math.square on complex, real part

Percentage Accurate: 93.8% → 100.0%
Time: 4.6s
Alternatives: 3
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ re \cdot re - im \cdot im \end{array} \]
(FPCore re_sqr (re im) :precision binary64 (- (* re re) (* im im)))
double re_sqr(double re, double im) {
	return (re * re) - (im * im);
}
real(8) function re_sqr(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    re_sqr = (re * re) - (im * im)
end function
public static double re_sqr(double re, double im) {
	return (re * re) - (im * im);
}
def re_sqr(re, im):
	return (re * re) - (im * im)
function re_sqr(re, im)
	return Float64(Float64(re * re) - Float64(im * im))
end
function tmp = re_sqr(re, im)
	tmp = (re * re) - (im * im);
end
re$95$sqr[re_, im_] := N[(N[(re * re), $MachinePrecision] - N[(im * im), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
re \cdot re - im \cdot im
\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 3 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: 93.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ re \cdot re - im \cdot im \end{array} \]
(FPCore re_sqr (re im) :precision binary64 (- (* re re) (* im im)))
double re_sqr(double re, double im) {
	return (re * re) - (im * im);
}
real(8) function re_sqr(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    re_sqr = (re * re) - (im * im)
end function
public static double re_sqr(double re, double im) {
	return (re * re) - (im * im);
}
def re_sqr(re, im):
	return (re * re) - (im * im)
function re_sqr(re, im)
	return Float64(Float64(re * re) - Float64(im * im))
end
function tmp = re_sqr(re, im)
	tmp = (re * re) - (im * im);
end
re$95$sqr[re_, im_] := N[(N[(re * re), $MachinePrecision] - N[(im * im), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
re \cdot re - im \cdot im
\end{array}

Alternative 1: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(re - im\right) \cdot \left(re + im\right) \end{array} \]
(FPCore re_sqr (re im) :precision binary64 (* (- re im) (+ re im)))
double re_sqr(double re, double im) {
	return (re - im) * (re + im);
}
real(8) function re_sqr(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    re_sqr = (re - im) * (re + im)
end function
public static double re_sqr(double re, double im) {
	return (re - im) * (re + im);
}
def re_sqr(re, im):
	return (re - im) * (re + im)
function re_sqr(re, im)
	return Float64(Float64(re - im) * Float64(re + im))
end
function tmp = re_sqr(re, im)
	tmp = (re - im) * (re + im);
end
re$95$sqr[re_, im_] := N[(N[(re - im), $MachinePrecision] * N[(re + im), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(re - im\right) \cdot \left(re + im\right)
\end{array}
Derivation
  1. Initial program 95.3%

    \[re \cdot re - im \cdot im \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. difference-of-squares100.0%

      \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re - im\right)} \]
    2. add-sqr-sqrt49.5%

      \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \cdot \left(re - im\right) \]
    3. sqrt-prod79.0%

      \[\leadsto \left(re + \color{blue}{\sqrt{im \cdot im}}\right) \cdot \left(re - im\right) \]
    4. sqr-neg79.0%

      \[\leadsto \left(re + \sqrt{\color{blue}{\left(-im\right) \cdot \left(-im\right)}}\right) \cdot \left(re - im\right) \]
    5. sqrt-unprod29.8%

      \[\leadsto \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \cdot \left(re - im\right) \]
    6. add-sqr-sqrt49.6%

      \[\leadsto \left(re + \color{blue}{\left(-im\right)}\right) \cdot \left(re - im\right) \]
    7. sub-neg49.6%

      \[\leadsto \color{blue}{\left(re - im\right)} \cdot \left(re - im\right) \]
    8. pow149.6%

      \[\leadsto \color{blue}{{\left(re - im\right)}^{1}} \cdot \left(re - im\right) \]
    9. pow149.6%

      \[\leadsto {\left(re - im\right)}^{1} \cdot \color{blue}{{\left(re - im\right)}^{1}} \]
    10. pow-prod-up49.6%

      \[\leadsto \color{blue}{{\left(re - im\right)}^{\left(1 + 1\right)}} \]
    11. add-sqr-sqrt26.4%

      \[\leadsto {\left(\color{blue}{\sqrt{re} \cdot \sqrt{re}} - im\right)}^{\left(1 + 1\right)} \]
    12. add-sqr-sqrt10.2%

      \[\leadsto {\left(\sqrt{re} \cdot \sqrt{re} - \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right)}^{\left(1 + 1\right)} \]
    13. difference-of-squares10.2%

      \[\leadsto {\color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)}}^{\left(1 + 1\right)} \]
    14. metadata-eval10.2%

      \[\leadsto {\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)}^{\color{blue}{2}} \]
    15. unpow-prod-down10.2%

      \[\leadsto \color{blue}{{\left(\sqrt{re} + \sqrt{im}\right)}^{2} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2}} \]
  4. Applied egg-rr10.2%

    \[\leadsto \color{blue}{{\left(\sqrt{re} + \sqrt{im}\right)}^{2} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2}} \]
  5. Step-by-step derivation
    1. unpow210.2%

      \[\leadsto \color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} + \sqrt{im}\right)\right)} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2} \]
    2. unpow210.2%

      \[\leadsto \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} + \sqrt{im}\right)\right) \cdot \color{blue}{\left(\left(\sqrt{re} - \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)} \]
    3. unswap-sqr10.2%

      \[\leadsto \color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)} \]
    4. difference-of-squares10.2%

      \[\leadsto \color{blue}{\left(\sqrt{re} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right)} \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    5. unpow1/210.2%

      \[\leadsto \left(\color{blue}{{re}^{0.5}} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    6. unpow1/210.2%

      \[\leadsto \left({re}^{0.5} \cdot \color{blue}{{re}^{0.5}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    7. pow-sqr10.2%

      \[\leadsto \left(\color{blue}{{re}^{\left(2 \cdot 0.5\right)}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    8. metadata-eval10.2%

      \[\leadsto \left({re}^{\color{blue}{1}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    9. unpow110.2%

      \[\leadsto \left(\color{blue}{re} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    10. unpow1/210.2%

      \[\leadsto \left(re - \color{blue}{{im}^{0.5}} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    11. unpow1/210.2%

      \[\leadsto \left(re - {im}^{0.5} \cdot \color{blue}{{im}^{0.5}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    12. pow-sqr10.2%

      \[\leadsto \left(re - \color{blue}{{im}^{\left(2 \cdot 0.5\right)}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    13. metadata-eval10.2%

      \[\leadsto \left(re - {im}^{\color{blue}{1}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    14. unpow110.2%

      \[\leadsto \left(re - \color{blue}{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    15. difference-of-squares10.2%

      \[\leadsto \left(re - im\right) \cdot \color{blue}{\left(\sqrt{re} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right)} \]
    16. unpow1/210.2%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{{re}^{0.5}} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right) \]
    17. unpow1/210.2%

      \[\leadsto \left(re - im\right) \cdot \left({re}^{0.5} \cdot \color{blue}{{re}^{0.5}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    18. pow-sqr19.8%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{{re}^{\left(2 \cdot 0.5\right)}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    19. metadata-eval19.8%

      \[\leadsto \left(re - im\right) \cdot \left({re}^{\color{blue}{1}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    20. unpow119.8%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{re} - \sqrt{im} \cdot \sqrt{im}\right) \]
  6. Simplified49.6%

    \[\leadsto \color{blue}{\left(re - im\right) \cdot \left(re - im\right)} \]
  7. Applied egg-rr22.5%

    \[\leadsto \color{blue}{\frac{{\left(re + im\right)}^{2} \cdot \left({re}^{3} - {im}^{3}\right)}{\left(re + im\right) \cdot \mathsf{fma}\left(im, re + im, {re}^{2}\right)}} \]
  8. Step-by-step derivation
    1. times-frac37.0%

      \[\leadsto \color{blue}{\frac{{\left(re + im\right)}^{2}}{re + im} \cdot \frac{{re}^{3} - {im}^{3}}{\mathsf{fma}\left(im, re + im, {re}^{2}\right)}} \]
    2. associate-*r/30.0%

      \[\leadsto \color{blue}{\frac{\frac{{\left(re + im\right)}^{2}}{re + im} \cdot \left({re}^{3} - {im}^{3}\right)}{\mathsf{fma}\left(im, re + im, {re}^{2}\right)}} \]
    3. unpow230.0%

      \[\leadsto \frac{\frac{\color{blue}{\left(re + im\right) \cdot \left(re + im\right)}}{re + im} \cdot \left({re}^{3} - {im}^{3}\right)}{\mathsf{fma}\left(im, re + im, {re}^{2}\right)} \]
    4. associate-/l*30.0%

      \[\leadsto \frac{\color{blue}{\frac{re + im}{\frac{re + im}{re + im}}} \cdot \left({re}^{3} - {im}^{3}\right)}{\mathsf{fma}\left(im, re + im, {re}^{2}\right)} \]
    5. *-inverses30.0%

      \[\leadsto \frac{\frac{re + im}{\color{blue}{1}} \cdot \left({re}^{3} - {im}^{3}\right)}{\mathsf{fma}\left(im, re + im, {re}^{2}\right)} \]
    6. /-rgt-identity30.0%

      \[\leadsto \frac{\color{blue}{\left(re + im\right)} \cdot \left({re}^{3} - {im}^{3}\right)}{\mathsf{fma}\left(im, re + im, {re}^{2}\right)} \]
    7. associate-/l*36.9%

      \[\leadsto \color{blue}{\frac{re + im}{\frac{\mathsf{fma}\left(im, re + im, {re}^{2}\right)}{{re}^{3} - {im}^{3}}}} \]
    8. +-commutative36.9%

      \[\leadsto \frac{\color{blue}{im + re}}{\frac{\mathsf{fma}\left(im, re + im, {re}^{2}\right)}{{re}^{3} - {im}^{3}}} \]
    9. +-commutative36.9%

      \[\leadsto \frac{im + re}{\frac{\mathsf{fma}\left(im, \color{blue}{im + re}, {re}^{2}\right)}{{re}^{3} - {im}^{3}}} \]
  9. Simplified36.9%

    \[\leadsto \color{blue}{\frac{im + re}{\frac{\mathsf{fma}\left(im, im + re, {re}^{2}\right)}{{re}^{3} - {im}^{3}}}} \]
  10. Step-by-step derivation
    1. clear-num36.8%

      \[\leadsto \color{blue}{\frac{1}{\frac{\frac{\mathsf{fma}\left(im, im + re, {re}^{2}\right)}{{re}^{3} - {im}^{3}}}{im + re}}} \]
    2. associate-/r/36.9%

      \[\leadsto \color{blue}{\frac{1}{\frac{\mathsf{fma}\left(im, im + re, {re}^{2}\right)}{{re}^{3} - {im}^{3}}} \cdot \left(im + re\right)} \]
    3. clear-num37.0%

      \[\leadsto \color{blue}{\frac{{re}^{3} - {im}^{3}}{\mathsf{fma}\left(im, im + re, {re}^{2}\right)}} \cdot \left(im + re\right) \]
    4. fma-udef36.9%

      \[\leadsto \frac{{re}^{3} - {im}^{3}}{\color{blue}{im \cdot \left(im + re\right) + {re}^{2}}} \cdot \left(im + re\right) \]
    5. +-commutative36.9%

      \[\leadsto \frac{{re}^{3} - {im}^{3}}{\color{blue}{{re}^{2} + im \cdot \left(im + re\right)}} \cdot \left(im + re\right) \]
    6. distribute-rgt-in36.9%

      \[\leadsto \frac{{re}^{3} - {im}^{3}}{{re}^{2} + \color{blue}{\left(im \cdot im + re \cdot im\right)}} \cdot \left(im + re\right) \]
    7. unpow236.9%

      \[\leadsto \frac{{re}^{3} - {im}^{3}}{\color{blue}{re \cdot re} + \left(im \cdot im + re \cdot im\right)} \cdot \left(im + re\right) \]
    8. flip3--100.0%

      \[\leadsto \color{blue}{\left(re - im\right)} \cdot \left(im + re\right) \]
    9. +-commutative100.0%

      \[\leadsto \left(re - im\right) \cdot \color{blue}{\left(re + im\right)} \]
  11. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\left(re - im\right) \cdot \left(re + im\right)} \]
  12. Final simplification100.0%

    \[\leadsto \left(re - im\right) \cdot \left(re + im\right) \]
  13. Add Preprocessing

Alternative 2: 57.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ re \cdot \left(re + im \cdot -2\right) \end{array} \]
(FPCore re_sqr (re im) :precision binary64 (* re (+ re (* im -2.0))))
double re_sqr(double re, double im) {
	return re * (re + (im * -2.0));
}
real(8) function re_sqr(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    re_sqr = re * (re + (im * (-2.0d0)))
end function
public static double re_sqr(double re, double im) {
	return re * (re + (im * -2.0));
}
def re_sqr(re, im):
	return re * (re + (im * -2.0))
function re_sqr(re, im)
	return Float64(re * Float64(re + Float64(im * -2.0)))
end
function tmp = re_sqr(re, im)
	tmp = re * (re + (im * -2.0));
end
re$95$sqr[re_, im_] := N[(re * N[(re + N[(im * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
re \cdot \left(re + im \cdot -2\right)
\end{array}
Derivation
  1. Initial program 95.3%

    \[re \cdot re - im \cdot im \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. difference-of-squares100.0%

      \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re - im\right)} \]
    2. add-sqr-sqrt49.5%

      \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \cdot \left(re - im\right) \]
    3. sqrt-prod79.0%

      \[\leadsto \left(re + \color{blue}{\sqrt{im \cdot im}}\right) \cdot \left(re - im\right) \]
    4. sqr-neg79.0%

      \[\leadsto \left(re + \sqrt{\color{blue}{\left(-im\right) \cdot \left(-im\right)}}\right) \cdot \left(re - im\right) \]
    5. sqrt-unprod29.8%

      \[\leadsto \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \cdot \left(re - im\right) \]
    6. add-sqr-sqrt49.6%

      \[\leadsto \left(re + \color{blue}{\left(-im\right)}\right) \cdot \left(re - im\right) \]
    7. sub-neg49.6%

      \[\leadsto \color{blue}{\left(re - im\right)} \cdot \left(re - im\right) \]
    8. pow149.6%

      \[\leadsto \color{blue}{{\left(re - im\right)}^{1}} \cdot \left(re - im\right) \]
    9. pow149.6%

      \[\leadsto {\left(re - im\right)}^{1} \cdot \color{blue}{{\left(re - im\right)}^{1}} \]
    10. pow-prod-up49.6%

      \[\leadsto \color{blue}{{\left(re - im\right)}^{\left(1 + 1\right)}} \]
    11. add-sqr-sqrt26.4%

      \[\leadsto {\left(\color{blue}{\sqrt{re} \cdot \sqrt{re}} - im\right)}^{\left(1 + 1\right)} \]
    12. add-sqr-sqrt10.2%

      \[\leadsto {\left(\sqrt{re} \cdot \sqrt{re} - \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right)}^{\left(1 + 1\right)} \]
    13. difference-of-squares10.2%

      \[\leadsto {\color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)}}^{\left(1 + 1\right)} \]
    14. metadata-eval10.2%

      \[\leadsto {\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)}^{\color{blue}{2}} \]
    15. unpow-prod-down10.2%

      \[\leadsto \color{blue}{{\left(\sqrt{re} + \sqrt{im}\right)}^{2} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2}} \]
  4. Applied egg-rr10.2%

    \[\leadsto \color{blue}{{\left(\sqrt{re} + \sqrt{im}\right)}^{2} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2}} \]
  5. Step-by-step derivation
    1. unpow210.2%

      \[\leadsto \color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} + \sqrt{im}\right)\right)} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2} \]
    2. unpow210.2%

      \[\leadsto \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} + \sqrt{im}\right)\right) \cdot \color{blue}{\left(\left(\sqrt{re} - \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)} \]
    3. unswap-sqr10.2%

      \[\leadsto \color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)} \]
    4. difference-of-squares10.2%

      \[\leadsto \color{blue}{\left(\sqrt{re} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right)} \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    5. unpow1/210.2%

      \[\leadsto \left(\color{blue}{{re}^{0.5}} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    6. unpow1/210.2%

      \[\leadsto \left({re}^{0.5} \cdot \color{blue}{{re}^{0.5}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    7. pow-sqr10.2%

      \[\leadsto \left(\color{blue}{{re}^{\left(2 \cdot 0.5\right)}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    8. metadata-eval10.2%

      \[\leadsto \left({re}^{\color{blue}{1}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    9. unpow110.2%

      \[\leadsto \left(\color{blue}{re} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    10. unpow1/210.2%

      \[\leadsto \left(re - \color{blue}{{im}^{0.5}} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    11. unpow1/210.2%

      \[\leadsto \left(re - {im}^{0.5} \cdot \color{blue}{{im}^{0.5}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    12. pow-sqr10.2%

      \[\leadsto \left(re - \color{blue}{{im}^{\left(2 \cdot 0.5\right)}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    13. metadata-eval10.2%

      \[\leadsto \left(re - {im}^{\color{blue}{1}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    14. unpow110.2%

      \[\leadsto \left(re - \color{blue}{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    15. difference-of-squares10.2%

      \[\leadsto \left(re - im\right) \cdot \color{blue}{\left(\sqrt{re} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right)} \]
    16. unpow1/210.2%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{{re}^{0.5}} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right) \]
    17. unpow1/210.2%

      \[\leadsto \left(re - im\right) \cdot \left({re}^{0.5} \cdot \color{blue}{{re}^{0.5}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    18. pow-sqr19.8%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{{re}^{\left(2 \cdot 0.5\right)}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    19. metadata-eval19.8%

      \[\leadsto \left(re - im\right) \cdot \left({re}^{\color{blue}{1}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    20. unpow119.8%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{re} - \sqrt{im} \cdot \sqrt{im}\right) \]
  6. Simplified49.6%

    \[\leadsto \color{blue}{\left(re - im\right) \cdot \left(re - im\right)} \]
  7. Taylor expanded in re around inf 49.4%

    \[\leadsto \color{blue}{-2 \cdot \left(im \cdot re\right) + {re}^{2}} \]
  8. Step-by-step derivation
    1. associate-*r*49.4%

      \[\leadsto \color{blue}{\left(-2 \cdot im\right) \cdot re} + {re}^{2} \]
    2. unpow249.4%

      \[\leadsto \left(-2 \cdot im\right) \cdot re + \color{blue}{re \cdot re} \]
    3. distribute-rgt-out53.7%

      \[\leadsto \color{blue}{re \cdot \left(-2 \cdot im + re\right)} \]
    4. *-commutative53.7%

      \[\leadsto re \cdot \left(\color{blue}{im \cdot -2} + re\right) \]
  9. Simplified53.7%

    \[\leadsto \color{blue}{re \cdot \left(im \cdot -2 + re\right)} \]
  10. Final simplification53.7%

    \[\leadsto re \cdot \left(re + im \cdot -2\right) \]
  11. Add Preprocessing

Alternative 3: 15.7% accurate, 1.4× speedup?

\[\begin{array}{l} \\ -2 \cdot \left(re \cdot im\right) \end{array} \]
(FPCore re_sqr (re im) :precision binary64 (* -2.0 (* re im)))
double re_sqr(double re, double im) {
	return -2.0 * (re * im);
}
real(8) function re_sqr(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    re_sqr = (-2.0d0) * (re * im)
end function
public static double re_sqr(double re, double im) {
	return -2.0 * (re * im);
}
def re_sqr(re, im):
	return -2.0 * (re * im)
function re_sqr(re, im)
	return Float64(-2.0 * Float64(re * im))
end
function tmp = re_sqr(re, im)
	tmp = -2.0 * (re * im);
end
re$95$sqr[re_, im_] := N[(-2.0 * N[(re * im), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
-2 \cdot \left(re \cdot im\right)
\end{array}
Derivation
  1. Initial program 95.3%

    \[re \cdot re - im \cdot im \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. difference-of-squares100.0%

      \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re - im\right)} \]
    2. add-sqr-sqrt49.5%

      \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \cdot \left(re - im\right) \]
    3. sqrt-prod79.0%

      \[\leadsto \left(re + \color{blue}{\sqrt{im \cdot im}}\right) \cdot \left(re - im\right) \]
    4. sqr-neg79.0%

      \[\leadsto \left(re + \sqrt{\color{blue}{\left(-im\right) \cdot \left(-im\right)}}\right) \cdot \left(re - im\right) \]
    5. sqrt-unprod29.8%

      \[\leadsto \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \cdot \left(re - im\right) \]
    6. add-sqr-sqrt49.6%

      \[\leadsto \left(re + \color{blue}{\left(-im\right)}\right) \cdot \left(re - im\right) \]
    7. sub-neg49.6%

      \[\leadsto \color{blue}{\left(re - im\right)} \cdot \left(re - im\right) \]
    8. pow149.6%

      \[\leadsto \color{blue}{{\left(re - im\right)}^{1}} \cdot \left(re - im\right) \]
    9. pow149.6%

      \[\leadsto {\left(re - im\right)}^{1} \cdot \color{blue}{{\left(re - im\right)}^{1}} \]
    10. pow-prod-up49.6%

      \[\leadsto \color{blue}{{\left(re - im\right)}^{\left(1 + 1\right)}} \]
    11. add-sqr-sqrt26.4%

      \[\leadsto {\left(\color{blue}{\sqrt{re} \cdot \sqrt{re}} - im\right)}^{\left(1 + 1\right)} \]
    12. add-sqr-sqrt10.2%

      \[\leadsto {\left(\sqrt{re} \cdot \sqrt{re} - \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right)}^{\left(1 + 1\right)} \]
    13. difference-of-squares10.2%

      \[\leadsto {\color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)}}^{\left(1 + 1\right)} \]
    14. metadata-eval10.2%

      \[\leadsto {\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)}^{\color{blue}{2}} \]
    15. unpow-prod-down10.2%

      \[\leadsto \color{blue}{{\left(\sqrt{re} + \sqrt{im}\right)}^{2} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2}} \]
  4. Applied egg-rr10.2%

    \[\leadsto \color{blue}{{\left(\sqrt{re} + \sqrt{im}\right)}^{2} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2}} \]
  5. Step-by-step derivation
    1. unpow210.2%

      \[\leadsto \color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} + \sqrt{im}\right)\right)} \cdot {\left(\sqrt{re} - \sqrt{im}\right)}^{2} \]
    2. unpow210.2%

      \[\leadsto \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} + \sqrt{im}\right)\right) \cdot \color{blue}{\left(\left(\sqrt{re} - \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)} \]
    3. unswap-sqr10.2%

      \[\leadsto \color{blue}{\left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right)} \]
    4. difference-of-squares10.2%

      \[\leadsto \color{blue}{\left(\sqrt{re} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right)} \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    5. unpow1/210.2%

      \[\leadsto \left(\color{blue}{{re}^{0.5}} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    6. unpow1/210.2%

      \[\leadsto \left({re}^{0.5} \cdot \color{blue}{{re}^{0.5}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    7. pow-sqr10.2%

      \[\leadsto \left(\color{blue}{{re}^{\left(2 \cdot 0.5\right)}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    8. metadata-eval10.2%

      \[\leadsto \left({re}^{\color{blue}{1}} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    9. unpow110.2%

      \[\leadsto \left(\color{blue}{re} - \sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    10. unpow1/210.2%

      \[\leadsto \left(re - \color{blue}{{im}^{0.5}} \cdot \sqrt{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    11. unpow1/210.2%

      \[\leadsto \left(re - {im}^{0.5} \cdot \color{blue}{{im}^{0.5}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    12. pow-sqr10.2%

      \[\leadsto \left(re - \color{blue}{{im}^{\left(2 \cdot 0.5\right)}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    13. metadata-eval10.2%

      \[\leadsto \left(re - {im}^{\color{blue}{1}}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    14. unpow110.2%

      \[\leadsto \left(re - \color{blue}{im}\right) \cdot \left(\left(\sqrt{re} + \sqrt{im}\right) \cdot \left(\sqrt{re} - \sqrt{im}\right)\right) \]
    15. difference-of-squares10.2%

      \[\leadsto \left(re - im\right) \cdot \color{blue}{\left(\sqrt{re} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right)} \]
    16. unpow1/210.2%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{{re}^{0.5}} \cdot \sqrt{re} - \sqrt{im} \cdot \sqrt{im}\right) \]
    17. unpow1/210.2%

      \[\leadsto \left(re - im\right) \cdot \left({re}^{0.5} \cdot \color{blue}{{re}^{0.5}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    18. pow-sqr19.8%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{{re}^{\left(2 \cdot 0.5\right)}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    19. metadata-eval19.8%

      \[\leadsto \left(re - im\right) \cdot \left({re}^{\color{blue}{1}} - \sqrt{im} \cdot \sqrt{im}\right) \]
    20. unpow119.8%

      \[\leadsto \left(re - im\right) \cdot \left(\color{blue}{re} - \sqrt{im} \cdot \sqrt{im}\right) \]
  6. Simplified49.6%

    \[\leadsto \color{blue}{\left(re - im\right) \cdot \left(re - im\right)} \]
  7. Taylor expanded in re around inf 49.4%

    \[\leadsto \color{blue}{-2 \cdot \left(im \cdot re\right) + {re}^{2}} \]
  8. Step-by-step derivation
    1. associate-*r*49.4%

      \[\leadsto \color{blue}{\left(-2 \cdot im\right) \cdot re} + {re}^{2} \]
    2. unpow249.4%

      \[\leadsto \left(-2 \cdot im\right) \cdot re + \color{blue}{re \cdot re} \]
    3. distribute-rgt-out53.7%

      \[\leadsto \color{blue}{re \cdot \left(-2 \cdot im + re\right)} \]
    4. *-commutative53.7%

      \[\leadsto re \cdot \left(\color{blue}{im \cdot -2} + re\right) \]
  9. Simplified53.7%

    \[\leadsto \color{blue}{re \cdot \left(im \cdot -2 + re\right)} \]
  10. Taylor expanded in re around 0 13.6%

    \[\leadsto \color{blue}{-2 \cdot \left(im \cdot re\right)} \]
  11. Final simplification13.6%

    \[\leadsto -2 \cdot \left(re \cdot im\right) \]
  12. Add Preprocessing

Reproduce

?
herbie shell --seed 2024029 
(FPCore re_sqr (re im)
  :name "math.square on complex, real part"
  :precision binary64
  (- (* re re) (* im im)))