math.square on complex, real part

Percentage Accurate: 93.5% → 100.0%
Time: 6.2s
Alternatives: 5
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 5 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: 93.5% 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 94.1%

    \[re \cdot re - im \cdot im \]
  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. sub-neg100.0%

      \[\leadsto \left(re + im\right) \cdot \color{blue}{\left(re + \left(-im\right)\right)} \]
    3. add-sqr-sqrt48.3%

      \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \]
    4. sqrt-unprod75.5%

      \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{\left(-im\right) \cdot \left(-im\right)}}\right) \]
    5. sqr-neg75.5%

      \[\leadsto \left(re + im\right) \cdot \left(re + \sqrt{\color{blue}{im \cdot im}}\right) \]
    6. sqrt-prod28.2%

      \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \]
    7. add-sqr-sqrt55.2%

      \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{im}\right) \]
  4. Applied egg-rr55.2%

    \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re + im\right)} \]
  5. Step-by-step derivation
    1. add-sqr-sqrt28.2%

      \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \cdot \left(re + im\right) \]
    2. sqrt-prod75.5%

      \[\leadsto \left(re + \color{blue}{\sqrt{im \cdot im}}\right) \cdot \left(re + im\right) \]
    3. add-sqr-sqrt28.2%

      \[\leadsto \left(re + \sqrt{im \cdot \color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)}}\right) \cdot \left(re + im\right) \]
    4. add-sqr-sqrt28.2%

      \[\leadsto \left(re + \sqrt{\color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)} \cdot \left(\sqrt{im} \cdot \sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
    5. sqr-neg28.2%

      \[\leadsto \left(re + \sqrt{\left(\sqrt{im} \cdot \sqrt{im}\right) \cdot \color{blue}{\left(\left(-\sqrt{im}\right) \cdot \left(-\sqrt{im}\right)\right)}}\right) \cdot \left(re + im\right) \]
    6. swap-sqr28.2%

      \[\leadsto \left(re + \sqrt{\color{blue}{\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)}}\right) \cdot \left(re + im\right) \]
    7. sqrt-unprod0.0%

      \[\leadsto \left(re + \color{blue}{\sqrt{\sqrt{im} \cdot \left(-\sqrt{im}\right)} \cdot \sqrt{\sqrt{im} \cdot \left(-\sqrt{im}\right)}}\right) \cdot \left(re + im\right) \]
    8. add-sqr-sqrt51.4%

      \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \left(-\sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
    9. distribute-rgt-neg-out51.4%

      \[\leadsto \left(re + \color{blue}{\left(-\sqrt{im} \cdot \sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
    10. add-sqr-sqrt100.0%

      \[\leadsto \left(re + \left(-\color{blue}{im}\right)\right) \cdot \left(re + im\right) \]
    11. sub-neg100.0%

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

    \[\leadsto \color{blue}{\left(re - im\right)} \cdot \left(re + im\right) \]
  7. Add Preprocessing

Alternative 2: 80.3% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;im \cdot im \leq 2 \cdot 10^{-185}:\\ \;\;\;\;re \cdot re\\ \mathbf{elif}\;im \cdot im \leq 2 \cdot 10^{-133}:\\ \;\;\;\;im \cdot \left(-im\right)\\ \mathbf{elif}\;im \cdot im \leq 2 \cdot 10^{-61}:\\ \;\;\;\;re \cdot re\\ \mathbf{else}:\\ \;\;\;\;im \cdot \left(re - im\right)\\ \end{array} \end{array} \]
(FPCore re_sqr (re im)
 :precision binary64
 (if (<= (* im im) 2e-185)
   (* re re)
   (if (<= (* im im) 2e-133)
     (* im (- im))
     (if (<= (* im im) 2e-61) (* re re) (* im (- re im))))))
double re_sqr(double re, double im) {
	double tmp;
	if ((im * im) <= 2e-185) {
		tmp = re * re;
	} else if ((im * im) <= 2e-133) {
		tmp = im * -im;
	} else if ((im * im) <= 2e-61) {
		tmp = re * re;
	} else {
		tmp = im * (re - im);
	}
	return tmp;
}
real(8) function re_sqr(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if ((im * im) <= 2d-185) then
        tmp = re * re
    else if ((im * im) <= 2d-133) then
        tmp = im * -im
    else if ((im * im) <= 2d-61) then
        tmp = re * re
    else
        tmp = im * (re - im)
    end if
    re_sqr = tmp
end function
public static double re_sqr(double re, double im) {
	double tmp;
	if ((im * im) <= 2e-185) {
		tmp = re * re;
	} else if ((im * im) <= 2e-133) {
		tmp = im * -im;
	} else if ((im * im) <= 2e-61) {
		tmp = re * re;
	} else {
		tmp = im * (re - im);
	}
	return tmp;
}
def re_sqr(re, im):
	tmp = 0
	if (im * im) <= 2e-185:
		tmp = re * re
	elif (im * im) <= 2e-133:
		tmp = im * -im
	elif (im * im) <= 2e-61:
		tmp = re * re
	else:
		tmp = im * (re - im)
	return tmp
function re_sqr(re, im)
	tmp = 0.0
	if (Float64(im * im) <= 2e-185)
		tmp = Float64(re * re);
	elseif (Float64(im * im) <= 2e-133)
		tmp = Float64(im * Float64(-im));
	elseif (Float64(im * im) <= 2e-61)
		tmp = Float64(re * re);
	else
		tmp = Float64(im * Float64(re - im));
	end
	return tmp
end
function tmp_2 = re_sqr(re, im)
	tmp = 0.0;
	if ((im * im) <= 2e-185)
		tmp = re * re;
	elseif ((im * im) <= 2e-133)
		tmp = im * -im;
	elseif ((im * im) <= 2e-61)
		tmp = re * re;
	else
		tmp = im * (re - im);
	end
	tmp_2 = tmp;
end
re$95$sqr[re_, im_] := If[LessEqual[N[(im * im), $MachinePrecision], 2e-185], N[(re * re), $MachinePrecision], If[LessEqual[N[(im * im), $MachinePrecision], 2e-133], N[(im * (-im)), $MachinePrecision], If[LessEqual[N[(im * im), $MachinePrecision], 2e-61], N[(re * re), $MachinePrecision], N[(im * N[(re - im), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;im \cdot im \leq 2 \cdot 10^{-185}:\\
\;\;\;\;re \cdot re\\

\mathbf{elif}\;im \cdot im \leq 2 \cdot 10^{-133}:\\
\;\;\;\;im \cdot \left(-im\right)\\

\mathbf{elif}\;im \cdot im \leq 2 \cdot 10^{-61}:\\
\;\;\;\;re \cdot re\\

\mathbf{else}:\\
\;\;\;\;im \cdot \left(re - im\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (*.f64 im im) < 2e-185 or 2.0000000000000001e-133 < (*.f64 im im) < 2.0000000000000001e-61

    1. Initial program 100.0%

      \[re \cdot re - im \cdot im \]
    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. sub-neg100.0%

        \[\leadsto \left(re + im\right) \cdot \color{blue}{\left(re + \left(-im\right)\right)} \]
      3. add-sqr-sqrt45.1%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \]
      4. sqrt-unprod93.7%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{\left(-im\right) \cdot \left(-im\right)}}\right) \]
      5. sqr-neg93.7%

        \[\leadsto \left(re + im\right) \cdot \left(re + \sqrt{\color{blue}{im \cdot im}}\right) \]
      6. sqrt-prod48.6%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \]
      7. add-sqr-sqrt91.2%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{im}\right) \]
    4. Applied egg-rr91.2%

      \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re + im\right)} \]
    5. Taylor expanded in re around inf 91.4%

      \[\leadsto \left(re + im\right) \cdot \color{blue}{re} \]
    6. Taylor expanded in re around inf 91.9%

      \[\leadsto \color{blue}{re} \cdot re \]

    if 2e-185 < (*.f64 im im) < 2.0000000000000001e-133

    1. Initial program 99.9%

      \[re \cdot re - im \cdot im \]
    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. sub-neg100.0%

        \[\leadsto \left(re + im\right) \cdot \color{blue}{\left(re + \left(-im\right)\right)} \]
      3. add-sqr-sqrt43.4%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \]
      4. sqrt-unprod57.7%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{\left(-im\right) \cdot \left(-im\right)}}\right) \]
      5. sqr-neg57.7%

        \[\leadsto \left(re + im\right) \cdot \left(re + \sqrt{\color{blue}{im \cdot im}}\right) \]
      6. sqrt-prod13.9%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \]
      7. add-sqr-sqrt27.4%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{im}\right) \]
    4. Applied egg-rr27.4%

      \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re + im\right)} \]
    5. Step-by-step derivation
      1. add-sqr-sqrt13.9%

        \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \cdot \left(re + im\right) \]
      2. sqrt-prod57.7%

        \[\leadsto \left(re + \color{blue}{\sqrt{im \cdot im}}\right) \cdot \left(re + im\right) \]
      3. add-sqr-sqrt13.9%

        \[\leadsto \left(re + \sqrt{im \cdot \color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)}}\right) \cdot \left(re + im\right) \]
      4. add-sqr-sqrt13.9%

        \[\leadsto \left(re + \sqrt{\color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)} \cdot \left(\sqrt{im} \cdot \sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      5. sqr-neg13.9%

        \[\leadsto \left(re + \sqrt{\left(\sqrt{im} \cdot \sqrt{im}\right) \cdot \color{blue}{\left(\left(-\sqrt{im}\right) \cdot \left(-\sqrt{im}\right)\right)}}\right) \cdot \left(re + im\right) \]
      6. swap-sqr13.9%

        \[\leadsto \left(re + \sqrt{\color{blue}{\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)}}\right) \cdot \left(re + im\right) \]
      7. sqrt-unprod0.0%

        \[\leadsto \left(re + \color{blue}{\sqrt{\sqrt{im} \cdot \left(-\sqrt{im}\right)} \cdot \sqrt{\sqrt{im} \cdot \left(-\sqrt{im}\right)}}\right) \cdot \left(re + im\right) \]
      8. add-sqr-sqrt55.8%

        \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \left(-\sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      9. distribute-rgt-neg-out55.8%

        \[\leadsto \left(re + \color{blue}{\left(-\sqrt{im} \cdot \sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      10. add-sqr-sqrt100.0%

        \[\leadsto \left(re + \left(-\color{blue}{im}\right)\right) \cdot \left(re + im\right) \]
      11. sub-neg100.0%

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

      \[\leadsto \color{blue}{\left(re - im\right)} \cdot \left(re + im\right) \]
    7. Taylor expanded in re around 0 72.5%

      \[\leadsto \left(re - im\right) \cdot \color{blue}{im} \]
    8. Taylor expanded in re around 0 74.2%

      \[\leadsto \color{blue}{\left(-1 \cdot im\right)} \cdot im \]
    9. Step-by-step derivation
      1. neg-mul-174.2%

        \[\leadsto \color{blue}{\left(-im\right)} \cdot im \]
    10. Simplified74.2%

      \[\leadsto \color{blue}{\left(-im\right)} \cdot im \]

    if 2.0000000000000001e-61 < (*.f64 im im)

    1. Initial program 88.2%

      \[re \cdot re - im \cdot im \]
    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. sub-neg100.0%

        \[\leadsto \left(re + im\right) \cdot \color{blue}{\left(re + \left(-im\right)\right)} \]
      3. add-sqr-sqrt51.8%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \]
      4. sqrt-unprod61.5%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{\left(-im\right) \cdot \left(-im\right)}}\right) \]
      5. sqr-neg61.5%

        \[\leadsto \left(re + im\right) \cdot \left(re + \sqrt{\color{blue}{im \cdot im}}\right) \]
      6. sqrt-prod11.9%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \]
      7. add-sqr-sqrt26.8%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{im}\right) \]
    4. Applied egg-rr26.8%

      \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re + im\right)} \]
    5. Step-by-step derivation
      1. add-sqr-sqrt11.9%

        \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \cdot \left(re + im\right) \]
      2. sqrt-prod61.5%

        \[\leadsto \left(re + \color{blue}{\sqrt{im \cdot im}}\right) \cdot \left(re + im\right) \]
      3. add-sqr-sqrt11.9%

        \[\leadsto \left(re + \sqrt{im \cdot \color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)}}\right) \cdot \left(re + im\right) \]
      4. add-sqr-sqrt11.9%

        \[\leadsto \left(re + \sqrt{\color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)} \cdot \left(\sqrt{im} \cdot \sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      5. sqr-neg11.9%

        \[\leadsto \left(re + \sqrt{\left(\sqrt{im} \cdot \sqrt{im}\right) \cdot \color{blue}{\left(\left(-\sqrt{im}\right) \cdot \left(-\sqrt{im}\right)\right)}}\right) \cdot \left(re + im\right) \]
      6. swap-sqr11.9%

        \[\leadsto \left(re + \sqrt{\color{blue}{\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)}}\right) \cdot \left(re + im\right) \]
      7. sqrt-unprod0.0%

        \[\leadsto \left(re + \color{blue}{\sqrt{\sqrt{im} \cdot \left(-\sqrt{im}\right)} \cdot \sqrt{\sqrt{im} \cdot \left(-\sqrt{im}\right)}}\right) \cdot \left(re + im\right) \]
      8. add-sqr-sqrt47.9%

        \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \left(-\sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      9. distribute-rgt-neg-out47.9%

        \[\leadsto \left(re + \color{blue}{\left(-\sqrt{im} \cdot \sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      10. add-sqr-sqrt100.0%

        \[\leadsto \left(re + \left(-\color{blue}{im}\right)\right) \cdot \left(re + im\right) \]
      11. sub-neg100.0%

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

      \[\leadsto \color{blue}{\left(re - im\right)} \cdot \left(re + im\right) \]
    7. Taylor expanded in re around 0 78.8%

      \[\leadsto \left(re - im\right) \cdot \color{blue}{im} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification84.3%

    \[\leadsto \begin{array}{l} \mathbf{if}\;im \cdot im \leq 2 \cdot 10^{-185}:\\ \;\;\;\;re \cdot re\\ \mathbf{elif}\;im \cdot im \leq 2 \cdot 10^{-133}:\\ \;\;\;\;im \cdot \left(-im\right)\\ \mathbf{elif}\;im \cdot im \leq 2 \cdot 10^{-61}:\\ \;\;\;\;re \cdot re\\ \mathbf{else}:\\ \;\;\;\;im \cdot \left(re - im\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 76.5% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;re \cdot re \leq 6 \cdot 10^{-72} \lor \neg \left(re \cdot re \leq 1.5 \cdot 10^{+61}\right) \land re \cdot re \leq 10^{+167}:\\ \;\;\;\;im \cdot \left(-im\right)\\ \mathbf{else}:\\ \;\;\;\;re \cdot re\\ \end{array} \end{array} \]
(FPCore re_sqr (re im)
 :precision binary64
 (if (or (<= (* re re) 6e-72)
         (and (not (<= (* re re) 1.5e+61)) (<= (* re re) 1e+167)))
   (* im (- im))
   (* re re)))
double re_sqr(double re, double im) {
	double tmp;
	if (((re * re) <= 6e-72) || (!((re * re) <= 1.5e+61) && ((re * re) <= 1e+167))) {
		tmp = im * -im;
	} else {
		tmp = re * re;
	}
	return tmp;
}
real(8) function re_sqr(re, im)
    real(8), intent (in) :: re
    real(8), intent (in) :: im
    real(8) :: tmp
    if (((re * re) <= 6d-72) .or. (.not. ((re * re) <= 1.5d+61)) .and. ((re * re) <= 1d+167)) then
        tmp = im * -im
    else
        tmp = re * re
    end if
    re_sqr = tmp
end function
public static double re_sqr(double re, double im) {
	double tmp;
	if (((re * re) <= 6e-72) || (!((re * re) <= 1.5e+61) && ((re * re) <= 1e+167))) {
		tmp = im * -im;
	} else {
		tmp = re * re;
	}
	return tmp;
}
def re_sqr(re, im):
	tmp = 0
	if ((re * re) <= 6e-72) or (not ((re * re) <= 1.5e+61) and ((re * re) <= 1e+167)):
		tmp = im * -im
	else:
		tmp = re * re
	return tmp
function re_sqr(re, im)
	tmp = 0.0
	if ((Float64(re * re) <= 6e-72) || (!(Float64(re * re) <= 1.5e+61) && (Float64(re * re) <= 1e+167)))
		tmp = Float64(im * Float64(-im));
	else
		tmp = Float64(re * re);
	end
	return tmp
end
function tmp_2 = re_sqr(re, im)
	tmp = 0.0;
	if (((re * re) <= 6e-72) || (~(((re * re) <= 1.5e+61)) && ((re * re) <= 1e+167)))
		tmp = im * -im;
	else
		tmp = re * re;
	end
	tmp_2 = tmp;
end
re$95$sqr[re_, im_] := If[Or[LessEqual[N[(re * re), $MachinePrecision], 6e-72], And[N[Not[LessEqual[N[(re * re), $MachinePrecision], 1.5e+61]], $MachinePrecision], LessEqual[N[(re * re), $MachinePrecision], 1e+167]]], N[(im * (-im)), $MachinePrecision], N[(re * re), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;re \cdot re \leq 6 \cdot 10^{-72} \lor \neg \left(re \cdot re \leq 1.5 \cdot 10^{+61}\right) \land re \cdot re \leq 10^{+167}:\\
\;\;\;\;im \cdot \left(-im\right)\\

\mathbf{else}:\\
\;\;\;\;re \cdot re\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 re re) < 6e-72 or 1.5e61 < (*.f64 re re) < 1e167

    1. Initial program 100.0%

      \[re \cdot re - im \cdot im \]
    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. sub-neg100.0%

        \[\leadsto \left(re + im\right) \cdot \color{blue}{\left(re + \left(-im\right)\right)} \]
      3. add-sqr-sqrt46.1%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \]
      4. sqrt-unprod65.1%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{\left(-im\right) \cdot \left(-im\right)}}\right) \]
      5. sqr-neg65.1%

        \[\leadsto \left(re + im\right) \cdot \left(re + \sqrt{\color{blue}{im \cdot im}}\right) \]
      6. sqrt-prod18.8%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \]
      7. add-sqr-sqrt29.9%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{im}\right) \]
    4. Applied egg-rr29.9%

      \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re + im\right)} \]
    5. Step-by-step derivation
      1. add-sqr-sqrt18.8%

        \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \cdot \left(re + im\right) \]
      2. sqrt-prod65.1%

        \[\leadsto \left(re + \color{blue}{\sqrt{im \cdot im}}\right) \cdot \left(re + im\right) \]
      3. add-sqr-sqrt18.8%

        \[\leadsto \left(re + \sqrt{im \cdot \color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)}}\right) \cdot \left(re + im\right) \]
      4. add-sqr-sqrt18.8%

        \[\leadsto \left(re + \sqrt{\color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)} \cdot \left(\sqrt{im} \cdot \sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      5. sqr-neg18.8%

        \[\leadsto \left(re + \sqrt{\left(\sqrt{im} \cdot \sqrt{im}\right) \cdot \color{blue}{\left(\left(-\sqrt{im}\right) \cdot \left(-\sqrt{im}\right)\right)}}\right) \cdot \left(re + im\right) \]
      6. swap-sqr18.8%

        \[\leadsto \left(re + \sqrt{\color{blue}{\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)}}\right) \cdot \left(re + im\right) \]
      7. sqrt-unprod0.0%

        \[\leadsto \left(re + \color{blue}{\sqrt{\sqrt{im} \cdot \left(-\sqrt{im}\right)} \cdot \sqrt{\sqrt{im} \cdot \left(-\sqrt{im}\right)}}\right) \cdot \left(re + im\right) \]
      8. add-sqr-sqrt53.5%

        \[\leadsto \left(re + \color{blue}{\sqrt{im} \cdot \left(-\sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      9. distribute-rgt-neg-out53.5%

        \[\leadsto \left(re + \color{blue}{\left(-\sqrt{im} \cdot \sqrt{im}\right)}\right) \cdot \left(re + im\right) \]
      10. add-sqr-sqrt100.0%

        \[\leadsto \left(re + \left(-\color{blue}{im}\right)\right) \cdot \left(re + im\right) \]
      11. sub-neg100.0%

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

      \[\leadsto \color{blue}{\left(re - im\right)} \cdot \left(re + im\right) \]
    7. Taylor expanded in re around 0 83.2%

      \[\leadsto \left(re - im\right) \cdot \color{blue}{im} \]
    8. Taylor expanded in re around 0 83.7%

      \[\leadsto \color{blue}{\left(-1 \cdot im\right)} \cdot im \]
    9. Step-by-step derivation
      1. neg-mul-183.7%

        \[\leadsto \color{blue}{\left(-im\right)} \cdot im \]
    10. Simplified83.7%

      \[\leadsto \color{blue}{\left(-im\right)} \cdot im \]

    if 6e-72 < (*.f64 re re) < 1.5e61 or 1e167 < (*.f64 re re)

    1. Initial program 87.7%

      \[re \cdot re - im \cdot im \]
    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. sub-neg100.0%

        \[\leadsto \left(re + im\right) \cdot \color{blue}{\left(re + \left(-im\right)\right)} \]
      3. add-sqr-sqrt50.8%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \]
      4. sqrt-unprod86.9%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{\left(-im\right) \cdot \left(-im\right)}}\right) \]
      5. sqr-neg86.9%

        \[\leadsto \left(re + im\right) \cdot \left(re + \sqrt{\color{blue}{im \cdot im}}\right) \]
      6. sqrt-prod38.5%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \]
      7. add-sqr-sqrt83.0%

        \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{im}\right) \]
    4. Applied egg-rr83.0%

      \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re + im\right)} \]
    5. Taylor expanded in re around inf 89.2%

      \[\leadsto \left(re + im\right) \cdot \color{blue}{re} \]
    6. Taylor expanded in re around inf 83.7%

      \[\leadsto \color{blue}{re} \cdot re \]
  3. Recombined 2 regimes into one program.
  4. Final simplification83.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;re \cdot re \leq 6 \cdot 10^{-72} \lor \neg \left(re \cdot re \leq 1.5 \cdot 10^{+61}\right) \land re \cdot re \leq 10^{+167}:\\ \;\;\;\;im \cdot \left(-im\right)\\ \mathbf{else}:\\ \;\;\;\;re \cdot re\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 54.0% accurate, 2.3× speedup?

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

\\
re \cdot re
\end{array}
Derivation
  1. Initial program 94.1%

    \[re \cdot re - im \cdot im \]
  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. sub-neg100.0%

      \[\leadsto \left(re + im\right) \cdot \color{blue}{\left(re + \left(-im\right)\right)} \]
    3. add-sqr-sqrt48.3%

      \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{-im} \cdot \sqrt{-im}}\right) \]
    4. sqrt-unprod75.5%

      \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{\left(-im\right) \cdot \left(-im\right)}}\right) \]
    5. sqr-neg75.5%

      \[\leadsto \left(re + im\right) \cdot \left(re + \sqrt{\color{blue}{im \cdot im}}\right) \]
    6. sqrt-prod28.2%

      \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{\sqrt{im} \cdot \sqrt{im}}\right) \]
    7. add-sqr-sqrt55.2%

      \[\leadsto \left(re + im\right) \cdot \left(re + \color{blue}{im}\right) \]
  4. Applied egg-rr55.2%

    \[\leadsto \color{blue}{\left(re + im\right) \cdot \left(re + im\right)} \]
  5. Taylor expanded in re around inf 59.1%

    \[\leadsto \left(re + im\right) \cdot \color{blue}{re} \]
  6. Taylor expanded in re around inf 56.1%

    \[\leadsto \color{blue}{re} \cdot re \]
  7. Add Preprocessing

Alternative 5: 11.3% accurate, 2.3× speedup?

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

\\
im \cdot im
\end{array}
Derivation
  1. Initial program 94.1%

    \[re \cdot re - im \cdot im \]
  2. Add Preprocessing
  3. Taylor expanded in re around 0 52.1%

    \[\leadsto \color{blue}{-1 \cdot {im}^{2}} \]
  4. Step-by-step derivation
    1. neg-mul-152.1%

      \[\leadsto \color{blue}{-{im}^{2}} \]
  5. Simplified52.1%

    \[\leadsto \color{blue}{-{im}^{2}} \]
  6. Step-by-step derivation
    1. unpow252.1%

      \[\leadsto -\color{blue}{im \cdot im} \]
    2. add-sqr-sqrt28.5%

      \[\leadsto -im \cdot \color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)} \]
    3. associate-*r*28.5%

      \[\leadsto -\color{blue}{\left(im \cdot \sqrt{im}\right) \cdot \sqrt{im}} \]
    4. distribute-rgt-neg-out28.5%

      \[\leadsto \color{blue}{\left(im \cdot \sqrt{im}\right) \cdot \left(-\sqrt{im}\right)} \]
    5. associate-*r*28.5%

      \[\leadsto \color{blue}{im \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)} \]
    6. add-sqr-sqrt4.7%

      \[\leadsto \color{blue}{\sqrt{im \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)} \cdot \sqrt{im \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)}} \]
    7. sqrt-unprod7.6%

      \[\leadsto \color{blue}{\sqrt{\left(im \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)\right) \cdot \left(im \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)\right)}} \]
    8. swap-sqr7.6%

      \[\leadsto \sqrt{\color{blue}{\left(im \cdot im\right) \cdot \left(\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)\right)}} \]
    9. unpow27.6%

      \[\leadsto \sqrt{\color{blue}{{im}^{2}} \cdot \left(\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)\right)} \]
    10. metadata-eval7.6%

      \[\leadsto \sqrt{{im}^{\color{blue}{\left(0.3333333333333333 \cdot 6\right)}} \cdot \left(\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)\right)} \]
    11. pow-pow7.6%

      \[\leadsto \sqrt{\color{blue}{{\left({im}^{0.3333333333333333}\right)}^{6}} \cdot \left(\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)\right)} \]
    12. pow1/37.6%

      \[\leadsto \sqrt{{\color{blue}{\left(\sqrt[3]{im}\right)}}^{6} \cdot \left(\left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right) \cdot \left(\sqrt{im} \cdot \left(-\sqrt{im}\right)\right)\right)} \]
    13. swap-sqr7.6%

      \[\leadsto \sqrt{{\left(\sqrt[3]{im}\right)}^{6} \cdot \color{blue}{\left(\left(\sqrt{im} \cdot \sqrt{im}\right) \cdot \left(\left(-\sqrt{im}\right) \cdot \left(-\sqrt{im}\right)\right)\right)}} \]
    14. sqr-neg7.6%

      \[\leadsto \sqrt{{\left(\sqrt[3]{im}\right)}^{6} \cdot \left(\left(\sqrt{im} \cdot \sqrt{im}\right) \cdot \color{blue}{\left(\sqrt{im} \cdot \sqrt{im}\right)}\right)} \]
    15. add-sqr-sqrt7.6%

      \[\leadsto \sqrt{{\left(\sqrt[3]{im}\right)}^{6} \cdot \left(\color{blue}{im} \cdot \left(\sqrt{im} \cdot \sqrt{im}\right)\right)} \]
    16. add-sqr-sqrt14.8%

      \[\leadsto \sqrt{{\left(\sqrt[3]{im}\right)}^{6} \cdot \left(im \cdot \color{blue}{im}\right)} \]
    17. unpow214.8%

      \[\leadsto \sqrt{{\left(\sqrt[3]{im}\right)}^{6} \cdot \color{blue}{{im}^{2}}} \]
    18. metadata-eval14.8%

      \[\leadsto \sqrt{{\left(\sqrt[3]{im}\right)}^{6} \cdot {im}^{\color{blue}{\left(0.3333333333333333 \cdot 6\right)}}} \]
    19. pow-pow7.6%

      \[\leadsto \sqrt{{\left(\sqrt[3]{im}\right)}^{6} \cdot \color{blue}{{\left({im}^{0.3333333333333333}\right)}^{6}}} \]
    20. pow1/314.8%

      \[\leadsto \sqrt{{\left(\sqrt[3]{im}\right)}^{6} \cdot {\color{blue}{\left(\sqrt[3]{im}\right)}}^{6}} \]
  7. Applied egg-rr12.5%

    \[\leadsto \color{blue}{im \cdot im} \]
  8. Add Preprocessing

Reproduce

?
herbie shell --seed 2024110 
(FPCore re_sqr (re im)
  :name "math.square on complex, real part"
  :precision binary64
  (- (* re re) (* im im)))