xlohi (overflows)

Percentage Accurate: 3.1% → 19.4%
Time: 15.8s
Alternatives: 6
Speedup: 18.0×

Specification

?
\[lo < -1 \cdot 10^{+308} \land hi > 10^{+308}\]
\[\begin{array}{l} \\ \frac{x - lo}{hi - lo} \end{array} \]
(FPCore (lo hi x) :precision binary64 (/ (- x lo) (- hi lo)))
double code(double lo, double hi, double x) {
	return (x - lo) / (hi - lo);
}
real(8) function code(lo, hi, x)
    real(8), intent (in) :: lo
    real(8), intent (in) :: hi
    real(8), intent (in) :: x
    code = (x - lo) / (hi - lo)
end function
public static double code(double lo, double hi, double x) {
	return (x - lo) / (hi - lo);
}
def code(lo, hi, x):
	return (x - lo) / (hi - lo)
function code(lo, hi, x)
	return Float64(Float64(x - lo) / Float64(hi - lo))
end
function tmp = code(lo, hi, x)
	tmp = (x - lo) / (hi - lo);
end
code[lo_, hi_, x_] := N[(N[(x - lo), $MachinePrecision] / N[(hi - lo), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{x - lo}{hi - lo}
\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: 3.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{x - lo}{hi - lo} \end{array} \]
(FPCore (lo hi x) :precision binary64 (/ (- x lo) (- hi lo)))
double code(double lo, double hi, double x) {
	return (x - lo) / (hi - lo);
}
real(8) function code(lo, hi, x)
    real(8), intent (in) :: lo
    real(8), intent (in) :: hi
    real(8), intent (in) :: x
    code = (x - lo) / (hi - lo)
end function
public static double code(double lo, double hi, double x) {
	return (x - lo) / (hi - lo);
}
def code(lo, hi, x):
	return (x - lo) / (hi - lo)
function code(lo, hi, x)
	return Float64(Float64(x - lo) / Float64(hi - lo))
end
function tmp = code(lo, hi, x)
	tmp = (x - lo) / (hi - lo);
end
code[lo_, hi_, x_] := N[(N[(x - lo), $MachinePrecision] / N[(hi - lo), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{x - lo}{hi - lo}
\end{array}

Alternative 1: 19.4% accurate, 0.1× speedup?

\[\begin{array}{l} \\ \left(\frac{\frac{-1}{lo}}{\frac{-1}{hi - x}} \cdot {lo}^{-1}\right) \cdot hi \end{array} \]
(FPCore (lo hi x)
 :precision binary64
 (* (* (/ (/ -1.0 lo) (/ -1.0 (- hi x))) (pow lo -1.0)) hi))
double code(double lo, double hi, double x) {
	return (((-1.0 / lo) / (-1.0 / (hi - x))) * pow(lo, -1.0)) * hi;
}
real(8) function code(lo, hi, x)
    real(8), intent (in) :: lo
    real(8), intent (in) :: hi
    real(8), intent (in) :: x
    code = ((((-1.0d0) / lo) / ((-1.0d0) / (hi - x))) * (lo ** (-1.0d0))) * hi
end function
public static double code(double lo, double hi, double x) {
	return (((-1.0 / lo) / (-1.0 / (hi - x))) * Math.pow(lo, -1.0)) * hi;
}
def code(lo, hi, x):
	return (((-1.0 / lo) / (-1.0 / (hi - x))) * math.pow(lo, -1.0)) * hi
function code(lo, hi, x)
	return Float64(Float64(Float64(Float64(-1.0 / lo) / Float64(-1.0 / Float64(hi - x))) * (lo ^ -1.0)) * hi)
end
function tmp = code(lo, hi, x)
	tmp = (((-1.0 / lo) / (-1.0 / (hi - x))) * (lo ^ -1.0)) * hi;
end
code[lo_, hi_, x_] := N[(N[(N[(N[(-1.0 / lo), $MachinePrecision] / N[(-1.0 / N[(hi - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Power[lo, -1.0], $MachinePrecision]), $MachinePrecision] * hi), $MachinePrecision]
\begin{array}{l}

\\
\left(\frac{\frac{-1}{lo}}{\frac{-1}{hi - x}} \cdot {lo}^{-1}\right) \cdot hi
\end{array}
Derivation
  1. Initial program 3.1%

    \[\frac{x - lo}{hi - lo} \]
  2. Add Preprocessing
  3. Taylor expanded in lo around -inf

    \[\leadsto \color{blue}{1 + -1 \cdot \frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
  4. Step-by-step derivation
    1. mul-1-negN/A

      \[\leadsto 1 + \color{blue}{\left(\mathsf{neg}\left(\frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}\right)\right)} \]
    2. unsub-negN/A

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

      \[\leadsto \color{blue}{1 - \frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
    4. lower-/.f64N/A

      \[\leadsto 1 - \color{blue}{\frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
    5. +-commutativeN/A

      \[\leadsto 1 - \frac{\color{blue}{\left(\frac{hi \cdot \left(x - hi\right)}{lo} + x\right)} - hi}{lo} \]
    6. associate--l+N/A

      \[\leadsto 1 - \frac{\color{blue}{\frac{hi \cdot \left(x - hi\right)}{lo} + \left(x - hi\right)}}{lo} \]
    7. associate-/l*N/A

      \[\leadsto 1 - \frac{\color{blue}{hi \cdot \frac{x - hi}{lo}} + \left(x - hi\right)}{lo} \]
    8. *-commutativeN/A

      \[\leadsto 1 - \frac{\color{blue}{\frac{x - hi}{lo} \cdot hi} + \left(x - hi\right)}{lo} \]
    9. lower-fma.f64N/A

      \[\leadsto 1 - \frac{\color{blue}{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, x - hi\right)}}{lo} \]
    10. lower-/.f64N/A

      \[\leadsto 1 - \frac{\mathsf{fma}\left(\color{blue}{\frac{x - hi}{lo}}, hi, x - hi\right)}{lo} \]
    11. lower--.f64N/A

      \[\leadsto 1 - \frac{\mathsf{fma}\left(\frac{\color{blue}{x - hi}}{lo}, hi, x - hi\right)}{lo} \]
    12. lower--.f6418.8

      \[\leadsto 1 - \frac{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, \color{blue}{x - hi}\right)}{lo} \]
  5. Applied rewrites18.8%

    \[\leadsto \color{blue}{1 - \frac{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, x - hi\right)}{lo}} \]
  6. Taylor expanded in lo around 0

    \[\leadsto -1 \cdot \color{blue}{\frac{hi \cdot \left(x - hi\right)}{{lo}^{2}}} \]
  7. Step-by-step derivation
    1. Applied rewrites19.5%

      \[\leadsto \frac{\frac{hi - x}{lo}}{lo} \cdot \color{blue}{hi} \]
    2. Step-by-step derivation
      1. Applied rewrites19.5%

        \[\leadsto \left({lo}^{-1} \cdot \frac{{lo}^{-1}}{{\left(hi - x\right)}^{-1}}\right) \cdot hi \]
      2. Step-by-step derivation
        1. Applied rewrites19.5%

          \[\leadsto \left({lo}^{-1} \cdot \frac{\frac{-1}{lo}}{\frac{-1}{hi - x}}\right) \cdot hi \]
        2. Final simplification19.5%

          \[\leadsto \left(\frac{\frac{-1}{lo}}{\frac{-1}{hi - x}} \cdot {lo}^{-1}\right) \cdot hi \]
        3. Add Preprocessing

        Alternative 2: 19.4% accurate, 0.6× speedup?

        \[\begin{array}{l} \\ \frac{\frac{hi}{lo}}{lo} \cdot \left(hi - x\right) \end{array} \]
        (FPCore (lo hi x) :precision binary64 (* (/ (/ hi lo) lo) (- hi x)))
        double code(double lo, double hi, double x) {
        	return ((hi / lo) / lo) * (hi - x);
        }
        
        real(8) function code(lo, hi, x)
            real(8), intent (in) :: lo
            real(8), intent (in) :: hi
            real(8), intent (in) :: x
            code = ((hi / lo) / lo) * (hi - x)
        end function
        
        public static double code(double lo, double hi, double x) {
        	return ((hi / lo) / lo) * (hi - x);
        }
        
        def code(lo, hi, x):
        	return ((hi / lo) / lo) * (hi - x)
        
        function code(lo, hi, x)
        	return Float64(Float64(Float64(hi / lo) / lo) * Float64(hi - x))
        end
        
        function tmp = code(lo, hi, x)
        	tmp = ((hi / lo) / lo) * (hi - x);
        end
        
        code[lo_, hi_, x_] := N[(N[(N[(hi / lo), $MachinePrecision] / lo), $MachinePrecision] * N[(hi - x), $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \frac{\frac{hi}{lo}}{lo} \cdot \left(hi - x\right)
        \end{array}
        
        Derivation
        1. Initial program 3.1%

          \[\frac{x - lo}{hi - lo} \]
        2. Add Preprocessing
        3. Taylor expanded in lo around -inf

          \[\leadsto \color{blue}{1 + -1 \cdot \frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
        4. Step-by-step derivation
          1. mul-1-negN/A

            \[\leadsto 1 + \color{blue}{\left(\mathsf{neg}\left(\frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}\right)\right)} \]
          2. unsub-negN/A

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

            \[\leadsto \color{blue}{1 - \frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
          4. lower-/.f64N/A

            \[\leadsto 1 - \color{blue}{\frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
          5. +-commutativeN/A

            \[\leadsto 1 - \frac{\color{blue}{\left(\frac{hi \cdot \left(x - hi\right)}{lo} + x\right)} - hi}{lo} \]
          6. associate--l+N/A

            \[\leadsto 1 - \frac{\color{blue}{\frac{hi \cdot \left(x - hi\right)}{lo} + \left(x - hi\right)}}{lo} \]
          7. associate-/l*N/A

            \[\leadsto 1 - \frac{\color{blue}{hi \cdot \frac{x - hi}{lo}} + \left(x - hi\right)}{lo} \]
          8. *-commutativeN/A

            \[\leadsto 1 - \frac{\color{blue}{\frac{x - hi}{lo} \cdot hi} + \left(x - hi\right)}{lo} \]
          9. lower-fma.f64N/A

            \[\leadsto 1 - \frac{\color{blue}{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, x - hi\right)}}{lo} \]
          10. lower-/.f64N/A

            \[\leadsto 1 - \frac{\mathsf{fma}\left(\color{blue}{\frac{x - hi}{lo}}, hi, x - hi\right)}{lo} \]
          11. lower--.f64N/A

            \[\leadsto 1 - \frac{\mathsf{fma}\left(\frac{\color{blue}{x - hi}}{lo}, hi, x - hi\right)}{lo} \]
          12. lower--.f6418.8

            \[\leadsto 1 - \frac{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, \color{blue}{x - hi}\right)}{lo} \]
        5. Applied rewrites18.8%

          \[\leadsto \color{blue}{1 - \frac{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, x - hi\right)}{lo}} \]
        6. Taylor expanded in lo around 0

          \[\leadsto -1 \cdot \color{blue}{\frac{hi \cdot \left(x - hi\right)}{{lo}^{2}}} \]
        7. Step-by-step derivation
          1. Applied rewrites19.5%

            \[\leadsto \frac{\frac{hi - x}{lo}}{lo} \cdot \color{blue}{hi} \]
          2. Taylor expanded in lo around 0

            \[\leadsto -1 \cdot \color{blue}{\frac{hi \cdot \left(x - hi\right)}{{lo}^{2}}} \]
          3. Step-by-step derivation
            1. Applied rewrites19.5%

              \[\leadsto \left(hi - x\right) \cdot \color{blue}{\frac{\frac{hi}{lo}}{lo}} \]
            2. Final simplification19.5%

              \[\leadsto \frac{\frac{hi}{lo}}{lo} \cdot \left(hi - x\right) \]
            3. Add Preprocessing

            Alternative 3: 19.4% accurate, 0.6× speedup?

            \[\begin{array}{l} \\ \frac{\frac{hi}{lo}}{lo} \cdot hi \end{array} \]
            (FPCore (lo hi x) :precision binary64 (* (/ (/ hi lo) lo) hi))
            double code(double lo, double hi, double x) {
            	return ((hi / lo) / lo) * hi;
            }
            
            real(8) function code(lo, hi, x)
                real(8), intent (in) :: lo
                real(8), intent (in) :: hi
                real(8), intent (in) :: x
                code = ((hi / lo) / lo) * hi
            end function
            
            public static double code(double lo, double hi, double x) {
            	return ((hi / lo) / lo) * hi;
            }
            
            def code(lo, hi, x):
            	return ((hi / lo) / lo) * hi
            
            function code(lo, hi, x)
            	return Float64(Float64(Float64(hi / lo) / lo) * hi)
            end
            
            function tmp = code(lo, hi, x)
            	tmp = ((hi / lo) / lo) * hi;
            end
            
            code[lo_, hi_, x_] := N[(N[(N[(hi / lo), $MachinePrecision] / lo), $MachinePrecision] * hi), $MachinePrecision]
            
            \begin{array}{l}
            
            \\
            \frac{\frac{hi}{lo}}{lo} \cdot hi
            \end{array}
            
            Derivation
            1. Initial program 3.1%

              \[\frac{x - lo}{hi - lo} \]
            2. Add Preprocessing
            3. Taylor expanded in lo around -inf

              \[\leadsto \color{blue}{1 + -1 \cdot \frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
            4. Step-by-step derivation
              1. mul-1-negN/A

                \[\leadsto 1 + \color{blue}{\left(\mathsf{neg}\left(\frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}\right)\right)} \]
              2. unsub-negN/A

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

                \[\leadsto \color{blue}{1 - \frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
              4. lower-/.f64N/A

                \[\leadsto 1 - \color{blue}{\frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
              5. +-commutativeN/A

                \[\leadsto 1 - \frac{\color{blue}{\left(\frac{hi \cdot \left(x - hi\right)}{lo} + x\right)} - hi}{lo} \]
              6. associate--l+N/A

                \[\leadsto 1 - \frac{\color{blue}{\frac{hi \cdot \left(x - hi\right)}{lo} + \left(x - hi\right)}}{lo} \]
              7. associate-/l*N/A

                \[\leadsto 1 - \frac{\color{blue}{hi \cdot \frac{x - hi}{lo}} + \left(x - hi\right)}{lo} \]
              8. *-commutativeN/A

                \[\leadsto 1 - \frac{\color{blue}{\frac{x - hi}{lo} \cdot hi} + \left(x - hi\right)}{lo} \]
              9. lower-fma.f64N/A

                \[\leadsto 1 - \frac{\color{blue}{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, x - hi\right)}}{lo} \]
              10. lower-/.f64N/A

                \[\leadsto 1 - \frac{\mathsf{fma}\left(\color{blue}{\frac{x - hi}{lo}}, hi, x - hi\right)}{lo} \]
              11. lower--.f64N/A

                \[\leadsto 1 - \frac{\mathsf{fma}\left(\frac{\color{blue}{x - hi}}{lo}, hi, x - hi\right)}{lo} \]
              12. lower--.f6418.8

                \[\leadsto 1 - \frac{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, \color{blue}{x - hi}\right)}{lo} \]
            5. Applied rewrites18.8%

              \[\leadsto \color{blue}{1 - \frac{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, x - hi\right)}{lo}} \]
            6. Taylor expanded in lo around 0

              \[\leadsto -1 \cdot \color{blue}{\frac{hi \cdot \left(x - hi\right)}{{lo}^{2}}} \]
            7. Step-by-step derivation
              1. Applied rewrites19.5%

                \[\leadsto \frac{\frac{hi - x}{lo}}{lo} \cdot \color{blue}{hi} \]
              2. Taylor expanded in hi around inf

                \[\leadsto \frac{{hi}^{2}}{\color{blue}{{lo}^{2}}} \]
              3. Step-by-step derivation
                1. Applied rewrites19.5%

                  \[\leadsto \frac{\frac{hi}{lo}}{lo} \cdot \color{blue}{hi} \]
                2. Add Preprocessing

                Alternative 4: 19.4% accurate, 0.6× speedup?

                \[\begin{array}{l} \\ \frac{hi}{lo} \cdot \frac{hi}{lo} \end{array} \]
                (FPCore (lo hi x) :precision binary64 (* (/ hi lo) (/ hi lo)))
                double code(double lo, double hi, double x) {
                	return (hi / lo) * (hi / lo);
                }
                
                real(8) function code(lo, hi, x)
                    real(8), intent (in) :: lo
                    real(8), intent (in) :: hi
                    real(8), intent (in) :: x
                    code = (hi / lo) * (hi / lo)
                end function
                
                public static double code(double lo, double hi, double x) {
                	return (hi / lo) * (hi / lo);
                }
                
                def code(lo, hi, x):
                	return (hi / lo) * (hi / lo)
                
                function code(lo, hi, x)
                	return Float64(Float64(hi / lo) * Float64(hi / lo))
                end
                
                function tmp = code(lo, hi, x)
                	tmp = (hi / lo) * (hi / lo);
                end
                
                code[lo_, hi_, x_] := N[(N[(hi / lo), $MachinePrecision] * N[(hi / lo), $MachinePrecision]), $MachinePrecision]
                
                \begin{array}{l}
                
                \\
                \frac{hi}{lo} \cdot \frac{hi}{lo}
                \end{array}
                
                Derivation
                1. Initial program 3.1%

                  \[\frac{x - lo}{hi - lo} \]
                2. Add Preprocessing
                3. Taylor expanded in lo around -inf

                  \[\leadsto \color{blue}{1 + -1 \cdot \frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
                4. Step-by-step derivation
                  1. mul-1-negN/A

                    \[\leadsto 1 + \color{blue}{\left(\mathsf{neg}\left(\frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}\right)\right)} \]
                  2. unsub-negN/A

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

                    \[\leadsto \color{blue}{1 - \frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
                  4. lower-/.f64N/A

                    \[\leadsto 1 - \color{blue}{\frac{\left(x + \frac{hi \cdot \left(x - hi\right)}{lo}\right) - hi}{lo}} \]
                  5. +-commutativeN/A

                    \[\leadsto 1 - \frac{\color{blue}{\left(\frac{hi \cdot \left(x - hi\right)}{lo} + x\right)} - hi}{lo} \]
                  6. associate--l+N/A

                    \[\leadsto 1 - \frac{\color{blue}{\frac{hi \cdot \left(x - hi\right)}{lo} + \left(x - hi\right)}}{lo} \]
                  7. associate-/l*N/A

                    \[\leadsto 1 - \frac{\color{blue}{hi \cdot \frac{x - hi}{lo}} + \left(x - hi\right)}{lo} \]
                  8. *-commutativeN/A

                    \[\leadsto 1 - \frac{\color{blue}{\frac{x - hi}{lo} \cdot hi} + \left(x - hi\right)}{lo} \]
                  9. lower-fma.f64N/A

                    \[\leadsto 1 - \frac{\color{blue}{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, x - hi\right)}}{lo} \]
                  10. lower-/.f64N/A

                    \[\leadsto 1 - \frac{\mathsf{fma}\left(\color{blue}{\frac{x - hi}{lo}}, hi, x - hi\right)}{lo} \]
                  11. lower--.f64N/A

                    \[\leadsto 1 - \frac{\mathsf{fma}\left(\frac{\color{blue}{x - hi}}{lo}, hi, x - hi\right)}{lo} \]
                  12. lower--.f6418.8

                    \[\leadsto 1 - \frac{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, \color{blue}{x - hi}\right)}{lo} \]
                5. Applied rewrites18.8%

                  \[\leadsto \color{blue}{1 - \frac{\mathsf{fma}\left(\frac{x - hi}{lo}, hi, x - hi\right)}{lo}} \]
                6. Taylor expanded in hi around inf

                  \[\leadsto \frac{{hi}^{2}}{\color{blue}{{lo}^{2}}} \]
                7. Step-by-step derivation
                  1. Applied rewrites19.5%

                    \[\leadsto \frac{hi}{lo} \cdot \color{blue}{\frac{hi}{lo}} \]
                  2. Add Preprocessing

                  Alternative 5: 18.8% accurate, 1.3× speedup?

                  \[\begin{array}{l} \\ \frac{-lo}{hi} \end{array} \]
                  (FPCore (lo hi x) :precision binary64 (/ (- lo) hi))
                  double code(double lo, double hi, double x) {
                  	return -lo / hi;
                  }
                  
                  real(8) function code(lo, hi, x)
                      real(8), intent (in) :: lo
                      real(8), intent (in) :: hi
                      real(8), intent (in) :: x
                      code = -lo / hi
                  end function
                  
                  public static double code(double lo, double hi, double x) {
                  	return -lo / hi;
                  }
                  
                  def code(lo, hi, x):
                  	return -lo / hi
                  
                  function code(lo, hi, x)
                  	return Float64(Float64(-lo) / hi)
                  end
                  
                  function tmp = code(lo, hi, x)
                  	tmp = -lo / hi;
                  end
                  
                  code[lo_, hi_, x_] := N[((-lo) / hi), $MachinePrecision]
                  
                  \begin{array}{l}
                  
                  \\
                  \frac{-lo}{hi}
                  \end{array}
                  
                  Derivation
                  1. Initial program 3.1%

                    \[\frac{x - lo}{hi - lo} \]
                  2. Add Preprocessing
                  3. Taylor expanded in hi around inf

                    \[\leadsto \color{blue}{\frac{x - lo}{hi}} \]
                  4. Step-by-step derivation
                    1. lower-/.f64N/A

                      \[\leadsto \color{blue}{\frac{x - lo}{hi}} \]
                    2. lower--.f6418.8

                      \[\leadsto \frac{\color{blue}{x - lo}}{hi} \]
                  5. Applied rewrites18.8%

                    \[\leadsto \color{blue}{\frac{x - lo}{hi}} \]
                  6. Taylor expanded in lo around inf

                    \[\leadsto \frac{-1 \cdot lo}{hi} \]
                  7. Step-by-step derivation
                    1. Applied rewrites18.8%

                      \[\leadsto \frac{-lo}{hi} \]
                    2. Add Preprocessing

                    Alternative 6: 18.7% accurate, 18.0× speedup?

                    \[\begin{array}{l} \\ 1 \end{array} \]
                    (FPCore (lo hi x) :precision binary64 1.0)
                    double code(double lo, double hi, double x) {
                    	return 1.0;
                    }
                    
                    real(8) function code(lo, hi, x)
                        real(8), intent (in) :: lo
                        real(8), intent (in) :: hi
                        real(8), intent (in) :: x
                        code = 1.0d0
                    end function
                    
                    public static double code(double lo, double hi, double x) {
                    	return 1.0;
                    }
                    
                    def code(lo, hi, x):
                    	return 1.0
                    
                    function code(lo, hi, x)
                    	return 1.0
                    end
                    
                    function tmp = code(lo, hi, x)
                    	tmp = 1.0;
                    end
                    
                    code[lo_, hi_, x_] := 1.0
                    
                    \begin{array}{l}
                    
                    \\
                    1
                    \end{array}
                    
                    Derivation
                    1. Initial program 3.1%

                      \[\frac{x - lo}{hi - lo} \]
                    2. Add Preprocessing
                    3. Taylor expanded in lo around inf

                      \[\leadsto \color{blue}{1} \]
                    4. Step-by-step derivation
                      1. Applied rewrites18.7%

                        \[\leadsto \color{blue}{1} \]
                      2. Add Preprocessing

                      Reproduce

                      ?
                      herbie shell --seed 2024268 
                      (FPCore (lo hi x)
                        :name "xlohi (overflows)"
                        :precision binary64
                        :pre (and (< lo -1e+308) (> hi 1e+308))
                        (/ (- x lo) (- hi lo)))