))
double code(double i, double n) {
	double t_0 = (100.0 / i) * (n * expm1((n * log1p((i / n)))));
	double tmp;
	if (i <= -6e-95) {
		tmp = t_0;
	} else if (i <= 2.8e-155) {
		tmp = 100.0 * (n * (fma(i, fma(i, 0.16666666666666666, 0.5), 1.0) + (((((i * i) * 0.3333333333333333) / n) - (i * fma(i, 0.5, 0.5))) / n)));
	} else if (i <= 3.1e+117) {
		tmp = t_0;
	} else {
		tmp = 100.0 * fma((1.0 / i), (n * pow((i / n), n)), (n / -i));
	}
	return tmp;
}
function code(i, n)
	t_0 = Float64(Float64(100.0 / i) * Float64(n * expm1(Float64(n * log1p(Float64(i / n))))))
	tmp = 0.0
	if (i <= -6e-95)
		tmp = t_0;
	elseif (i <= 2.8e-155)
		tmp = Float64(100.0 * Float64(n * Float64(fma(i, fma(i, 0.16666666666666666, 0.5), 1.0) + Float64(Float64(Float64(Float64(Float64(i * i) * 0.3333333333333333) / n) - Float64(i * fma(i, 0.5, 0.5))) / n))));
	elseif (i <= 3.1e+117)
		tmp = t_0;
	else
		tmp = Float64(100.0 * fma(Float64(1.0 / i), Float64(n * (Float64(i / n) ^ n)), Float64(n / Float64(-i))));
	end
	return tmp
end
code[i_, n_] := Block[{t$95$0 = N[(N[(100.0 / i), $MachinePrecision] * N[(n * N[(Exp[N[(n * N[Log[1 + N[(i / n), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]] - 1), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[i, -6e-95], t$95$0, If[LessEqual[i, 2.8e-155], N[(100.0 * N[(n * N[(N[(i * N[(i * 0.16666666666666666 + 0.5), $MachinePrecision] + 1.0), $MachinePrecision] + N[(N[(N[(N[(N[(i * i), $MachinePrecision] * 0.3333333333333333), $MachinePrecision] / n), $MachinePrecision] - N[(i * N[(i * 0.5 + 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / n), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[i, 3.1e+117], t$95$0, N[(100.0 * N[(N[(1.0 / i), $MachinePrecision] * N[(n * N[Power[N[(i / n), $MachinePrecision], n], $MachinePrecision]), $MachinePrecision] + N[(n / (-i)), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{100}{i} \cdot \left(n \cdot \mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)\right)\\
\mathbf{if}\;i \leq -6 \cdot 10^{-95}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;i \leq 2.8 \cdot 10^{-155}:\\
\;\;\;\;100 \cdot \left(n \cdot \left(\mathsf{fma}\left(i, \mathsf{fma}\left(i, 0.16666666666666666, 0.5\right), 1\right) + \frac{\frac{\left(i \cdot i\right) \cdot 0.3333333333333333}{n} - i \cdot \mathsf{fma}\left(i, 0.5, 0.5\right)}{n}\right)\right)\\

\mathbf{elif}\;i \leq 3.1 \cdot 10^{+117}:\\
\;\;\;\;t\_0\\

\mathbf{else}:\\
\;\;\;\;100 \cdot \mathsf{fma}\left(\frac{1}{i}, n \cdot {\left(\frac{i}{n}\right)}^{n}, \frac{n}{-i}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if i < -6e-95 or 2.8e-155 < i < 3.09999999999999975e117

    1. Initial program 35.5%

      \[100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto 100 \cdot \frac{{\left(1 + \color{blue}{\frac{i}{n}}\right)}^{n} - 1}{\frac{i}{n}} \]
      2. lift-+.f64N/A

        \[\leadsto 100 \cdot \frac{{\color{blue}{\left(1 + \frac{i}{n}\right)}}^{n} - 1}{\frac{i}{n}} \]
      3. lift-pow.f64N/A

        \[\leadsto 100 \cdot \frac{\color{blue}{{\left(1 + \frac{i}{n}\right)}^{n}} - 1}{\frac{i}{n}} \]
      4. lift--.f64N/A

        \[\leadsto 100 \cdot \frac{\color{blue}{{\left(1 + \frac{i}{n}\right)}^{n} - 1}}{\frac{i}{n}} \]
      5. *-rgt-identityN/A

        \[\leadsto 100 \cdot \frac{\color{blue}{\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot 1}}{\frac{i}{n}} \]
      6. lift-/.f64N/A

        \[\leadsto 100 \cdot \frac{\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot 1}{\color{blue}{\frac{i}{n}}} \]
      7. associate-*r/N/A

        \[\leadsto 100 \cdot \color{blue}{\left(\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot \frac{1}{\frac{i}{n}}\right)} \]
      8. div-invN/A

        \[\leadsto 100 \cdot \color{blue}{\frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}}} \]
      9. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{100 \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right)}{\frac{i}{n}}} \]
      10. lift-/.f64N/A

        \[\leadsto \frac{100 \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right)}{\color{blue}{\frac{i}{n}}} \]
      11. div-invN/A

        \[\leadsto \frac{100 \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right)}{\color{blue}{i \cdot \frac{1}{n}}} \]
      12. times-fracN/A

        \[\leadsto \color{blue}{\frac{100}{i} \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{1}{n}}} \]
      13. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{100}{i} \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{1}{n}}} \]
      14. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{100}{i}} \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{1}{n}} \]
      15. div-invN/A

        \[\leadsto \frac{100}{i} \cdot \color{blue}{\left(\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot \frac{1}{\frac{1}{n}}\right)} \]
      16. clear-numN/A

        \[\leadsto \frac{100}{i} \cdot \left(\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot \color{blue}{\frac{n}{1}}\right) \]
      17. /-rgt-identityN/A

        \[\leadsto \frac{100}{i} \cdot \left(\left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right) \cdot \color{blue}{n}\right) \]
      18. *-commutativeN/A

        \[\leadsto \frac{100}{i} \cdot \color{blue}{\left(n \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right)\right)} \]
      19. lower-*.f6435.2

        \[\leadsto \frac{100}{i} \cdot \color{blue}{\left(n \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} - 1\right)\right)} \]
    4. Applied egg-rr35.2%

      \[\leadsto \color{blue}{\frac{100}{i} \cdot \left(n \cdot \left({\left(1 + \frac{i}{n}\right)}^{n} + -1\right)\right)} \]
    5. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \left({\left(1 + \color{blue}{\frac{i}{n}}\right)}^{n} + -1\right)\right) \]
      2. lift-+.f64N/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \left({\color{blue}{\left(1 + \frac{i}{n}\right)}}^{n} + -1\right)\right) \]
      3. pow-to-expN/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \left(\color{blue}{e^{\log \left(1 + \frac{i}{n}\right) \cdot n}} + -1\right)\right) \]
      4. lift-+.f64N/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \left(e^{\log \color{blue}{\left(1 + \frac{i}{n}\right)} \cdot n} + -1\right)\right) \]
      5. lift-log1p.f64N/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \left(e^{\color{blue}{\mathsf{log1p}\left(\frac{i}{n}\right)} \cdot n} + -1\right)\right) \]
      6. *-commutativeN/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \left(e^{\color{blue}{n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)}} + -1\right)\right) \]
      7. lift-*.f64N/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \left(e^{\color{blue}{n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)}} + -1\right)\right) \]
      8. metadata-evalN/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \left(e^{n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)} + \color{blue}{\left(\mathsf{neg}\left(1\right)\right)}\right)\right) \]
      9. sub-negN/A

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \color{blue}{\left(e^{n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)} - 1\right)}\right) \]
      10. lift-expm1.f6488.6

        \[\leadsto \frac{100}{i} \cdot \left(n \cdot \color{blue}{\mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)}\right) \]
    6. Applied egg-rr88.6%

      \[\leadsto \frac{100}{i} \cdot \left(n \cdot \color{blue}{\mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)}\right) \]

    if -6e-95 < i < 2.8e-155

    1. Initial program 5.6%

      \[100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}} \]
    2. Add Preprocessing
    3. Taylor expanded in i around 0

      \[\leadsto 100 \cdot \frac{\color{blue}{\left(1 + i \cdot \left(1 + i \cdot \left(\left(\frac{1}{2} + i \cdot \left(\left(\frac{1}{6} + \frac{1}{3} \cdot \frac{1}{{n}^{2}}\right) - \frac{1}{2} \cdot \frac{1}{n}\right)\right) - \frac{1}{2} \cdot \frac{1}{n}\right)\right)\right)} - 1}{\frac{i}{n}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto 100 \cdot \frac{\color{blue}{\left(i \cdot \left(1 + i \cdot \left(\left(\frac{1}{2} + i \cdot \left(\left(\frac{1}{6} + \frac{1}{3} \cdot \frac{1}{{n}^{2}}\right) - \frac{1}{2} \cdot \frac{1}{n}\right)\right) - \frac{1}{2} \cdot \frac{1}{n}\right)\right) + 1\right)} - 1}{\frac{i}{n}} \]
      2. lower-fma.f64N/A

        \[\leadsto 100 \cdot \frac{\color{blue}{\mathsf{fma}\left(i, 1 + i \cdot \left(\left(\frac{1}{2} + i \cdot \left(\left(\frac{1}{6} + \frac{1}{3} \cdot \frac{1}{{n}^{2}}\right) - \frac{1}{2} \cdot \frac{1}{n}\right)\right) - \frac{1}{2} \cdot \frac{1}{n}\right), 1\right)} - 1}{\frac{i}{n}} \]
    5. Simplified1.9%

      \[\leadsto 100 \cdot \frac{\color{blue}{\mathsf{fma}\left(i, \mathsf{fma}\left(i, \mathsf{fma}\left(i, \frac{0.3333333333333333}{n \cdot n} + \left(0.16666666666666666 + \frac{-0.5}{n}\right), 0.5 - \frac{0.5}{n}\right), 1\right), 1\right)} - 1}{\frac{i}{n}} \]
    6. Taylor expanded in n around -inf

      \[\leadsto 100 \cdot \color{blue}{\left(-1 \cdot \left(n \cdot \left(-1 \cdot \left(1 + i \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot i\right)\right) + -1 \cdot \frac{-1 \cdot \left(i \cdot \left(\frac{1}{2} + \frac{1}{2} \cdot i\right)\right) + \frac{1}{3} \cdot \frac{{i}^{2}}{n}}{n}\right)\right)\right)} \]
    7. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto 100 \cdot \color{blue}{\left(\mathsf{neg}\left(n \cdot \left(-1 \cdot \left(1 + i \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot i\right)\right) + -1 \cdot \frac{-1 \cdot \left(i \cdot \left(\frac{1}{2} + \frac{1}{2} \cdot i\right)\right) + \frac{1}{3} \cdot \frac{{i}^{2}}{n}}{n}\right)\right)\right)} \]
      2. *-commutativeN/A

        \[\leadsto 100 \cdot \left(\mathsf{neg}\left(\color{blue}{\left(-1 \cdot \left(1 + i \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot i\right)\right) + -1 \cdot \frac{-1 \cdot \left(i \cdot \left(\frac{1}{2} + \frac{1}{2} \cdot i\right)\right) + \frac{1}{3} \cdot \frac{{i}^{2}}{n}}{n}\right) \cdot n}\right)\right) \]
      3. distribute-rgt-neg-inN/A

        \[\leadsto 100 \cdot \color{blue}{\left(\left(-1 \cdot \left(1 + i \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot i\right)\right) + -1 \cdot \frac{-1 \cdot \left(i \cdot \left(\frac{1}{2} + \frac{1}{2} \cdot i\right)\right) + \frac{1}{3} \cdot \frac{{i}^{2}}{n}}{n}\right) \cdot \left(\mathsf{neg}\left(n\right)\right)\right)} \]
      4. mul-1-negN/A

        \[\leadsto 100 \cdot \left(\left(-1 \cdot \left(1 + i \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot i\right)\right) + -1 \cdot \frac{-1 \cdot \left(i \cdot \left(\frac{1}{2} + \frac{1}{2} \cdot i\right)\right) + \frac{1}{3} \cdot \frac{{i}^{2}}{n}}{n}\right) \cdot \color{blue}{\left(-1 \cdot n\right)}\right) \]
      5. lower-*.f64N/A

        \[\leadsto 100 \cdot \color{blue}{\left(\left(-1 \cdot \left(1 + i \cdot \left(\frac{1}{2} + \frac{1}{6} \cdot i\right)\right) + -1 \cdot \frac{-1 \cdot \left(i \cdot \left(\frac{1}{2} + \frac{1}{2} \cdot i\right)\right) + \frac{1}{3} \cdot \frac{{i}^{2}}{n}}{n}\right) \cdot \left(-1 \cdot n\right)\right)} \]
    8. Simplified92.0%

      \[\leadsto 100 \cdot \color{blue}{\left(\left(\frac{\frac{\left(i \cdot i\right) \cdot 0.3333333333333333}{n} - i \cdot \mathsf{fma}\left(i, 0.5, 0.5\right)}{-n} - \mathsf{fma}\left(i, \mathsf{fma}\left(i, 0.16666666666666666, 0.5\right), 1\right)\right) \cdot \left(-n\right)\right)} \]

    if 3.09999999999999975e117 < i

    1. Initial program 54.4%

      \[100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto 100 \cdot \frac{{\left(1 + \color{blue}{\frac{i}{n}}\right)}^{n} - 1}{\frac{i}{n}} \]
      2. lift-+.f64N/A

        \[\leadsto 100 \cdot \frac{{\color{blue}{\left(1 + \frac{i}{n}\right)}}^{n} - 1}{\frac{i}{n}} \]
      3. pow-to-expN/A

        \[\leadsto 100 \cdot \frac{\color{blue}{e^{\log \left(1 + \frac{i}{n}\right) \cdot n}} - 1}{\frac{i}{n}} \]
      4. lower-expm1.f64N/A

        \[\leadsto 100 \cdot \frac{\color{blue}{\mathsf{expm1}\left(\log \left(1 + \frac{i}{n}\right) \cdot n\right)}}{\frac{i}{n}} \]
      5. *-commutativeN/A

        \[\leadsto 100 \cdot \frac{\mathsf{expm1}\left(\color{blue}{n \cdot \log \left(1 + \frac{i}{n}\right)}\right)}{\frac{i}{n}} \]
      6. lower-*.f64N/A

        \[\leadsto 100 \cdot \frac{\mathsf{expm1}\left(\color{blue}{n \cdot \log \left(1 + \frac{i}{n}\right)}\right)}{\frac{i}{n}} \]
      7. lift-+.f64N/A

        \[\leadsto 100 \cdot \frac{\mathsf{expm1}\left(n \cdot \log \color{blue}{\left(1 + \frac{i}{n}\right)}\right)}{\frac{i}{n}} \]
      8. lower-log1p.f6456.5

        \[\leadsto 100 \cdot \frac{\mathsf{expm1}\left(n \cdot \color{blue}{\mathsf{log1p}\left(\frac{i}{n}\right)}\right)}{\frac{i}{n}} \]
    4. Applied egg-rr56.5%

      \[\leadsto 100 \cdot \frac{\color{blue}{\mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)}}{\frac{i}{n}} \]
    5. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto 100 \cdot \frac{e^{n \cdot \log \left(1 + \color{blue}{\frac{i}{n}}\right)} - 1}{\frac{i}{n}} \]
      2. lift-log1p.f64N/A

        \[\leadsto 100 \cdot \frac{e^{n \cdot \color{blue}{\mathsf{log1p}\left(\frac{i}{n}\right)}} - 1}{\frac{i}{n}} \]
      3. lift-*.f64N/A

        \[\leadsto 100 \cdot \frac{e^{\color{blue}{n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)}} - 1}{\frac{i}{n}} \]
      4. lift-/.f64N/A

        \[\leadsto 100 \cdot \frac{e^{n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)} - 1}{\color{blue}{\frac{i}{n}}} \]
      5. div-subN/A

        \[\leadsto 100 \cdot \color{blue}{\left(\frac{e^{n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)}}{\frac{i}{n}} - \frac{1}{\frac{i}{n}}\right)} \]
    6. Applied egg-rr51.4%

      \[\leadsto 100 \cdot \color{blue}{\mathsf{fma}\left(\frac{1}{i}, n \cdot {\left(\frac{i}{n} + 1\right)}^{n}, \frac{-n}{i}\right)} \]
    7. Taylor expanded in i around inf

      \[\leadsto 100 \cdot \mathsf{fma}\left(\frac{1}{i}, n \cdot {\color{blue}{\left(\frac{i}{n}\right)}}^{n}, \frac{\mathsf{neg}\left(n\right)}{i}\right) \]
    8. Step-by-step derivation
      1. lower-/.f6458.1

        \[\leadsto 100 \cdot \mathsf{fma}\left(\frac{1}{i}, n \cdot {\color{blue}{\left(\frac{i}{n}\right)}}^{n}, \frac{-n}{i}\right) \]
    9. Simplified58.1%

      \[\leadsto 100 \cdot \mathsf{fma}\left(\frac{1}{i}, n \cdot {\color{blue}{\left(\frac{i}{n}\right)}}^{n}, \frac{-n}{i}\right) \]
  3. Recombined 3 regimes into one program.
  4. Final simplification85.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;i \leq -6 \cdot 10^{-95}:\\ \;\;\;\;\frac{100}{i} \cdot \left(n \cdot \mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)\right)\\ \mathbf{elif}\;i \leq 2.8 \cdot 10^{-155}:\\ \;\;\;\;100 \cdot \left(n \cdot \left(\mathsf{fma}\left(i, \mathsf{fma}\left(i, 0.16666666666666666, 0.5\right), 1\right) + \frac{\frac{\left(i \cdot i\right) \cdot 0.3333333333333333}{n} - i \cdot \mathsf{fma}\left(i, 0.5, 0.5\right)}{n}\right)\right)\\ \mathbf{elif}\;i \leq 3.1 \cdot 10^{+117}:\\ \;\;\;\;\frac{100}{i} \cdot \left(n \cdot \mathsf{expm1}\left(n \cdot \mathsf{log1p}\left(\frac{i}{n}\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;100 \cdot \mathsf{fma}\left(\frac{1}{i}, n \cdot {\left(\frac{i}{n}\right)}^{n}, \frac{n}{-i}\right)\\ \end{array} \]
  5. Add Preprocessing

Developer Target 1: 33.6% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 1 + \frac{i}{n}\\ 100 \cdot \frac{e^{n \cdot \begin{array}{l} \mathbf{if}\;t\_0 = 1:\\ \;\;\;\;\frac{i}{n}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{i}{n} \cdot \log t\_0}{\left(\frac{i}{n} + 1\right) - 1}\\ \end{array}} - 1}{\frac{i}{n}} \end{array} \end{array} \]
(FPCore (i n)
 :precision binary64
 (let* ((t_0 (+ 1.0 (/ i n))))
   (*
    100.0
    (/
     (-
      (exp
       (*
        n
        (if (== t_0 1.0)
          (/ i n)
          (/ (* (/ i n) (log t_0)) (- (+ (/ i n) 1.0) 1.0)))))
      1.0)
     (/ i n)))))
double code(double i, double n) {
	double t_0 = 1.0 + (i / n);
	double tmp;
	if (t_0 == 1.0) {
		tmp = i / n;
	} else {
		tmp = ((i / n) * log(t_0)) / (((i / n) + 1.0) - 1.0);
	}
	return 100.0 * ((exp((n * tmp)) - 1.0) / (i / n));
}
real(8) function code(i, n)
    real(8), intent (in) :: i
    real(8), intent (in) :: n
    real(8) :: t_0
    real(8) :: tmp
    t_0 = 1.0d0 + (i / n)
    if (t_0 == 1.0d0) then
        tmp = i / n
    else
        tmp = ((i / n) * log(t_0)) / (((i / n) + 1.0d0) - 1.0d0)
    end if
    code = 100.0d0 * ((exp((n * tmp)) - 1.0d0) / (i / n))
end function
public static double code(double i, double n) {
	double t_0 = 1.0 + (i / n);
	double tmp;
	if (t_0 == 1.0) {
		tmp = i / n;
	} else {
		tmp = ((i / n) * Math.log(t_0)) / (((i / n) + 1.0) - 1.0);
	}
	return 100.0 * ((Math.exp((n * tmp)) - 1.0) / (i / n));
}
def code(i, n):
	t_0 = 1.0 + (i / n)
	tmp = 0
	if t_0 == 1.0:
		tmp = i / n
	else:
		tmp = ((i / n) * math.log(t_0)) / (((i / n) + 1.0) - 1.0)
	return 100.0 * ((math.exp((n * tmp)) - 1.0) / (i / n))
function code(i, n)
	t_0 = Float64(1.0 + Float64(i / n))
	tmp = 0.0
	if (t_0 == 1.0)
		tmp = Float64(i / n);
	else
		tmp = Float64(Float64(Float64(i / n) * log(t_0)) / Float64(Float64(Float64(i / n) + 1.0) - 1.0));
	end
	return Float64(100.0 * Float64(Float64(exp(Float64(n * tmp)) - 1.0) / Float64(i / n)))
end
function tmp_2 = code(i, n)
	t_0 = 1.0 + (i / n);
	tmp = 0.0;
	if (t_0 == 1.0)
		tmp = i / n;
	else
		tmp = ((i / n) * log(t_0)) / (((i / n) + 1.0) - 1.0);
	end
	tmp_2 = 100.0 * ((exp((n * tmp)) - 1.0) / (i / n));
end
code[i_, n_] := Block[{t$95$0 = N[(1.0 + N[(i / n), $MachinePrecision]), $MachinePrecision]}, N[(100.0 * N[(N[(N[Exp[N[(n * If[Equal[t$95$0, 1.0], N[(i / n), $MachinePrecision], N[(N[(N[(i / n), $MachinePrecision] * N[Log[t$95$0], $MachinePrecision]), $MachinePrecision] / N[(N[(N[(i / n), $MachinePrecision] + 1.0), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]]), $MachinePrecision]], $MachinePrecision] - 1.0), $MachinePrecision] / N[(i / n), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := 1 + \frac{i}{n}\\
100 \cdot \frac{e^{n \cdot \begin{array}{l}
\mathbf{if}\;t\_0 = 1:\\
\;\;\;\;\frac{i}{n}\\

\mathbf{else}:\\
\;\;\;\;\frac{\frac{i}{n} \cdot \log t\_0}{\left(\frac{i}{n} + 1\right) - 1}\\


\end{array}} - 1}{\frac{i}{n}}
\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2024218 
(FPCore (i n)
  :name "Compound Interest"
  :precision binary64

  :alt
  (! :herbie-platform default (let ((lnbase (if (== (+ 1 (/ i n)) 1) (/ i n) (/ (* (/ i n) (log (+ 1 (/ i n)))) (- (+ (/ i n) 1) 1))))) (* 100 (/ (- (exp (* n lnbase)) 1) (/ i n)))))

  (* 100.0 (/ (- (pow (+ 1.0 (/ i n)) n) 1.0) (/ i n))))