code[x_, y_, z_, t_, a_, b_, c_, i_] := N[(x * y + N[(z * t + N[(c * i + N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\left(\left(x \cdot y + z \cdot t\right) + a \cdot b\right) + c \cdot i
↓
\mathsf{fma}\left(x, y, \mathsf{fma}\left(z, t, \mathsf{fma}\left(c, i, a \cdot b\right)\right)\right)
Error
Derivation
Initial program 0.0
\[\left(\left(x \cdot y + z \cdot t\right) + a \cdot b\right) + c \cdot i
\]
Simplified0.0
\[\leadsto \color{blue}{\mathsf{fma}\left(x, y, \mathsf{fma}\left(z, t, \mathsf{fma}\left(c, i, a \cdot b\right)\right)\right)}
\]
Proof
(fma.f64 x y (fma.f64 z t (fma.f64 c i (*.f64 a b)))): 0 points increase in error, 0 points decrease in error
(fma.f64 x y (fma.f64 z t (Rewrite<= fma-def_binary64 (+.f64 (*.f64 c i) (*.f64 a b))))): 1 points increase in error, 0 points decrease in error
(fma.f64 x y (fma.f64 z t (Rewrite<= +-commutative_binary64 (+.f64 (*.f64 a b) (*.f64 c i))))): 0 points increase in error, 0 points decrease in error
(fma.f64 x y (Rewrite<= fma-def_binary64 (+.f64 (*.f64 z t) (+.f64 (*.f64 a b) (*.f64 c i))))): 2 points increase in error, 0 points decrease in error
(Rewrite<= fma-def_binary64 (+.f64 (*.f64 x y) (+.f64 (*.f64 z t) (+.f64 (*.f64 a b) (*.f64 c i))))): 1 points increase in error, 0 points decrease in error
(Rewrite<= associate-+l+_binary64 (+.f64 (+.f64 (*.f64 x y) (*.f64 z t)) (+.f64 (*.f64 a b) (*.f64 c i)))): 0 points increase in error, 0 points decrease in error
(Rewrite<= associate-+l+_binary64 (+.f64 (+.f64 (+.f64 (*.f64 x y) (*.f64 z t)) (*.f64 a b)) (*.f64 c i))): 0 points increase in error, 0 points decrease in error
Final simplification0.0
\[\leadsto \mathsf{fma}\left(x, y, \mathsf{fma}\left(z, t, \mathsf{fma}\left(c, i, a \cdot b\right)\right)\right)
\]
Alternatives
Alternative 1
Error
0.0
Cost
19776
\[\mathsf{fma}\left(c, i, \mathsf{fma}\left(a, b, \mathsf{fma}\left(x, y, z \cdot t\right)\right)\right)
\]
Alternative 2
Error
22.2
Cost
2268
\[\begin{array}{l}
t_1 := a \cdot b + x \cdot y\\
t_2 := c \cdot i + x \cdot y\\
t_3 := a \cdot b + z \cdot t\\
\mathbf{if}\;c \cdot i \leq -4 \cdot 10^{+26}:\\
\;\;\;\;c \cdot i + z \cdot t\\
\mathbf{elif}\;c \cdot i \leq -3.15 \cdot 10^{-261}:\\
\;\;\;\;t_1\\
\mathbf{elif}\;c \cdot i \leq 1.25 \cdot 10^{-303}:\\
\;\;\;\;t_3\\
\mathbf{elif}\;c \cdot i \leq 2.4 \cdot 10^{-209}:\\
\;\;\;\;t_1\\
\mathbf{elif}\;c \cdot i \leq 1.85 \cdot 10^{-51}:\\
\;\;\;\;t_3\\
\mathbf{elif}\;c \cdot i \leq 8.8 \cdot 10^{+71}:\\
\;\;\;\;t_2\\
\mathbf{elif}\;c \cdot i \leq 10^{+217}:\\
\;\;\;\;a \cdot b + c \cdot i\\
\mathbf{else}:\\
\;\;\;\;t_2\\
\end{array}
\]
Alternative 3
Error
22.1
Cost
2268
\[\begin{array}{l}
t_1 := z \cdot t + x \cdot y\\
t_2 := c \cdot i + x \cdot y\\
\mathbf{if}\;c \cdot i \leq -2.8 \cdot 10^{+58}:\\
\;\;\;\;c \cdot i + z \cdot t\\
\mathbf{elif}\;c \cdot i \leq 2.85 \cdot 10^{-304}:\\
\;\;\;\;t_1\\
\mathbf{elif}\;c \cdot i \leq 1.75 \cdot 10^{-251}:\\
\;\;\;\;a \cdot b + x \cdot y\\
\mathbf{elif}\;c \cdot i \leq 1.7 \cdot 10^{-172}:\\
\;\;\;\;t_1\\
\mathbf{elif}\;c \cdot i \leq 2.05 \cdot 10^{-51}:\\
\;\;\;\;a \cdot b + z \cdot t\\
\mathbf{elif}\;c \cdot i \leq 2 \cdot 10^{+77}:\\
\;\;\;\;t_2\\
\mathbf{elif}\;c \cdot i \leq 3 \cdot 10^{+219}:\\
\;\;\;\;a \cdot b + c \cdot i\\
\mathbf{else}:\\
\;\;\;\;t_2\\
\end{array}
\]
Alternative 4
Error
21.7
Cost
2008
\[\begin{array}{l}
t_1 := a \cdot b + x \cdot y\\
t_2 := a \cdot b + z \cdot t\\
\mathbf{if}\;c \cdot i \leq -3.8 \cdot 10^{+19}:\\
\;\;\;\;c \cdot i + z \cdot t\\
\mathbf{elif}\;c \cdot i \leq -1.02 \cdot 10^{-260}:\\
\;\;\;\;t_1\\
\mathbf{elif}\;c \cdot i \leq 4.9 \cdot 10^{-296}:\\
\;\;\;\;t_2\\
\mathbf{elif}\;c \cdot i \leq 2.3 \cdot 10^{-209}:\\
\;\;\;\;t_1\\
\mathbf{elif}\;c \cdot i \leq 2.05 \cdot 10^{-51}:\\
\;\;\;\;t_2\\
\mathbf{elif}\;c \cdot i \leq 3.2 \cdot 10^{+24}:\\
\;\;\;\;t_1\\
\mathbf{else}:\\
\;\;\;\;a \cdot b + c \cdot i\\
\end{array}
\]
\[\begin{array}{l}
\mathbf{if}\;c \cdot i \leq -1 \cdot 10^{+61}:\\
\;\;\;\;c \cdot i + z \cdot t\\
\mathbf{elif}\;c \cdot i \leq 4.8 \cdot 10^{+25}:\\
\;\;\;\;a \cdot b + \left(z \cdot t + x \cdot y\right)\\
\mathbf{elif}\;c \cdot i \leq 4 \cdot 10^{+218}:\\
\;\;\;\;a \cdot b + c \cdot i\\
\mathbf{else}:\\
\;\;\;\;c \cdot i + x \cdot y\\
\end{array}
\]
Alternative 11
Error
0.0
Cost
960
\[\left(a \cdot b + \left(z \cdot t + x \cdot y\right)\right) + c \cdot i
\]
herbie shell --seed 2022332
(FPCore (x y z t a b c i)
:name "Linear.V4:$cdot from linear-1.19.1.3, C"
:precision binary64
(+ (+ (+ (* x y) (* z t)) (* a b)) (* c i)))