Numeric.Log:$cexpm1 from log-domain-0.10.2.1, B

Percentage Accurate: 100.0% → 100.0%
Time: 1.9s
Alternatives: 6
Speedup: 0.1×

Specification

?
\[\begin{array}{l} \\ \left(x \cdot y + x\right) + y \end{array} \]
(FPCore (x y) :precision binary64 (+ (+ (* x y) x) y))
double code(double x, double y) {
	return ((x * y) + x) + y;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = ((x * y) + x) + y
end function
public static double code(double x, double y) {
	return ((x * y) + x) + y;
}
def code(x, y):
	return ((x * y) + x) + y
function code(x, y)
	return Float64(Float64(Float64(x * y) + x) + y)
end
function tmp = code(x, y)
	tmp = ((x * y) + x) + y;
end
code[x_, y_] := N[(N[(N[(x * y), $MachinePrecision] + x), $MachinePrecision] + y), $MachinePrecision]
\begin{array}{l}

\\
\left(x \cdot y + x\right) + y
\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 6 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: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(x \cdot y + x\right) + y \end{array} \]
(FPCore (x y) :precision binary64 (+ (+ (* x y) x) y))
double code(double x, double y) {
	return ((x * y) + x) + y;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = ((x * y) + x) + y
end function
public static double code(double x, double y) {
	return ((x * y) + x) + y;
}
def code(x, y):
	return ((x * y) + x) + y
function code(x, y)
	return Float64(Float64(Float64(x * y) + x) + y)
end
function tmp = code(x, y)
	tmp = ((x * y) + x) + y;
end
code[x_, y_] := N[(N[(N[(x * y), $MachinePrecision] + x), $MachinePrecision] + y), $MachinePrecision]
\begin{array}{l}

\\
\left(x \cdot y + x\right) + y
\end{array}

Alternative 1: 100.0% accurate, 0.1× speedup?

\[\begin{array}{l} \\ y + \mathsf{fma}\left(x, y, x\right) \end{array} \]
(FPCore (x y) :precision binary64 (+ y (fma x y x)))
double code(double x, double y) {
	return y + fma(x, y, x);
}
function code(x, y)
	return Float64(y + fma(x, y, x))
end
code[x_, y_] := N[(y + N[(x * y + x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
y + \mathsf{fma}\left(x, y, x\right)
\end{array}
Derivation
  1. Initial program 100.0%

    \[\left(x \cdot y + x\right) + y \]
  2. Step-by-step derivation
    1. +-commutative100.0%

      \[\leadsto \color{blue}{y + \left(x \cdot y + x\right)} \]
    2. fma-def100.0%

      \[\leadsto y + \color{blue}{\mathsf{fma}\left(x, y, x\right)} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{y + \mathsf{fma}\left(x, y, x\right)} \]
  4. Final simplification100.0%

    \[\leadsto y + \mathsf{fma}\left(x, y, x\right) \]

Alternative 2: 74.4% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1.45 \cdot 10^{+203}:\\ \;\;\;\;y \cdot x\\ \mathbf{elif}\;x \leq -1 \cdot 10^{+100} \lor \neg \left(x \leq -9.2 \cdot 10^{+79}\right) \land x \leq 10500:\\ \;\;\;\;y + x\\ \mathbf{else}:\\ \;\;\;\;y \cdot x\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= x -1.45e+203)
   (* y x)
   (if (or (<= x -1e+100) (and (not (<= x -9.2e+79)) (<= x 10500.0)))
     (+ y x)
     (* y x))))
double code(double x, double y) {
	double tmp;
	if (x <= -1.45e+203) {
		tmp = y * x;
	} else if ((x <= -1e+100) || (!(x <= -9.2e+79) && (x <= 10500.0))) {
		tmp = y + x;
	} else {
		tmp = y * x;
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: tmp
    if (x <= (-1.45d+203)) then
        tmp = y * x
    else if ((x <= (-1d+100)) .or. (.not. (x <= (-9.2d+79))) .and. (x <= 10500.0d0)) then
        tmp = y + x
    else
        tmp = y * x
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double tmp;
	if (x <= -1.45e+203) {
		tmp = y * x;
	} else if ((x <= -1e+100) || (!(x <= -9.2e+79) && (x <= 10500.0))) {
		tmp = y + x;
	} else {
		tmp = y * x;
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if x <= -1.45e+203:
		tmp = y * x
	elif (x <= -1e+100) or (not (x <= -9.2e+79) and (x <= 10500.0)):
		tmp = y + x
	else:
		tmp = y * x
	return tmp
function code(x, y)
	tmp = 0.0
	if (x <= -1.45e+203)
		tmp = Float64(y * x);
	elseif ((x <= -1e+100) || (!(x <= -9.2e+79) && (x <= 10500.0)))
		tmp = Float64(y + x);
	else
		tmp = Float64(y * x);
	end
	return tmp
end
function tmp_2 = code(x, y)
	tmp = 0.0;
	if (x <= -1.45e+203)
		tmp = y * x;
	elseif ((x <= -1e+100) || (~((x <= -9.2e+79)) && (x <= 10500.0)))
		tmp = y + x;
	else
		tmp = y * x;
	end
	tmp_2 = tmp;
end
code[x_, y_] := If[LessEqual[x, -1.45e+203], N[(y * x), $MachinePrecision], If[Or[LessEqual[x, -1e+100], And[N[Not[LessEqual[x, -9.2e+79]], $MachinePrecision], LessEqual[x, 10500.0]]], N[(y + x), $MachinePrecision], N[(y * x), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.45 \cdot 10^{+203}:\\
\;\;\;\;y \cdot x\\

\mathbf{elif}\;x \leq -1 \cdot 10^{+100} \lor \neg \left(x \leq -9.2 \cdot 10^{+79}\right) \land x \leq 10500:\\
\;\;\;\;y + x\\

\mathbf{else}:\\
\;\;\;\;y \cdot x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -1.45000000000000005e203 or -1.00000000000000002e100 < x < -9.2000000000000002e79 or 10500 < x

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Taylor expanded in y around inf 60.9%

      \[\leadsto \color{blue}{x \cdot y} + y \]
    3. Taylor expanded in x around inf 59.7%

      \[\leadsto \color{blue}{x \cdot y} \]
    4. Step-by-step derivation
      1. *-commutative59.7%

        \[\leadsto \color{blue}{y \cdot x} \]
    5. Simplified59.7%

      \[\leadsto \color{blue}{y \cdot x} \]

    if -1.45000000000000005e203 < x < -1.00000000000000002e100 or -9.2000000000000002e79 < x < 10500

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Taylor expanded in y around 0 90.5%

      \[\leadsto \color{blue}{x} + y \]
  3. Recombined 2 regimes into one program.
  4. Final simplification80.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1.45 \cdot 10^{+203}:\\ \;\;\;\;y \cdot x\\ \mathbf{elif}\;x \leq -1 \cdot 10^{+100} \lor \neg \left(x \leq -9.2 \cdot 10^{+79}\right) \land x \leq 10500:\\ \;\;\;\;y + x\\ \mathbf{else}:\\ \;\;\;\;y \cdot x\\ \end{array} \]

Alternative 3: 87.1% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -940:\\ \;\;\;\;y \cdot x\\ \mathbf{elif}\;y \leq 0.125:\\ \;\;\;\;y + x\\ \mathbf{else}:\\ \;\;\;\;y + y \cdot x\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -940.0) (* y x) (if (<= y 0.125) (+ y x) (+ y (* y x)))))
double code(double x, double y) {
	double tmp;
	if (y <= -940.0) {
		tmp = y * x;
	} else if (y <= 0.125) {
		tmp = y + x;
	} else {
		tmp = y + (y * x);
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: tmp
    if (y <= (-940.0d0)) then
        tmp = y * x
    else if (y <= 0.125d0) then
        tmp = y + x
    else
        tmp = y + (y * x)
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double tmp;
	if (y <= -940.0) {
		tmp = y * x;
	} else if (y <= 0.125) {
		tmp = y + x;
	} else {
		tmp = y + (y * x);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if y <= -940.0:
		tmp = y * x
	elif y <= 0.125:
		tmp = y + x
	else:
		tmp = y + (y * x)
	return tmp
function code(x, y)
	tmp = 0.0
	if (y <= -940.0)
		tmp = Float64(y * x);
	elseif (y <= 0.125)
		tmp = Float64(y + x);
	else
		tmp = Float64(y + Float64(y * x));
	end
	return tmp
end
function tmp_2 = code(x, y)
	tmp = 0.0;
	if (y <= -940.0)
		tmp = y * x;
	elseif (y <= 0.125)
		tmp = y + x;
	else
		tmp = y + (y * x);
	end
	tmp_2 = tmp;
end
code[x_, y_] := If[LessEqual[y, -940.0], N[(y * x), $MachinePrecision], If[LessEqual[y, 0.125], N[(y + x), $MachinePrecision], N[(y + N[(y * x), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -940:\\
\;\;\;\;y \cdot x\\

\mathbf{elif}\;y \leq 0.125:\\
\;\;\;\;y + x\\

\mathbf{else}:\\
\;\;\;\;y + y \cdot x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -940

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Taylor expanded in y around inf 98.9%

      \[\leadsto \color{blue}{x \cdot y} + y \]
    3. Taylor expanded in x around inf 50.1%

      \[\leadsto \color{blue}{x \cdot y} \]
    4. Step-by-step derivation
      1. *-commutative50.1%

        \[\leadsto \color{blue}{y \cdot x} \]
    5. Simplified50.1%

      \[\leadsto \color{blue}{y \cdot x} \]

    if -940 < y < 0.125

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Taylor expanded in y around 0 99.1%

      \[\leadsto \color{blue}{x} + y \]

    if 0.125 < y

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Taylor expanded in y around inf 98.2%

      \[\leadsto \color{blue}{x \cdot y} + y \]
  3. Recombined 3 regimes into one program.
  4. Final simplification87.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -940:\\ \;\;\;\;y \cdot x\\ \mathbf{elif}\;y \leq 0.125:\\ \;\;\;\;y + x\\ \mathbf{else}:\\ \;\;\;\;y + y \cdot x\\ \end{array} \]

Alternative 4: 61.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -6.8 \cdot 10^{-10}:\\ \;\;\;\;y \cdot x\\ \mathbf{elif}\;x \leq 1:\\ \;\;\;\;y\\ \mathbf{else}:\\ \;\;\;\;y \cdot x\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= x -6.8e-10) (* y x) (if (<= x 1.0) y (* y x))))
double code(double x, double y) {
	double tmp;
	if (x <= -6.8e-10) {
		tmp = y * x;
	} else if (x <= 1.0) {
		tmp = y;
	} else {
		tmp = y * x;
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: tmp
    if (x <= (-6.8d-10)) then
        tmp = y * x
    else if (x <= 1.0d0) then
        tmp = y
    else
        tmp = y * x
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double tmp;
	if (x <= -6.8e-10) {
		tmp = y * x;
	} else if (x <= 1.0) {
		tmp = y;
	} else {
		tmp = y * x;
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if x <= -6.8e-10:
		tmp = y * x
	elif x <= 1.0:
		tmp = y
	else:
		tmp = y * x
	return tmp
function code(x, y)
	tmp = 0.0
	if (x <= -6.8e-10)
		tmp = Float64(y * x);
	elseif (x <= 1.0)
		tmp = y;
	else
		tmp = Float64(y * x);
	end
	return tmp
end
function tmp_2 = code(x, y)
	tmp = 0.0;
	if (x <= -6.8e-10)
		tmp = y * x;
	elseif (x <= 1.0)
		tmp = y;
	else
		tmp = y * x;
	end
	tmp_2 = tmp;
end
code[x_, y_] := If[LessEqual[x, -6.8e-10], N[(y * x), $MachinePrecision], If[LessEqual[x, 1.0], y, N[(y * x), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq -6.8 \cdot 10^{-10}:\\
\;\;\;\;y \cdot x\\

\mathbf{elif}\;x \leq 1:\\
\;\;\;\;y\\

\mathbf{else}:\\
\;\;\;\;y \cdot x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -6.8000000000000003e-10 or 1 < x

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Taylor expanded in y around inf 53.7%

      \[\leadsto \color{blue}{x \cdot y} + y \]
    3. Taylor expanded in x around inf 51.8%

      \[\leadsto \color{blue}{x \cdot y} \]
    4. Step-by-step derivation
      1. *-commutative51.8%

        \[\leadsto \color{blue}{y \cdot x} \]
    5. Simplified51.8%

      \[\leadsto \color{blue}{y \cdot x} \]

    if -6.8000000000000003e-10 < x < 1

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Taylor expanded in y around inf 74.0%

      \[\leadsto \color{blue}{x \cdot y} + y \]
    3. Taylor expanded in x around 0 73.4%

      \[\leadsto \color{blue}{y} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification62.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -6.8 \cdot 10^{-10}:\\ \;\;\;\;y \cdot x\\ \mathbf{elif}\;x \leq 1:\\ \;\;\;\;y\\ \mathbf{else}:\\ \;\;\;\;y \cdot x\\ \end{array} \]

Alternative 5: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ y + x \cdot \left(y + 1\right) \end{array} \]
(FPCore (x y) :precision binary64 (+ y (* x (+ y 1.0))))
double code(double x, double y) {
	return y + (x * (y + 1.0));
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = y + (x * (y + 1.0d0))
end function
public static double code(double x, double y) {
	return y + (x * (y + 1.0));
}
def code(x, y):
	return y + (x * (y + 1.0))
function code(x, y)
	return Float64(y + Float64(x * Float64(y + 1.0)))
end
function tmp = code(x, y)
	tmp = y + (x * (y + 1.0));
end
code[x_, y_] := N[(y + N[(x * N[(y + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
y + x \cdot \left(y + 1\right)
\end{array}
Derivation
  1. Initial program 100.0%

    \[\left(x \cdot y + x\right) + y \]
  2. Step-by-step derivation
    1. *-commutative100.0%

      \[\leadsto \left(\color{blue}{y \cdot x} + x\right) + y \]
    2. distribute-lft1-in100.0%

      \[\leadsto \color{blue}{\left(y + 1\right) \cdot x} + y \]
  3. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\left(y + 1\right) \cdot x} + y \]
  4. Final simplification100.0%

    \[\leadsto y + x \cdot \left(y + 1\right) \]

Alternative 6: 38.9% accurate, 7.0× speedup?

\[\begin{array}{l} \\ y \end{array} \]
(FPCore (x y) :precision binary64 y)
double code(double x, double y) {
	return y;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = y
end function
public static double code(double x, double y) {
	return y;
}
def code(x, y):
	return y
function code(x, y)
	return y
end
function tmp = code(x, y)
	tmp = y;
end
code[x_, y_] := y
\begin{array}{l}

\\
y
\end{array}
Derivation
  1. Initial program 100.0%

    \[\left(x \cdot y + x\right) + y \]
  2. Taylor expanded in y around inf 63.8%

    \[\leadsto \color{blue}{x \cdot y} + y \]
  3. Taylor expanded in x around 0 38.4%

    \[\leadsto \color{blue}{y} \]
  4. Final simplification38.4%

    \[\leadsto y \]

Reproduce

?
herbie shell --seed 2023271 
(FPCore (x y)
  :name "Numeric.Log:$cexpm1 from log-domain-0.10.2.1, B"
  :precision binary64
  (+ (+ (* x y) x) y))