Average Error: 62.0 → 43.7
Time: 7.5s
Precision: binary64
Cost: 8448
\[lo < -1 \cdot 10^{+308} \land hi > 10^{+308}\]
\[\frac{x - lo}{hi - lo} \]
\[\frac{1 + {\left(\frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo}\right)}^{3}}{\frac{hi}{lo} \cdot \frac{hi}{lo} + \left(1 + \frac{hi \cdot \left(-1 - \frac{hi}{lo}\right)}{lo}\right)} \]
(FPCore (lo hi x) :precision binary64 (/ (- x lo) (- hi lo)))
(FPCore (lo hi x)
 :precision binary64
 (/
  (+ 1.0 (pow (/ (* hi (+ (/ hi lo) 1.0)) lo) 3.0))
  (+ (* (/ hi lo) (/ hi lo)) (+ 1.0 (/ (* hi (- -1.0 (/ hi lo))) lo)))))
double code(double lo, double hi, double x) {
	return (x - lo) / (hi - lo);
}
double code(double lo, double hi, double x) {
	return (1.0 + pow(((hi * ((hi / lo) + 1.0)) / lo), 3.0)) / (((hi / lo) * (hi / lo)) + (1.0 + ((hi * (-1.0 - (hi / lo))) / 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
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 + (((hi * ((hi / lo) + 1.0d0)) / lo) ** 3.0d0)) / (((hi / lo) * (hi / lo)) + (1.0d0 + ((hi * ((-1.0d0) - (hi / lo))) / lo)))
end function
public static double code(double lo, double hi, double x) {
	return (x - lo) / (hi - lo);
}
public static double code(double lo, double hi, double x) {
	return (1.0 + Math.pow(((hi * ((hi / lo) + 1.0)) / lo), 3.0)) / (((hi / lo) * (hi / lo)) + (1.0 + ((hi * (-1.0 - (hi / lo))) / lo)));
}
def code(lo, hi, x):
	return (x - lo) / (hi - lo)
def code(lo, hi, x):
	return (1.0 + math.pow(((hi * ((hi / lo) + 1.0)) / lo), 3.0)) / (((hi / lo) * (hi / lo)) + (1.0 + ((hi * (-1.0 - (hi / lo))) / lo)))
function code(lo, hi, x)
	return Float64(Float64(x - lo) / Float64(hi - lo))
end
function code(lo, hi, x)
	return Float64(Float64(1.0 + (Float64(Float64(hi * Float64(Float64(hi / lo) + 1.0)) / lo) ^ 3.0)) / Float64(Float64(Float64(hi / lo) * Float64(hi / lo)) + Float64(1.0 + Float64(Float64(hi * Float64(-1.0 - Float64(hi / lo))) / lo))))
end
function tmp = code(lo, hi, x)
	tmp = (x - lo) / (hi - lo);
end
function tmp = code(lo, hi, x)
	tmp = (1.0 + (((hi * ((hi / lo) + 1.0)) / lo) ^ 3.0)) / (((hi / lo) * (hi / lo)) + (1.0 + ((hi * (-1.0 - (hi / lo))) / lo)));
end
code[lo_, hi_, x_] := N[(N[(x - lo), $MachinePrecision] / N[(hi - lo), $MachinePrecision]), $MachinePrecision]
code[lo_, hi_, x_] := N[(N[(1.0 + N[Power[N[(N[(hi * N[(N[(hi / lo), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision] / lo), $MachinePrecision], 3.0], $MachinePrecision]), $MachinePrecision] / N[(N[(N[(hi / lo), $MachinePrecision] * N[(hi / lo), $MachinePrecision]), $MachinePrecision] + N[(1.0 + N[(N[(hi * N[(-1.0 - N[(hi / lo), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / lo), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\frac{x - lo}{hi - lo}
\frac{1 + {\left(\frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo}\right)}^{3}}{\frac{hi}{lo} \cdot \frac{hi}{lo} + \left(1 + \frac{hi \cdot \left(-1 - \frac{hi}{lo}\right)}{lo}\right)}

Error

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Initial program 62.0

    \[\frac{x - lo}{hi - lo} \]
  2. Taylor expanded in lo around inf 64.0

    \[\leadsto \color{blue}{\left(-1 \cdot \frac{x}{lo} + \left(\frac{hi \cdot \left(-1 \cdot x - -1 \cdot hi\right)}{{lo}^{2}} + 1\right)\right) - -1 \cdot \frac{hi}{lo}} \]
  3. Simplified51.9

    \[\leadsto \color{blue}{1 + \frac{x - hi}{lo} \cdot \left(-1 - \frac{hi}{lo}\right)} \]
    Proof
    (+.f64 1 (*.f64 (/.f64 (-.f64 x hi) lo) (-.f64 -1 (/.f64 hi lo)))): 0 points increase in error, 0 points decrease in error
    (+.f64 1 (Rewrite<= distribute-rgt-out--_binary64 (-.f64 (*.f64 -1 (/.f64 (-.f64 x hi) lo)) (*.f64 (/.f64 hi lo) (/.f64 (-.f64 x hi) lo))))): 17 points increase in error, 10 points decrease in error
    (+.f64 1 (-.f64 (*.f64 -1 (/.f64 (-.f64 x hi) lo)) (Rewrite<= times-frac_binary64 (/.f64 (*.f64 hi (-.f64 x hi)) (*.f64 lo lo))))): 255 points increase in error, 0 points decrease in error
    (+.f64 1 (-.f64 (*.f64 -1 (/.f64 (-.f64 x hi) lo)) (/.f64 (Rewrite<= *-commutative_binary64 (*.f64 (-.f64 x hi) hi)) (*.f64 lo lo)))): 0 points increase in error, 0 points decrease in error
    (+.f64 1 (-.f64 (*.f64 -1 (/.f64 (-.f64 x hi) lo)) (/.f64 (*.f64 (-.f64 x hi) hi) (Rewrite<= unpow2_binary64 (pow.f64 lo 2))))): 0 points increase in error, 0 points decrease in error
    (+.f64 1 (Rewrite<= unsub-neg_binary64 (+.f64 (*.f64 -1 (/.f64 (-.f64 x hi) lo)) (neg.f64 (/.f64 (*.f64 (-.f64 x hi) hi) (pow.f64 lo 2)))))): 0 points increase in error, 0 points decrease in error
    (+.f64 1 (+.f64 (*.f64 -1 (/.f64 (-.f64 x hi) lo)) (Rewrite<= mul-1-neg_binary64 (*.f64 -1 (/.f64 (*.f64 (-.f64 x hi) hi) (pow.f64 lo 2)))))): 0 points increase in error, 0 points decrease in error
    (+.f64 1 (Rewrite=> +-commutative_binary64 (+.f64 (*.f64 -1 (/.f64 (*.f64 (-.f64 x hi) hi) (pow.f64 lo 2))) (*.f64 -1 (/.f64 (-.f64 x hi) lo))))): 0 points increase in error, 0 points decrease in error
    (Rewrite<= associate-+l+_binary64 (+.f64 (+.f64 1 (*.f64 -1 (/.f64 (*.f64 (-.f64 x hi) hi) (pow.f64 lo 2)))) (*.f64 -1 (/.f64 (-.f64 x hi) lo)))): 0 points increase in error, 0 points decrease in error
    (+.f64 (+.f64 1 (Rewrite=> associate-*r/_binary64 (/.f64 (*.f64 -1 (*.f64 (-.f64 x hi) hi)) (pow.f64 lo 2)))) (*.f64 -1 (/.f64 (-.f64 x hi) lo))): 0 points increase in error, 0 points decrease in error
    (+.f64 (+.f64 1 (/.f64 (Rewrite<= associate-*l*_binary64 (*.f64 (*.f64 -1 (-.f64 x hi)) hi)) (pow.f64 lo 2))) (*.f64 -1 (/.f64 (-.f64 x hi) lo))): 0 points increase in error, 0 points decrease in error
    (+.f64 (+.f64 1 (/.f64 (*.f64 (Rewrite<= distribute-lft-out--_binary64 (-.f64 (*.f64 -1 x) (*.f64 -1 hi))) hi) (pow.f64 lo 2))) (*.f64 -1 (/.f64 (-.f64 x hi) lo))): 0 points increase in error, 0 points decrease in error
    (+.f64 (+.f64 1 (/.f64 (Rewrite<= *-commutative_binary64 (*.f64 hi (-.f64 (*.f64 -1 x) (*.f64 -1 hi)))) (pow.f64 lo 2))) (*.f64 -1 (/.f64 (-.f64 x hi) lo))): 0 points increase in error, 0 points decrease in error
    (+.f64 (Rewrite<= +-commutative_binary64 (+.f64 (/.f64 (*.f64 hi (-.f64 (*.f64 -1 x) (*.f64 -1 hi))) (pow.f64 lo 2)) 1)) (*.f64 -1 (/.f64 (-.f64 x hi) lo))): 0 points increase in error, 0 points decrease in error
    (+.f64 (+.f64 (/.f64 (*.f64 hi (-.f64 (*.f64 -1 x) (*.f64 -1 hi))) (pow.f64 lo 2)) 1) (*.f64 -1 (Rewrite=> div-sub_binary64 (-.f64 (/.f64 x lo) (/.f64 hi lo))))): 0 points increase in error, 0 points decrease in error
    (+.f64 (+.f64 (/.f64 (*.f64 hi (-.f64 (*.f64 -1 x) (*.f64 -1 hi))) (pow.f64 lo 2)) 1) (Rewrite<= distribute-lft-out--_binary64 (-.f64 (*.f64 -1 (/.f64 x lo)) (*.f64 -1 (/.f64 hi lo))))): 0 points increase in error, 0 points decrease in error
    (Rewrite<= associate--l+_binary64 (-.f64 (+.f64 (+.f64 (/.f64 (*.f64 hi (-.f64 (*.f64 -1 x) (*.f64 -1 hi))) (pow.f64 lo 2)) 1) (*.f64 -1 (/.f64 x lo))) (*.f64 -1 (/.f64 hi lo)))): 0 points increase in error, 0 points decrease in error
    (-.f64 (Rewrite<= +-commutative_binary64 (+.f64 (*.f64 -1 (/.f64 x lo)) (+.f64 (/.f64 (*.f64 hi (-.f64 (*.f64 -1 x) (*.f64 -1 hi))) (pow.f64 lo 2)) 1))) (*.f64 -1 (/.f64 hi lo))): 0 points increase in error, 0 points decrease in error
  4. Taylor expanded in x around 0 51.9

    \[\leadsto \color{blue}{1 + \frac{\left(\frac{hi}{lo} + 1\right) \cdot hi}{lo}} \]
  5. Simplified51.9

    \[\leadsto \color{blue}{\mathsf{fma}\left(hi, \frac{\frac{hi}{lo} + 1}{lo}, 1\right)} \]
    Proof
    (fma.f64 hi (/.f64 (+.f64 (/.f64 hi lo) 1) lo) 1): 0 points increase in error, 0 points decrease in error
    (fma.f64 hi (/.f64 (Rewrite=> +-commutative_binary64 (+.f64 1 (/.f64 hi lo))) lo) 1): 0 points increase in error, 0 points decrease in error
    (Rewrite<= fma-def_binary64 (+.f64 (*.f64 hi (/.f64 (+.f64 1 (/.f64 hi lo)) lo)) 1)): 10 points increase in error, 10 points decrease in error
    (+.f64 (Rewrite=> associate-*r/_binary64 (/.f64 (*.f64 hi (+.f64 1 (/.f64 hi lo))) lo)) 1): 92 points increase in error, 99 points decrease in error
    (+.f64 (/.f64 (*.f64 hi (Rewrite<= +-commutative_binary64 (+.f64 (/.f64 hi lo) 1))) lo) 1): 0 points increase in error, 0 points decrease in error
    (+.f64 (/.f64 (Rewrite<= *-commutative_binary64 (*.f64 (+.f64 (/.f64 hi lo) 1) hi)) lo) 1): 0 points increase in error, 0 points decrease in error
    (Rewrite<= +-commutative_binary64 (+.f64 1 (/.f64 (*.f64 (+.f64 (/.f64 hi lo) 1) hi) lo))): 0 points increase in error, 0 points decrease in error
  6. Applied egg-rr51.9

    \[\leadsto \color{blue}{\frac{{\left(\frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo}\right)}^{3} + 1}{\frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo} \cdot \frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo} + \left(1 - \frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo} \cdot 1\right)}} \]
  7. Taylor expanded in hi around 0 64.0

    \[\leadsto \frac{{\left(\frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo}\right)}^{3} + 1}{\color{blue}{\frac{{hi}^{2}}{{lo}^{2}}} + \left(1 - \frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo} \cdot 1\right)} \]
  8. Simplified43.7

    \[\leadsto \frac{{\left(\frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo}\right)}^{3} + 1}{\color{blue}{\frac{hi}{lo} \cdot \frac{hi}{lo}} + \left(1 - \frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo} \cdot 1\right)} \]
    Proof
    (*.f64 (/.f64 hi lo) (/.f64 hi lo)): 0 points increase in error, 0 points decrease in error
    (Rewrite<= times-frac_binary64 (/.f64 (*.f64 hi hi) (*.f64 lo lo))): 256 points increase in error, 0 points decrease in error
    (/.f64 (Rewrite<= unpow2_binary64 (pow.f64 hi 2)) (*.f64 lo lo)): 0 points increase in error, 0 points decrease in error
    (/.f64 (pow.f64 hi 2) (Rewrite<= unpow2_binary64 (pow.f64 lo 2))): 0 points increase in error, 0 points decrease in error
  9. Final simplification43.7

    \[\leadsto \frac{1 + {\left(\frac{hi \cdot \left(\frac{hi}{lo} + 1\right)}{lo}\right)}^{3}}{\frac{hi}{lo} \cdot \frac{hi}{lo} + \left(1 + \frac{hi \cdot \left(-1 - \frac{hi}{lo}\right)}{lo}\right)} \]

Alternatives

Alternative 1
Error50.7
Cost7168
\[{\left(\left(-0.375 \cdot \frac{lo}{hi} - \frac{hi}{lo}\right) + -0.5\right)}^{2} \]
Alternative 2
Error51.6
Cost448
\[\frac{hi}{lo} \cdot \frac{hi}{lo} \]
Alternative 3
Error51.6
Cost448
\[hi \cdot \frac{\frac{hi}{lo}}{lo} \]
Alternative 4
Error52.0
Cost320
\[\frac{x - lo}{hi} \]
Alternative 5
Error52.0
Cost256
\[\frac{-lo}{hi} \]
Alternative 6
Error52.0
Cost64
\[1 \]

Error

Reproduce

herbie shell --seed 2022291 
(FPCore (lo hi x)
  :name "(/ (- x lo) (- hi lo))"
  :precision binary64
  :pre (and (< lo -1e+308) (> hi 1e+308))
  (/ (- x lo) (- hi lo)))