Average Error: 47.5 → 11.2
Time: 4.5m
Precision: 64
Internal Precision: 3392
\[100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}}\]
↓
\[\begin{array}{l} \mathbf{if}\;i \le -1.4597379955744417 \cdot 10^{-06}:\\ \;\;\;\;100 \cdot \frac{e^{n \cdot \log_* (1 + \frac{i}{n})} - 1}{\frac{i}{n}}\\ \mathbf{if}\;i \le 1.2350772268671153 \cdot 10^{-12}:\\ \;\;\;\;\left(n \cdot \frac{1}{2}\right) \cdot \left(100 \cdot i\right) + 100 \cdot n\\ \mathbf{else}:\\ \;\;\;\;\left(n \cdot \frac{100}{i}\right) \cdot \left(\frac{{i}^{n}}{{n}^{n}} - 1\right)\\ \end{array}\]

Error

Bits error versus i

Bits error versus n

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Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original47.5
Target46.9
Herbie11.2
\[100 \cdot \frac{e^{n \cdot \begin{array}{l} \mathbf{if}\;1 + \frac{i}{n} = 1:\\ \;\;\;\;\frac{i}{n}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{i}{n} \cdot \log \left(1 + \frac{i}{n}\right)}{\left(\frac{i}{n} + 1\right) - 1}\\ \end{array}} - 1}{\frac{i}{n}}\]

Derivation

  1. Split input into 3 regimes

  2. if i < -1.4597379955744417e-06

    1. Initial program 28.8

      \[100 \cdot \frac{{\left(1 + \frac{i}{n}\right)}^{n} - 1}{\frac{i}{n}}\]
    2. Using strategy rm

    3. Applied add-exp-log28.8

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

    4. Applied pow-exp28.8

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

    5. Applied simplify5.7

      \[\leadsto 100 \cdot \frac{e^{\color{blue}{n \cdot \log_* (1 + \frac{i}{n})}} - 1}{\frac{i}{n}}\]

    if -1.4597379955744417e-06 < i < 1.2350772268671153e-12

    1. Initial program 57.8

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

    2. Taylor expanded around 0 57.5

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

    3. Applied simplify26.1

      \[\leadsto \color{blue}{\frac{100}{\frac{i}{n}} \cdot (i \cdot \left(i \cdot \frac{1}{2}\right) + i)_*}\]
    4. Using strategy rm

    5. Applied fma-udef26.1

      \[\leadsto \frac{100}{\frac{i}{n}} \cdot \color{blue}{\left(i \cdot \left(i \cdot \frac{1}{2}\right) + i\right)}\]

    6. Applied distribute-lft-in26.6

      \[\leadsto \color{blue}{\frac{100}{\frac{i}{n}} \cdot \left(i \cdot \left(i \cdot \frac{1}{2}\right)\right) + \frac{100}{\frac{i}{n}} \cdot i}\]

    7. Applied simplify26.1

      \[\leadsto \color{blue}{\left(n \cdot \frac{1}{2}\right) \cdot \left(100 \cdot i\right)} + \frac{100}{\frac{i}{n}} \cdot i\]

    8. Applied simplify8.8

      \[\leadsto \left(n \cdot \frac{1}{2}\right) \cdot \left(100 \cdot i\right) + \color{blue}{100 \cdot n}\]

    if 1.2350772268671153e-12 < i

    1. Initial program 33.1

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

    2. Taylor expanded around inf 31.1

      \[\leadsto 100 \cdot \frac{\color{blue}{e^{n \cdot \left(\log \left(\frac{1}{n}\right) - \log \left(\frac{1}{i}\right)\right)} - 1}}{\frac{i}{n}}\]

    3. Applied simplify31.0

      \[\leadsto \color{blue}{\left(n \cdot \frac{100}{i}\right) \cdot \left(\frac{{i}^{n}}{{n}^{n}} - 1\right)}\]
  3. Recombined 3 regimes into one program.

Runtime

Time bar (total: 4.5m)Debug logProfile

herbie shell --seed '#(1072967564 1937075727 894099792 790700740 1036514779 1027793188)' +o rules:numerics
(FPCore (i n)
  :name "Compound Interest"

  :herbie-target
  (* 100 (/ (- (exp (* n (if (== (+ 1 (/ i n)) 1) (/ i n) (/ (* (/ i n) (log (+ 1 (/ i n)))) (- (+ (/ i n) 1) 1))))) 1) (/ i n)))

  (* 100 (/ (- (pow (+ 1 (/ i n)) n) 1) (/ i n))))