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

Percentage Accurate: 100.0% → 100.0%
Time: 9.0s
Alternatives: 5
Speedup: 1.2×

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 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: 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, 1.2× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(y + 1, x, y\right) \end{array} \]
(FPCore (x y) :precision binary64 (fma (+ y 1.0) x y))
double code(double x, double y) {
	return fma((y + 1.0), x, y);
}
function code(x, y)
	return fma(Float64(y + 1.0), x, y)
end
code[x_, y_] := N[(N[(y + 1.0), $MachinePrecision] * x + y), $MachinePrecision]
\begin{array}{l}

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

    \[\left(x \cdot y + x\right) + y \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \left(\color{blue}{y \cdot x} + x\right) + y \]
    2. distribute-lft1-inN/A

      \[\leadsto \color{blue}{\left(y + 1\right) \cdot x} + y \]
    3. lower-fma.f64N/A

      \[\leadsto \color{blue}{\mathsf{fma}\left(y + 1, x, y\right)} \]
    4. lower-+.f64100.0

      \[\leadsto \mathsf{fma}\left(\color{blue}{y + 1}, x, y\right) \]
  4. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\mathsf{fma}\left(y + 1, x, y\right)} \]
  5. Add Preprocessing

Alternative 2: 84.5% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := y + \left(x + y \cdot x\right)\\ \mathbf{if}\;t\_0 \leq -\infty:\\ \;\;\;\;y \cdot x\\ \mathbf{elif}\;t\_0 \leq 2 \cdot 10^{+245}:\\ \;\;\;\;y + x\\ \mathbf{else}:\\ \;\;\;\;y \cdot x\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (let* ((t_0 (+ y (+ x (* y x)))))
   (if (<= t_0 (- INFINITY)) (* y x) (if (<= t_0 2e+245) (+ y x) (* y x)))))
double code(double x, double y) {
	double t_0 = y + (x + (y * x));
	double tmp;
	if (t_0 <= -((double) INFINITY)) {
		tmp = y * x;
	} else if (t_0 <= 2e+245) {
		tmp = y + x;
	} else {
		tmp = y * x;
	}
	return tmp;
}
public static double code(double x, double y) {
	double t_0 = y + (x + (y * x));
	double tmp;
	if (t_0 <= -Double.POSITIVE_INFINITY) {
		tmp = y * x;
	} else if (t_0 <= 2e+245) {
		tmp = y + x;
	} else {
		tmp = y * x;
	}
	return tmp;
}
def code(x, y):
	t_0 = y + (x + (y * x))
	tmp = 0
	if t_0 <= -math.inf:
		tmp = y * x
	elif t_0 <= 2e+245:
		tmp = y + x
	else:
		tmp = y * x
	return tmp
function code(x, y)
	t_0 = Float64(y + Float64(x + Float64(y * x)))
	tmp = 0.0
	if (t_0 <= Float64(-Inf))
		tmp = Float64(y * x);
	elseif (t_0 <= 2e+245)
		tmp = Float64(y + x);
	else
		tmp = Float64(y * x);
	end
	return tmp
end
function tmp_2 = code(x, y)
	t_0 = y + (x + (y * x));
	tmp = 0.0;
	if (t_0 <= -Inf)
		tmp = y * x;
	elseif (t_0 <= 2e+245)
		tmp = y + x;
	else
		tmp = y * x;
	end
	tmp_2 = tmp;
end
code[x_, y_] := Block[{t$95$0 = N[(y + N[(x + N[(y * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, (-Infinity)], N[(y * x), $MachinePrecision], If[LessEqual[t$95$0, 2e+245], N[(y + x), $MachinePrecision], N[(y * x), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := y + \left(x + y \cdot x\right)\\
\mathbf{if}\;t\_0 \leq -\infty:\\
\;\;\;\;y \cdot x\\

\mathbf{elif}\;t\_0 \leq 2 \cdot 10^{+245}:\\
\;\;\;\;y + x\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (+.f64 (+.f64 (*.f64 x y) x) y) < -inf.0 or 2.00000000000000009e245 < (+.f64 (+.f64 (*.f64 x y) x) y)

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Add Preprocessing
    3. Taylor expanded in x around inf

      \[\leadsto \color{blue}{x \cdot \left(1 + y\right)} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto x \cdot \color{blue}{\left(y + 1\right)} \]
      2. distribute-lft-inN/A

        \[\leadsto \color{blue}{x \cdot y + x \cdot 1} \]
      3. *-rgt-identityN/A

        \[\leadsto x \cdot y + \color{blue}{x} \]
      4. lower-fma.f6488.4

        \[\leadsto \color{blue}{\mathsf{fma}\left(x, y, x\right)} \]
    5. Simplified88.4%

      \[\leadsto \color{blue}{\mathsf{fma}\left(x, y, x\right)} \]
    6. Taylor expanded in y around inf

      \[\leadsto \color{blue}{x \cdot y} \]
    7. Step-by-step derivation
      1. lower-*.f6484.2

        \[\leadsto \color{blue}{x \cdot y} \]
    8. Simplified84.2%

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

    if -inf.0 < (+.f64 (+.f64 (*.f64 x y) x) y) < 2.00000000000000009e245

    1. Initial program 100.0%

      \[\left(x \cdot y + x\right) + y \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \left(\color{blue}{y \cdot x} + x\right) + y \]
      2. distribute-lft1-inN/A

        \[\leadsto \color{blue}{\left(y + 1\right) \cdot x} + y \]
      3. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(y + 1, x, y\right)} \]
      4. lower-+.f64100.0

        \[\leadsto \mathsf{fma}\left(\color{blue}{y + 1}, x, y\right) \]
    4. Applied egg-rr100.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(y + 1, x, y\right)} \]
    5. Taylor expanded in y around 0

      \[\leadsto \mathsf{fma}\left(\color{blue}{1}, x, y\right) \]
    6. Step-by-step derivation
      1. Simplified86.5%

        \[\leadsto \mathsf{fma}\left(\color{blue}{1}, x, y\right) \]
      2. Step-by-step derivation
        1. +-commutativeN/A

          \[\leadsto \color{blue}{y + 1 \cdot x} \]
        2. lower-+.f64N/A

          \[\leadsto \color{blue}{y + 1 \cdot x} \]
        3. *-lft-identity86.5

          \[\leadsto y + \color{blue}{x} \]
      3. Applied egg-rr86.5%

        \[\leadsto \color{blue}{y + x} \]
    7. Recombined 2 regimes into one program.
    8. Final simplification86.2%

      \[\leadsto \begin{array}{l} \mathbf{if}\;y + \left(x + y \cdot x\right) \leq -\infty:\\ \;\;\;\;y \cdot x\\ \mathbf{elif}\;y + \left(x + y \cdot x\right) \leq 2 \cdot 10^{+245}:\\ \;\;\;\;y + x\\ \mathbf{else}:\\ \;\;\;\;y \cdot x\\ \end{array} \]
    9. Add Preprocessing

    Alternative 3: 63.5% accurate, 0.5× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y + \left(x + y \cdot x\right) \leq -2 \cdot 10^{-300}:\\ \;\;\;\;\mathsf{fma}\left(x, y, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(x, y, y\right)\\ \end{array} \end{array} \]
    (FPCore (x y)
     :precision binary64
     (if (<= (+ y (+ x (* y x))) -2e-300) (fma x y x) (fma x y y)))
    double code(double x, double y) {
    	double tmp;
    	if ((y + (x + (y * x))) <= -2e-300) {
    		tmp = fma(x, y, x);
    	} else {
    		tmp = fma(x, y, y);
    	}
    	return tmp;
    }
    
    function code(x, y)
    	tmp = 0.0
    	if (Float64(y + Float64(x + Float64(y * x))) <= -2e-300)
    		tmp = fma(x, y, x);
    	else
    		tmp = fma(x, y, y);
    	end
    	return tmp
    end
    
    code[x_, y_] := If[LessEqual[N[(y + N[(x + N[(y * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], -2e-300], N[(x * y + x), $MachinePrecision], N[(x * y + y), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;y + \left(x + y \cdot x\right) \leq -2 \cdot 10^{-300}:\\
    \;\;\;\;\mathsf{fma}\left(x, y, x\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\mathsf{fma}\left(x, y, y\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (+.f64 (+.f64 (*.f64 x y) x) y) < -2.00000000000000005e-300

      1. Initial program 100.0%

        \[\left(x \cdot y + x\right) + y \]
      2. Add Preprocessing
      3. Taylor expanded in x around inf

        \[\leadsto \color{blue}{x \cdot \left(1 + y\right)} \]
      4. Step-by-step derivation
        1. +-commutativeN/A

          \[\leadsto x \cdot \color{blue}{\left(y + 1\right)} \]
        2. distribute-lft-inN/A

          \[\leadsto \color{blue}{x \cdot y + x \cdot 1} \]
        3. *-rgt-identityN/A

          \[\leadsto x \cdot y + \color{blue}{x} \]
        4. lower-fma.f6464.1

          \[\leadsto \color{blue}{\mathsf{fma}\left(x, y, x\right)} \]
      5. Simplified64.1%

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

      if -2.00000000000000005e-300 < (+.f64 (+.f64 (*.f64 x y) x) y)

      1. Initial program 100.0%

        \[\left(x \cdot y + x\right) + y \]
      2. Add Preprocessing
      3. Taylor expanded in y around inf

        \[\leadsto \color{blue}{y \cdot \left(1 + x\right)} \]
      4. Step-by-step derivation
        1. distribute-rgt-inN/A

          \[\leadsto \color{blue}{1 \cdot y + x \cdot y} \]
        2. *-lft-identityN/A

          \[\leadsto \color{blue}{y} + x \cdot y \]
        3. +-commutativeN/A

          \[\leadsto \color{blue}{x \cdot y + y} \]
        4. lower-fma.f6461.1

          \[\leadsto \color{blue}{\mathsf{fma}\left(x, y, y\right)} \]
      5. Simplified61.1%

        \[\leadsto \color{blue}{\mathsf{fma}\left(x, y, y\right)} \]
    3. Recombined 2 regimes into one program.
    4. Final simplification62.8%

      \[\leadsto \begin{array}{l} \mathbf{if}\;y + \left(x + y \cdot x\right) \leq -2 \cdot 10^{-300}:\\ \;\;\;\;\mathsf{fma}\left(x, y, x\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(x, y, y\right)\\ \end{array} \]
    5. Add Preprocessing

    Alternative 4: 98.6% accurate, 0.6× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq -1520000000000:\\ \;\;\;\;\mathsf{fma}\left(x, y, x\right)\\ \mathbf{elif}\;x \leq 1:\\ \;\;\;\;y + x\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(x, y, x\right)\\ \end{array} \end{array} \]
    (FPCore (x y)
     :precision binary64
     (if (<= x -1520000000000.0) (fma x y x) (if (<= x 1.0) (+ y x) (fma x y x))))
    double code(double x, double y) {
    	double tmp;
    	if (x <= -1520000000000.0) {
    		tmp = fma(x, y, x);
    	} else if (x <= 1.0) {
    		tmp = y + x;
    	} else {
    		tmp = fma(x, y, x);
    	}
    	return tmp;
    }
    
    function code(x, y)
    	tmp = 0.0
    	if (x <= -1520000000000.0)
    		tmp = fma(x, y, x);
    	elseif (x <= 1.0)
    		tmp = Float64(y + x);
    	else
    		tmp = fma(x, y, x);
    	end
    	return tmp
    end
    
    code[x_, y_] := If[LessEqual[x, -1520000000000.0], N[(x * y + x), $MachinePrecision], If[LessEqual[x, 1.0], N[(y + x), $MachinePrecision], N[(x * y + x), $MachinePrecision]]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;x \leq -1520000000000:\\
    \;\;\;\;\mathsf{fma}\left(x, y, x\right)\\
    
    \mathbf{elif}\;x \leq 1:\\
    \;\;\;\;y + x\\
    
    \mathbf{else}:\\
    \;\;\;\;\mathsf{fma}\left(x, y, x\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if x < -1.52e12 or 1 < x

      1. Initial program 100.0%

        \[\left(x \cdot y + x\right) + y \]
      2. Add Preprocessing
      3. Taylor expanded in x around inf

        \[\leadsto \color{blue}{x \cdot \left(1 + y\right)} \]
      4. Step-by-step derivation
        1. +-commutativeN/A

          \[\leadsto x \cdot \color{blue}{\left(y + 1\right)} \]
        2. distribute-lft-inN/A

          \[\leadsto \color{blue}{x \cdot y + x \cdot 1} \]
        3. *-rgt-identityN/A

          \[\leadsto x \cdot y + \color{blue}{x} \]
        4. lower-fma.f6499.9

          \[\leadsto \color{blue}{\mathsf{fma}\left(x, y, x\right)} \]
      5. Simplified99.9%

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

      if -1.52e12 < x < 1

      1. Initial program 100.0%

        \[\left(x \cdot y + x\right) + y \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. *-commutativeN/A

          \[\leadsto \left(\color{blue}{y \cdot x} + x\right) + y \]
        2. distribute-lft1-inN/A

          \[\leadsto \color{blue}{\left(y + 1\right) \cdot x} + y \]
        3. lower-fma.f64N/A

          \[\leadsto \color{blue}{\mathsf{fma}\left(y + 1, x, y\right)} \]
        4. lower-+.f64100.0

          \[\leadsto \mathsf{fma}\left(\color{blue}{y + 1}, x, y\right) \]
      4. Applied egg-rr100.0%

        \[\leadsto \color{blue}{\mathsf{fma}\left(y + 1, x, y\right)} \]
      5. Taylor expanded in y around 0

        \[\leadsto \mathsf{fma}\left(\color{blue}{1}, x, y\right) \]
      6. Step-by-step derivation
        1. Simplified98.5%

          \[\leadsto \mathsf{fma}\left(\color{blue}{1}, x, y\right) \]
        2. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \color{blue}{y + 1 \cdot x} \]
          2. lower-+.f64N/A

            \[\leadsto \color{blue}{y + 1 \cdot x} \]
          3. *-lft-identity98.5

            \[\leadsto y + \color{blue}{x} \]
        3. Applied egg-rr98.5%

          \[\leadsto \color{blue}{y + x} \]
      7. Recombined 2 regimes into one program.
      8. Add Preprocessing

      Alternative 5: 75.0% accurate, 3.0× speedup?

      \[\begin{array}{l} \\ y + x \end{array} \]
      (FPCore (x y) :precision binary64 (+ y x))
      double code(double x, double y) {
      	return y + x;
      }
      
      real(8) function code(x, y)
          real(8), intent (in) :: x
          real(8), intent (in) :: y
          code = y + x
      end function
      
      public static double code(double x, double y) {
      	return y + x;
      }
      
      def code(x, y):
      	return y + x
      
      function code(x, y)
      	return Float64(y + x)
      end
      
      function tmp = code(x, y)
      	tmp = y + x;
      end
      
      code[x_, y_] := N[(y + x), $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      y + x
      \end{array}
      
      Derivation
      1. Initial program 100.0%

        \[\left(x \cdot y + x\right) + y \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. *-commutativeN/A

          \[\leadsto \left(\color{blue}{y \cdot x} + x\right) + y \]
        2. distribute-lft1-inN/A

          \[\leadsto \color{blue}{\left(y + 1\right) \cdot x} + y \]
        3. lower-fma.f64N/A

          \[\leadsto \color{blue}{\mathsf{fma}\left(y + 1, x, y\right)} \]
        4. lower-+.f64100.0

          \[\leadsto \mathsf{fma}\left(\color{blue}{y + 1}, x, y\right) \]
      4. Applied egg-rr100.0%

        \[\leadsto \color{blue}{\mathsf{fma}\left(y + 1, x, y\right)} \]
      5. Taylor expanded in y around 0

        \[\leadsto \mathsf{fma}\left(\color{blue}{1}, x, y\right) \]
      6. Step-by-step derivation
        1. Simplified78.9%

          \[\leadsto \mathsf{fma}\left(\color{blue}{1}, x, y\right) \]
        2. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \color{blue}{y + 1 \cdot x} \]
          2. lower-+.f64N/A

            \[\leadsto \color{blue}{y + 1 \cdot x} \]
          3. *-lft-identity78.9

            \[\leadsto y + \color{blue}{x} \]
        3. Applied egg-rr78.9%

          \[\leadsto \color{blue}{y + x} \]
        4. Add Preprocessing

        Reproduce

        ?
        herbie shell --seed 2024207 
        (FPCore (x y)
          :name "Numeric.Log:$cexpm1 from log-domain-0.10.2.1, B"
          :precision binary64
          (+ (+ (* x y) x) y))