
(FPCore (x y z) :precision binary64 (* x (- 1.0 (* (- 1.0 y) z))))
double code(double x, double y, double z) {
return x * (1.0 - ((1.0 - y) * z));
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = x * (1.0d0 - ((1.0d0 - y) * z))
end function
public static double code(double x, double y, double z) {
return x * (1.0 - ((1.0 - y) * z));
}
def code(x, y, z): return x * (1.0 - ((1.0 - y) * z))
function code(x, y, z) return Float64(x * Float64(1.0 - Float64(Float64(1.0 - y) * z))) end
function tmp = code(x, y, z) tmp = x * (1.0 - ((1.0 - y) * z)); end
code[x_, y_, z_] := N[(x * N[(1.0 - N[(N[(1.0 - y), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x \cdot \left(1 - \left(1 - y\right) \cdot z\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 10 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z) :precision binary64 (* x (- 1.0 (* (- 1.0 y) z))))
double code(double x, double y, double z) {
return x * (1.0 - ((1.0 - y) * z));
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = x * (1.0d0 - ((1.0d0 - y) * z))
end function
public static double code(double x, double y, double z) {
return x * (1.0 - ((1.0 - y) * z));
}
def code(x, y, z): return x * (1.0 - ((1.0 - y) * z))
function code(x, y, z) return Float64(x * Float64(1.0 - Float64(Float64(1.0 - y) * z))) end
function tmp = code(x, y, z) tmp = x * (1.0 - ((1.0 - y) * z)); end
code[x_, y_, z_] := N[(x * N[(1.0 - N[(N[(1.0 - y), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x \cdot \left(1 - \left(1 - y\right) \cdot z\right)
\end{array}
(FPCore (x y z)
:precision binary64
(let* ((t_0 (* (- 1.0 y) z)) (t_1 (* (* x z) y)))
(if (<= t_0 (- INFINITY))
t_1
(if (<= t_0 1e+303) (fma (* z (- y 1.0)) x x) t_1))))
double code(double x, double y, double z) {
double t_0 = (1.0 - y) * z;
double t_1 = (x * z) * y;
double tmp;
if (t_0 <= -((double) INFINITY)) {
tmp = t_1;
} else if (t_0 <= 1e+303) {
tmp = fma((z * (y - 1.0)), x, x);
} else {
tmp = t_1;
}
return tmp;
}
function code(x, y, z) t_0 = Float64(Float64(1.0 - y) * z) t_1 = Float64(Float64(x * z) * y) tmp = 0.0 if (t_0 <= Float64(-Inf)) tmp = t_1; elseif (t_0 <= 1e+303) tmp = fma(Float64(z * Float64(y - 1.0)), x, x); else tmp = t_1; end return tmp end
code[x_, y_, z_] := Block[{t$95$0 = N[(N[(1.0 - y), $MachinePrecision] * z), $MachinePrecision]}, Block[{t$95$1 = N[(N[(x * z), $MachinePrecision] * y), $MachinePrecision]}, If[LessEqual[t$95$0, (-Infinity)], t$95$1, If[LessEqual[t$95$0, 1e+303], N[(N[(z * N[(y - 1.0), $MachinePrecision]), $MachinePrecision] * x + x), $MachinePrecision], t$95$1]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(1 - y\right) \cdot z\\
t_1 := \left(x \cdot z\right) \cdot y\\
\mathbf{if}\;t\_0 \leq -\infty:\\
\;\;\;\;t\_1\\
\mathbf{elif}\;t\_0 \leq 10^{+303}:\\
\;\;\;\;\mathsf{fma}\left(z \cdot \left(y - 1\right), x, x\right)\\
\mathbf{else}:\\
\;\;\;\;t\_1\\
\end{array}
\end{array}
if (*.f64 (-.f64 #s(literal 1 binary64) y) z) < -inf.0 or 1e303 < (*.f64 (-.f64 #s(literal 1 binary64) y) z) Initial program 66.6%
Taylor expanded in y around inf
*-commutativeN/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f64100.0
Applied rewrites100.0%
if -inf.0 < (*.f64 (-.f64 #s(literal 1 binary64) y) z) < 1e303Initial program 99.9%
Applied rewrites99.9%
Final simplification99.9%
(FPCore (x y z)
:precision binary64
(let* ((t_0 (fma (* z y) x x)))
(if (<= (- 1.0 y) -200.0)
t_0
(if (<= (- 1.0 y) 1.000001) (fma (- z) x x) t_0))))
double code(double x, double y, double z) {
double t_0 = fma((z * y), x, x);
double tmp;
if ((1.0 - y) <= -200.0) {
tmp = t_0;
} else if ((1.0 - y) <= 1.000001) {
tmp = fma(-z, x, x);
} else {
tmp = t_0;
}
return tmp;
}
function code(x, y, z) t_0 = fma(Float64(z * y), x, x) tmp = 0.0 if (Float64(1.0 - y) <= -200.0) tmp = t_0; elseif (Float64(1.0 - y) <= 1.000001) tmp = fma(Float64(-z), x, x); else tmp = t_0; end return tmp end
code[x_, y_, z_] := Block[{t$95$0 = N[(N[(z * y), $MachinePrecision] * x + x), $MachinePrecision]}, If[LessEqual[N[(1.0 - y), $MachinePrecision], -200.0], t$95$0, If[LessEqual[N[(1.0 - y), $MachinePrecision], 1.000001], N[((-z) * x + x), $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(z \cdot y, x, x\right)\\
\mathbf{if}\;1 - y \leq -200:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;1 - y \leq 1.000001:\\
\;\;\;\;\mathsf{fma}\left(-z, x, x\right)\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if (-.f64 #s(literal 1 binary64) y) < -200 or 1.00000099999999992 < (-.f64 #s(literal 1 binary64) y) Initial program 91.8%
Applied rewrites91.8%
Taylor expanded in y around inf
*-commutativeN/A
lower-*.f6490.7
Applied rewrites90.7%
if -200 < (-.f64 #s(literal 1 binary64) y) < 1.00000099999999992Initial program 100.0%
Applied rewrites100.0%
Taylor expanded in y around 0
mul-1-negN/A
lower-neg.f6499.5
Applied rewrites99.5%
(FPCore (x y z) :precision binary64 (let* ((t_0 (* (* x (- y 1.0)) z))) (if (<= z -1.2e-7) t_0 (if (<= z 0.14) (fma (* z y) x x) t_0))))
double code(double x, double y, double z) {
double t_0 = (x * (y - 1.0)) * z;
double tmp;
if (z <= -1.2e-7) {
tmp = t_0;
} else if (z <= 0.14) {
tmp = fma((z * y), x, x);
} else {
tmp = t_0;
}
return tmp;
}
function code(x, y, z) t_0 = Float64(Float64(x * Float64(y - 1.0)) * z) tmp = 0.0 if (z <= -1.2e-7) tmp = t_0; elseif (z <= 0.14) tmp = fma(Float64(z * y), x, x); else tmp = t_0; end return tmp end
code[x_, y_, z_] := Block[{t$95$0 = N[(N[(x * N[(y - 1.0), $MachinePrecision]), $MachinePrecision] * z), $MachinePrecision]}, If[LessEqual[z, -1.2e-7], t$95$0, If[LessEqual[z, 0.14], N[(N[(z * y), $MachinePrecision] * x + x), $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(x \cdot \left(y - 1\right)\right) \cdot z\\
\mathbf{if}\;z \leq -1.2 \cdot 10^{-7}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;z \leq 0.14:\\
\;\;\;\;\mathsf{fma}\left(z \cdot y, x, x\right)\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if z < -1.19999999999999989e-7 or 0.14000000000000001 < z Initial program 90.0%
Taylor expanded in z around inf
associate-*r*N/A
sub-negN/A
metadata-evalN/A
+-commutativeN/A
distribute-lft-inN/A
*-commutativeN/A
cancel-sign-subN/A
mul-1-negN/A
*-rgt-identityN/A
distribute-lft-out--N/A
mul-1-negN/A
distribute-lft-neg-inN/A
*-commutativeN/A
associate-*r*N/A
distribute-rgt-neg-inN/A
*-commutativeN/A
lower-*.f64N/A
Applied rewrites98.9%
if -1.19999999999999989e-7 < z < 0.14000000000000001Initial program 99.9%
Applied rewrites99.9%
Taylor expanded in y around inf
*-commutativeN/A
lower-*.f6499.5
Applied rewrites99.5%
Final simplification99.2%
(FPCore (x y z) :precision binary64 (if (<= y -7e+89) (* (* x z) y) (if (<= y 1.25e+46) (fma (- z) x x) (* (* x y) z))))
double code(double x, double y, double z) {
double tmp;
if (y <= -7e+89) {
tmp = (x * z) * y;
} else if (y <= 1.25e+46) {
tmp = fma(-z, x, x);
} else {
tmp = (x * y) * z;
}
return tmp;
}
function code(x, y, z) tmp = 0.0 if (y <= -7e+89) tmp = Float64(Float64(x * z) * y); elseif (y <= 1.25e+46) tmp = fma(Float64(-z), x, x); else tmp = Float64(Float64(x * y) * z); end return tmp end
code[x_, y_, z_] := If[LessEqual[y, -7e+89], N[(N[(x * z), $MachinePrecision] * y), $MachinePrecision], If[LessEqual[y, 1.25e+46], N[((-z) * x + x), $MachinePrecision], N[(N[(x * y), $MachinePrecision] * z), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq -7 \cdot 10^{+89}:\\
\;\;\;\;\left(x \cdot z\right) \cdot y\\
\mathbf{elif}\;y \leq 1.25 \cdot 10^{+46}:\\
\;\;\;\;\mathsf{fma}\left(-z, x, x\right)\\
\mathbf{else}:\\
\;\;\;\;\left(x \cdot y\right) \cdot z\\
\end{array}
\end{array}
if y < -7.0000000000000001e89Initial program 91.3%
Taylor expanded in y around inf
*-commutativeN/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f6476.6
Applied rewrites76.6%
if -7.0000000000000001e89 < y < 1.2500000000000001e46Initial program 99.3%
Applied rewrites99.3%
Taylor expanded in y around 0
mul-1-negN/A
lower-neg.f6494.5
Applied rewrites94.5%
if 1.2500000000000001e46 < y Initial program 90.0%
Taylor expanded in y around inf
*-commutativeN/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f6472.8
Applied rewrites72.8%
Applied rewrites73.0%
Final simplification85.8%
(FPCore (x y z) :precision binary64 (let* ((t_0 (* (* x z) y))) (if (<= y -7e+89) t_0 (if (<= y 1.25e+46) (fma (- z) x x) t_0))))
double code(double x, double y, double z) {
double t_0 = (x * z) * y;
double tmp;
if (y <= -7e+89) {
tmp = t_0;
} else if (y <= 1.25e+46) {
tmp = fma(-z, x, x);
} else {
tmp = t_0;
}
return tmp;
}
function code(x, y, z) t_0 = Float64(Float64(x * z) * y) tmp = 0.0 if (y <= -7e+89) tmp = t_0; elseif (y <= 1.25e+46) tmp = fma(Float64(-z), x, x); else tmp = t_0; end return tmp end
code[x_, y_, z_] := Block[{t$95$0 = N[(N[(x * z), $MachinePrecision] * y), $MachinePrecision]}, If[LessEqual[y, -7e+89], t$95$0, If[LessEqual[y, 1.25e+46], N[((-z) * x + x), $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(x \cdot z\right) \cdot y\\
\mathbf{if}\;y \leq -7 \cdot 10^{+89}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;y \leq 1.25 \cdot 10^{+46}:\\
\;\;\;\;\mathsf{fma}\left(-z, x, x\right)\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if y < -7.0000000000000001e89 or 1.2500000000000001e46 < y Initial program 90.5%
Taylor expanded in y around inf
*-commutativeN/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f6474.3
Applied rewrites74.3%
if -7.0000000000000001e89 < y < 1.2500000000000001e46Initial program 99.3%
Applied rewrites99.3%
Taylor expanded in y around 0
mul-1-negN/A
lower-neg.f6494.5
Applied rewrites94.5%
(FPCore (x y z) :precision binary64 (let* ((t_0 (* (- z) x))) (if (<= z -1.0) t_0 (if (<= z 7.2) (* 1.0 x) t_0))))
double code(double x, double y, double z) {
double t_0 = -z * x;
double tmp;
if (z <= -1.0) {
tmp = t_0;
} else if (z <= 7.2) {
tmp = 1.0 * x;
} else {
tmp = t_0;
}
return tmp;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: t_0
real(8) :: tmp
t_0 = -z * x
if (z <= (-1.0d0)) then
tmp = t_0
else if (z <= 7.2d0) then
tmp = 1.0d0 * x
else
tmp = t_0
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double t_0 = -z * x;
double tmp;
if (z <= -1.0) {
tmp = t_0;
} else if (z <= 7.2) {
tmp = 1.0 * x;
} else {
tmp = t_0;
}
return tmp;
}
def code(x, y, z): t_0 = -z * x tmp = 0 if z <= -1.0: tmp = t_0 elif z <= 7.2: tmp = 1.0 * x else: tmp = t_0 return tmp
function code(x, y, z) t_0 = Float64(Float64(-z) * x) tmp = 0.0 if (z <= -1.0) tmp = t_0; elseif (z <= 7.2) tmp = Float64(1.0 * x); else tmp = t_0; end return tmp end
function tmp_2 = code(x, y, z) t_0 = -z * x; tmp = 0.0; if (z <= -1.0) tmp = t_0; elseif (z <= 7.2) tmp = 1.0 * x; else tmp = t_0; end tmp_2 = tmp; end
code[x_, y_, z_] := Block[{t$95$0 = N[((-z) * x), $MachinePrecision]}, If[LessEqual[z, -1.0], t$95$0, If[LessEqual[z, 7.2], N[(1.0 * x), $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(-z\right) \cdot x\\
\mathbf{if}\;z \leq -1:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;z \leq 7.2:\\
\;\;\;\;1 \cdot x\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if z < -1 or 7.20000000000000018 < z Initial program 89.5%
Taylor expanded in y around 0
lower--.f6462.0
Applied rewrites62.0%
Taylor expanded in z around inf
Applied rewrites61.2%
if -1 < z < 7.20000000000000018Initial program 99.9%
Taylor expanded in y around 0
lower--.f6467.3
Applied rewrites67.3%
Taylor expanded in z around 0
Applied rewrites67.0%
Final simplification64.5%
(FPCore (x y z) :precision binary64 (fma (- y 1.0) (* x z) x))
double code(double x, double y, double z) {
return fma((y - 1.0), (x * z), x);
}
function code(x, y, z) return fma(Float64(y - 1.0), Float64(x * z), x) end
code[x_, y_, z_] := N[(N[(y - 1.0), $MachinePrecision] * N[(x * z), $MachinePrecision] + x), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(y - 1, x \cdot z, x\right)
\end{array}
Initial program 95.5%
Applied rewrites98.0%
Final simplification98.0%
(FPCore (x y z) :precision binary64 (fma (- z) x x))
double code(double x, double y, double z) {
return fma(-z, x, x);
}
function code(x, y, z) return fma(Float64(-z), x, x) end
code[x_, y_, z_] := N[((-z) * x + x), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-z, x, x\right)
\end{array}
Initial program 95.5%
Applied rewrites95.5%
Taylor expanded in y around 0
mul-1-negN/A
lower-neg.f6465.0
Applied rewrites65.0%
(FPCore (x y z) :precision binary64 (* (- 1.0 z) x))
double code(double x, double y, double z) {
return (1.0 - z) * x;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = (1.0d0 - z) * x
end function
public static double code(double x, double y, double z) {
return (1.0 - z) * x;
}
def code(x, y, z): return (1.0 - z) * x
function code(x, y, z) return Float64(Float64(1.0 - z) * x) end
function tmp = code(x, y, z) tmp = (1.0 - z) * x; end
code[x_, y_, z_] := N[(N[(1.0 - z), $MachinePrecision] * x), $MachinePrecision]
\begin{array}{l}
\\
\left(1 - z\right) \cdot x
\end{array}
Initial program 95.5%
Taylor expanded in y around 0
lower--.f6465.0
Applied rewrites65.0%
Final simplification65.0%
(FPCore (x y z) :precision binary64 (* 1.0 x))
double code(double x, double y, double z) {
return 1.0 * x;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = 1.0d0 * x
end function
public static double code(double x, double y, double z) {
return 1.0 * x;
}
def code(x, y, z): return 1.0 * x
function code(x, y, z) return Float64(1.0 * x) end
function tmp = code(x, y, z) tmp = 1.0 * x; end
code[x_, y_, z_] := N[(1.0 * x), $MachinePrecision]
\begin{array}{l}
\\
1 \cdot x
\end{array}
Initial program 95.5%
Taylor expanded in y around 0
lower--.f6465.0
Applied rewrites65.0%
Taylor expanded in z around 0
Applied rewrites40.0%
Final simplification40.0%
(FPCore (x y z)
:precision binary64
(let* ((t_0 (* x (- 1.0 (* (- 1.0 y) z))))
(t_1 (+ x (* (- 1.0 y) (* (- z) x)))))
(if (< t_0 -1.618195973607049e+50)
t_1
(if (< t_0 3.892237649663903e+134) (- (* (* x y) z) (- (* x z) x)) t_1))))
double code(double x, double y, double z) {
double t_0 = x * (1.0 - ((1.0 - y) * z));
double t_1 = x + ((1.0 - y) * (-z * x));
double tmp;
if (t_0 < -1.618195973607049e+50) {
tmp = t_1;
} else if (t_0 < 3.892237649663903e+134) {
tmp = ((x * y) * z) - ((x * z) - x);
} else {
tmp = t_1;
}
return tmp;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: t_0
real(8) :: t_1
real(8) :: tmp
t_0 = x * (1.0d0 - ((1.0d0 - y) * z))
t_1 = x + ((1.0d0 - y) * (-z * x))
if (t_0 < (-1.618195973607049d+50)) then
tmp = t_1
else if (t_0 < 3.892237649663903d+134) then
tmp = ((x * y) * z) - ((x * z) - x)
else
tmp = t_1
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double t_0 = x * (1.0 - ((1.0 - y) * z));
double t_1 = x + ((1.0 - y) * (-z * x));
double tmp;
if (t_0 < -1.618195973607049e+50) {
tmp = t_1;
} else if (t_0 < 3.892237649663903e+134) {
tmp = ((x * y) * z) - ((x * z) - x);
} else {
tmp = t_1;
}
return tmp;
}
def code(x, y, z): t_0 = x * (1.0 - ((1.0 - y) * z)) t_1 = x + ((1.0 - y) * (-z * x)) tmp = 0 if t_0 < -1.618195973607049e+50: tmp = t_1 elif t_0 < 3.892237649663903e+134: tmp = ((x * y) * z) - ((x * z) - x) else: tmp = t_1 return tmp
function code(x, y, z) t_0 = Float64(x * Float64(1.0 - Float64(Float64(1.0 - y) * z))) t_1 = Float64(x + Float64(Float64(1.0 - y) * Float64(Float64(-z) * x))) tmp = 0.0 if (t_0 < -1.618195973607049e+50) tmp = t_1; elseif (t_0 < 3.892237649663903e+134) tmp = Float64(Float64(Float64(x * y) * z) - Float64(Float64(x * z) - x)); else tmp = t_1; end return tmp end
function tmp_2 = code(x, y, z) t_0 = x * (1.0 - ((1.0 - y) * z)); t_1 = x + ((1.0 - y) * (-z * x)); tmp = 0.0; if (t_0 < -1.618195973607049e+50) tmp = t_1; elseif (t_0 < 3.892237649663903e+134) tmp = ((x * y) * z) - ((x * z) - x); else tmp = t_1; end tmp_2 = tmp; end
code[x_, y_, z_] := Block[{t$95$0 = N[(x * N[(1.0 - N[(N[(1.0 - y), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(x + N[(N[(1.0 - y), $MachinePrecision] * N[((-z) * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[Less[t$95$0, -1.618195973607049e+50], t$95$1, If[Less[t$95$0, 3.892237649663903e+134], N[(N[(N[(x * y), $MachinePrecision] * z), $MachinePrecision] - N[(N[(x * z), $MachinePrecision] - x), $MachinePrecision]), $MachinePrecision], t$95$1]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := x \cdot \left(1 - \left(1 - y\right) \cdot z\right)\\
t_1 := x + \left(1 - y\right) \cdot \left(\left(-z\right) \cdot x\right)\\
\mathbf{if}\;t\_0 < -1.618195973607049 \cdot 10^{+50}:\\
\;\;\;\;t\_1\\
\mathbf{elif}\;t\_0 < 3.892237649663903 \cdot 10^{+134}:\\
\;\;\;\;\left(x \cdot y\right) \cdot z - \left(x \cdot z - x\right)\\
\mathbf{else}:\\
\;\;\;\;t\_1\\
\end{array}
\end{array}
herbie shell --seed 2024327
(FPCore (x y z)
:name "Data.Colour.RGBSpace.HSV:hsv from colour-2.3.3, J"
:precision binary64
:alt
(! :herbie-platform default (if (< (* x (- 1 (* (- 1 y) z))) -161819597360704900000000000000000000000000000000000) (+ x (* (- 1 y) (* (- z) x))) (if (< (* x (- 1 (* (- 1 y) z))) 389223764966390300000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (- (* (* x y) z) (- (* x z) x)) (+ x (* (- 1 y) (* (- z) x))))))
(* x (- 1.0 (* (- 1.0 y) z))))