
(FPCore (x y z) :precision binary64 (+ 1.0 (/ (* 4.0 (- (+ x (* y 0.25)) z)) y)))
double code(double x, double y, double z) {
return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y);
}
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 + ((4.0d0 * ((x + (y * 0.25d0)) - z)) / y)
end function
public static double code(double x, double y, double z) {
return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y);
}
def code(x, y, z): return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y)
function code(x, y, z) return Float64(1.0 + Float64(Float64(4.0 * Float64(Float64(x + Float64(y * 0.25)) - z)) / y)) end
function tmp = code(x, y, z) tmp = 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y); end
code[x_, y_, z_] := N[(1.0 + N[(N[(4.0 * N[(N[(x + N[(y * 0.25), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]), $MachinePrecision] / y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
1 + \frac{4 \cdot \left(\left(x + y \cdot 0.25\right) - z\right)}{y}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z) :precision binary64 (+ 1.0 (/ (* 4.0 (- (+ x (* y 0.25)) z)) y)))
double code(double x, double y, double z) {
return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y);
}
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 + ((4.0d0 * ((x + (y * 0.25d0)) - z)) / y)
end function
public static double code(double x, double y, double z) {
return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y);
}
def code(x, y, z): return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y)
function code(x, y, z) return Float64(1.0 + Float64(Float64(4.0 * Float64(Float64(x + Float64(y * 0.25)) - z)) / y)) end
function tmp = code(x, y, z) tmp = 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y); end
code[x_, y_, z_] := N[(1.0 + N[(N[(4.0 * N[(N[(x + N[(y * 0.25), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]), $MachinePrecision] / y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
1 + \frac{4 \cdot \left(\left(x + y \cdot 0.25\right) - z\right)}{y}
\end{array}
(FPCore (x y z) :precision binary64 (+ 1.0 (/ (* 4.0 (- (+ x (* y 0.25)) z)) y)))
double code(double x, double y, double z) {
return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y);
}
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 + ((4.0d0 * ((x + (y * 0.25d0)) - z)) / y)
end function
public static double code(double x, double y, double z) {
return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y);
}
def code(x, y, z): return 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y)
function code(x, y, z) return Float64(1.0 + Float64(Float64(4.0 * Float64(Float64(x + Float64(y * 0.25)) - z)) / y)) end
function tmp = code(x, y, z) tmp = 1.0 + ((4.0 * ((x + (y * 0.25)) - z)) / y); end
code[x_, y_, z_] := N[(1.0 + N[(N[(4.0 * N[(N[(x + N[(y * 0.25), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]), $MachinePrecision] / y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
1 + \frac{4 \cdot \left(\left(x + y \cdot 0.25\right) - z\right)}{y}
\end{array}
Initial program 100.0%
(FPCore (x y z)
:precision binary64
(let* ((t_0 (/ (* 4.0 (- (+ x (* y 0.25)) z)) y)) (t_1 (/ x (* y 0.25))))
(if (<= t_0 -2e+302)
(* -4.0 (/ z y))
(if (<= t_0 -1000.0) t_1 (if (<= t_0 1e+20) 2.0 t_1)))))
double code(double x, double y, double z) {
double t_0 = (4.0 * ((x + (y * 0.25)) - z)) / y;
double t_1 = x / (y * 0.25);
double tmp;
if (t_0 <= -2e+302) {
tmp = -4.0 * (z / y);
} else if (t_0 <= -1000.0) {
tmp = t_1;
} else if (t_0 <= 1e+20) {
tmp = 2.0;
} 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 = (4.0d0 * ((x + (y * 0.25d0)) - z)) / y
t_1 = x / (y * 0.25d0)
if (t_0 <= (-2d+302)) then
tmp = (-4.0d0) * (z / y)
else if (t_0 <= (-1000.0d0)) then
tmp = t_1
else if (t_0 <= 1d+20) then
tmp = 2.0d0
else
tmp = t_1
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double t_0 = (4.0 * ((x + (y * 0.25)) - z)) / y;
double t_1 = x / (y * 0.25);
double tmp;
if (t_0 <= -2e+302) {
tmp = -4.0 * (z / y);
} else if (t_0 <= -1000.0) {
tmp = t_1;
} else if (t_0 <= 1e+20) {
tmp = 2.0;
} else {
tmp = t_1;
}
return tmp;
}
def code(x, y, z): t_0 = (4.0 * ((x + (y * 0.25)) - z)) / y t_1 = x / (y * 0.25) tmp = 0 if t_0 <= -2e+302: tmp = -4.0 * (z / y) elif t_0 <= -1000.0: tmp = t_1 elif t_0 <= 1e+20: tmp = 2.0 else: tmp = t_1 return tmp
function code(x, y, z) t_0 = Float64(Float64(4.0 * Float64(Float64(x + Float64(y * 0.25)) - z)) / y) t_1 = Float64(x / Float64(y * 0.25)) tmp = 0.0 if (t_0 <= -2e+302) tmp = Float64(-4.0 * Float64(z / y)); elseif (t_0 <= -1000.0) tmp = t_1; elseif (t_0 <= 1e+20) tmp = 2.0; else tmp = t_1; end return tmp end
function tmp_2 = code(x, y, z) t_0 = (4.0 * ((x + (y * 0.25)) - z)) / y; t_1 = x / (y * 0.25); tmp = 0.0; if (t_0 <= -2e+302) tmp = -4.0 * (z / y); elseif (t_0 <= -1000.0) tmp = t_1; elseif (t_0 <= 1e+20) tmp = 2.0; else tmp = t_1; end tmp_2 = tmp; end
code[x_, y_, z_] := Block[{t$95$0 = N[(N[(4.0 * N[(N[(x + N[(y * 0.25), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]), $MachinePrecision] / y), $MachinePrecision]}, Block[{t$95$1 = N[(x / N[(y * 0.25), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -2e+302], N[(-4.0 * N[(z / y), $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$0, -1000.0], t$95$1, If[LessEqual[t$95$0, 1e+20], 2.0, t$95$1]]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{4 \cdot \left(\left(x + y \cdot 0.25\right) - z\right)}{y}\\
t_1 := \frac{x}{y \cdot 0.25}\\
\mathbf{if}\;t\_0 \leq -2 \cdot 10^{+302}:\\
\;\;\;\;-4 \cdot \frac{z}{y}\\
\mathbf{elif}\;t\_0 \leq -1000:\\
\;\;\;\;t\_1\\
\mathbf{elif}\;t\_0 \leq 10^{+20}:\\
\;\;\;\;2\\
\mathbf{else}:\\
\;\;\;\;t\_1\\
\end{array}
\end{array}
if (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) < -2.0000000000000002e302Initial program 100.0%
Taylor expanded in z around inf
lower-*.f64N/A
lower-/.f6471.6
Applied rewrites71.6%
if -2.0000000000000002e302 < (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) < -1e3 or 1e20 < (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) Initial program 100.0%
Taylor expanded in x around inf
associate-*r/N/A
*-lft-identityN/A
metadata-evalN/A
associate-*r*N/A
times-fracN/A
metadata-evalN/A
*-lft-identityN/A
lower-/.f64N/A
lower-*.f6455.1
Applied rewrites55.1%
if -1e3 < (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) < 1e20Initial program 100.0%
Taylor expanded in y around inf
Applied rewrites94.3%
Final simplification69.3%
(FPCore (x y z)
:precision binary64
(let* ((t_0 (/ (- x z) (* y 0.25)))
(t_1 (/ (* 4.0 (- (+ x (* y 0.25)) z)) y)))
(if (<= t_1 -1e+29) t_0 (if (<= t_1 20.0) (fma -4.0 (/ z y) 2.0) t_0))))
double code(double x, double y, double z) {
double t_0 = (x - z) / (y * 0.25);
double t_1 = (4.0 * ((x + (y * 0.25)) - z)) / y;
double tmp;
if (t_1 <= -1e+29) {
tmp = t_0;
} else if (t_1 <= 20.0) {
tmp = fma(-4.0, (z / y), 2.0);
} else {
tmp = t_0;
}
return tmp;
}
function code(x, y, z) t_0 = Float64(Float64(x - z) / Float64(y * 0.25)) t_1 = Float64(Float64(4.0 * Float64(Float64(x + Float64(y * 0.25)) - z)) / y) tmp = 0.0 if (t_1 <= -1e+29) tmp = t_0; elseif (t_1 <= 20.0) tmp = fma(-4.0, Float64(z / y), 2.0); else tmp = t_0; end return tmp end
code[x_, y_, z_] := Block[{t$95$0 = N[(N[(x - z), $MachinePrecision] / N[(y * 0.25), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(4.0 * N[(N[(x + N[(y * 0.25), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]), $MachinePrecision] / y), $MachinePrecision]}, If[LessEqual[t$95$1, -1e+29], t$95$0, If[LessEqual[t$95$1, 20.0], N[(-4.0 * N[(z / y), $MachinePrecision] + 2.0), $MachinePrecision], t$95$0]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{x - z}{y \cdot 0.25}\\
t_1 := \frac{4 \cdot \left(\left(x + y \cdot 0.25\right) - z\right)}{y}\\
\mathbf{if}\;t\_1 \leq -1 \cdot 10^{+29}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;t\_1 \leq 20:\\
\;\;\;\;\mathsf{fma}\left(-4, \frac{z}{y}, 2\right)\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) < -9.99999999999999914e28 or 20 < (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) Initial program 100.0%
Taylor expanded in y around 0
associate-*r/N/A
*-lft-identityN/A
metadata-evalN/A
associate-*r*N/A
times-fracN/A
metadata-evalN/A
*-lft-identityN/A
lower-/.f64N/A
lower--.f64N/A
lower-*.f64100.0
Applied rewrites100.0%
if -9.99999999999999914e28 < (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) < 20Initial program 100.0%
Taylor expanded in x around 0
+-commutativeN/A
div-subN/A
sub-negN/A
distribute-lft-inN/A
associate-/l*N/A
associate-*r*N/A
metadata-evalN/A
*-lft-identityN/A
*-inversesN/A
distribute-neg-fracN/A
neg-mul-1N/A
associate-*r/N/A
associate-*l/N/A
metadata-evalN/A
associate-*r/N/A
neg-mul-1N/A
distribute-rgt-neg-inN/A
+-commutativeN/A
associate-+l+N/A
Applied rewrites98.4%
Final simplification99.5%
(FPCore (x y z) :precision binary64 (let* ((t_0 (* -4.0 (/ z y))) (t_1 (/ (* 4.0 (- (+ x (* y 0.25)) z)) y))) (if (<= t_1 -1000.0) t_0 (if (<= t_1 2.0) 2.0 t_0))))
double code(double x, double y, double z) {
double t_0 = -4.0 * (z / y);
double t_1 = (4.0 * ((x + (y * 0.25)) - z)) / y;
double tmp;
if (t_1 <= -1000.0) {
tmp = t_0;
} else if (t_1 <= 2.0) {
tmp = 2.0;
} 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) :: t_1
real(8) :: tmp
t_0 = (-4.0d0) * (z / y)
t_1 = (4.0d0 * ((x + (y * 0.25d0)) - z)) / y
if (t_1 <= (-1000.0d0)) then
tmp = t_0
else if (t_1 <= 2.0d0) then
tmp = 2.0d0
else
tmp = t_0
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double t_0 = -4.0 * (z / y);
double t_1 = (4.0 * ((x + (y * 0.25)) - z)) / y;
double tmp;
if (t_1 <= -1000.0) {
tmp = t_0;
} else if (t_1 <= 2.0) {
tmp = 2.0;
} else {
tmp = t_0;
}
return tmp;
}
def code(x, y, z): t_0 = -4.0 * (z / y) t_1 = (4.0 * ((x + (y * 0.25)) - z)) / y tmp = 0 if t_1 <= -1000.0: tmp = t_0 elif t_1 <= 2.0: tmp = 2.0 else: tmp = t_0 return tmp
function code(x, y, z) t_0 = Float64(-4.0 * Float64(z / y)) t_1 = Float64(Float64(4.0 * Float64(Float64(x + Float64(y * 0.25)) - z)) / y) tmp = 0.0 if (t_1 <= -1000.0) tmp = t_0; elseif (t_1 <= 2.0) tmp = 2.0; else tmp = t_0; end return tmp end
function tmp_2 = code(x, y, z) t_0 = -4.0 * (z / y); t_1 = (4.0 * ((x + (y * 0.25)) - z)) / y; tmp = 0.0; if (t_1 <= -1000.0) tmp = t_0; elseif (t_1 <= 2.0) tmp = 2.0; else tmp = t_0; end tmp_2 = tmp; end
code[x_, y_, z_] := Block[{t$95$0 = N[(-4.0 * N[(z / y), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(4.0 * N[(N[(x + N[(y * 0.25), $MachinePrecision]), $MachinePrecision] - z), $MachinePrecision]), $MachinePrecision] / y), $MachinePrecision]}, If[LessEqual[t$95$1, -1000.0], t$95$0, If[LessEqual[t$95$1, 2.0], 2.0, t$95$0]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -4 \cdot \frac{z}{y}\\
t_1 := \frac{4 \cdot \left(\left(x + y \cdot 0.25\right) - z\right)}{y}\\
\mathbf{if}\;t\_1 \leq -1000:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;t\_1 \leq 2:\\
\;\;\;\;2\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) < -1e3 or 2 < (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) Initial program 100.0%
Taylor expanded in z around inf
lower-*.f64N/A
lower-/.f6452.0
Applied rewrites52.0%
if -1e3 < (/.f64 (*.f64 #s(literal 4 binary64) (-.f64 (+.f64 x (*.f64 y #s(literal 1/4 binary64))) z)) y) < 2Initial program 100.0%
Taylor expanded in y around inf
Applied rewrites97.6%
(FPCore (x y z) :precision binary64 (let* ((t_0 (fma -4.0 (/ z y) 2.0))) (if (<= z -5.3e-58) t_0 (if (<= z 1e+88) (fma 4.0 (/ x y) 2.0) t_0))))
double code(double x, double y, double z) {
double t_0 = fma(-4.0, (z / y), 2.0);
double tmp;
if (z <= -5.3e-58) {
tmp = t_0;
} else if (z <= 1e+88) {
tmp = fma(4.0, (x / y), 2.0);
} else {
tmp = t_0;
}
return tmp;
}
function code(x, y, z) t_0 = fma(-4.0, Float64(z / y), 2.0) tmp = 0.0 if (z <= -5.3e-58) tmp = t_0; elseif (z <= 1e+88) tmp = fma(4.0, Float64(x / y), 2.0); else tmp = t_0; end return tmp end
code[x_, y_, z_] := Block[{t$95$0 = N[(-4.0 * N[(z / y), $MachinePrecision] + 2.0), $MachinePrecision]}, If[LessEqual[z, -5.3e-58], t$95$0, If[LessEqual[z, 1e+88], N[(4.0 * N[(x / y), $MachinePrecision] + 2.0), $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(-4, \frac{z}{y}, 2\right)\\
\mathbf{if}\;z \leq -5.3 \cdot 10^{-58}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;z \leq 10^{+88}:\\
\;\;\;\;\mathsf{fma}\left(4, \frac{x}{y}, 2\right)\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if z < -5.3000000000000003e-58 or 9.99999999999999959e87 < z Initial program 100.0%
Taylor expanded in x around 0
+-commutativeN/A
div-subN/A
sub-negN/A
distribute-lft-inN/A
associate-/l*N/A
associate-*r*N/A
metadata-evalN/A
*-lft-identityN/A
*-inversesN/A
distribute-neg-fracN/A
neg-mul-1N/A
associate-*r/N/A
associate-*l/N/A
metadata-evalN/A
associate-*r/N/A
neg-mul-1N/A
distribute-rgt-neg-inN/A
+-commutativeN/A
associate-+l+N/A
Applied rewrites88.1%
if -5.3000000000000003e-58 < z < 9.99999999999999959e87Initial program 100.0%
Taylor expanded in z around 0
+-commutativeN/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
metadata-evalN/A
associate-*r/N/A
*-commutativeN/A
distribute-lft-inN/A
associate-*r/N/A
metadata-evalN/A
/-rgt-identityN/A
times-fracN/A
associate-*r*N/A
metadata-evalN/A
*-lft-identityN/A
*-rgt-identityN/A
*-inversesN/A
associate-*l*N/A
associate-*l/N/A
*-lft-identityN/A
Applied rewrites92.4%
(FPCore (x y z) :precision binary64 (let* ((t_0 (/ x (* y 0.25)))) (if (<= x -1.4e+42) t_0 (if (<= x 8.6e+123) (fma -4.0 (/ z y) 2.0) t_0))))
double code(double x, double y, double z) {
double t_0 = x / (y * 0.25);
double tmp;
if (x <= -1.4e+42) {
tmp = t_0;
} else if (x <= 8.6e+123) {
tmp = fma(-4.0, (z / y), 2.0);
} else {
tmp = t_0;
}
return tmp;
}
function code(x, y, z) t_0 = Float64(x / Float64(y * 0.25)) tmp = 0.0 if (x <= -1.4e+42) tmp = t_0; elseif (x <= 8.6e+123) tmp = fma(-4.0, Float64(z / y), 2.0); else tmp = t_0; end return tmp end
code[x_, y_, z_] := Block[{t$95$0 = N[(x / N[(y * 0.25), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[x, -1.4e+42], t$95$0, If[LessEqual[x, 8.6e+123], N[(-4.0 * N[(z / y), $MachinePrecision] + 2.0), $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{x}{y \cdot 0.25}\\
\mathbf{if}\;x \leq -1.4 \cdot 10^{+42}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;x \leq 8.6 \cdot 10^{+123}:\\
\;\;\;\;\mathsf{fma}\left(-4, \frac{z}{y}, 2\right)\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if x < -1.4e42 or 8.59999999999999972e123 < x Initial program 100.0%
Taylor expanded in x around inf
associate-*r/N/A
*-lft-identityN/A
metadata-evalN/A
associate-*r*N/A
times-fracN/A
metadata-evalN/A
*-lft-identityN/A
lower-/.f64N/A
lower-*.f6475.3
Applied rewrites75.3%
if -1.4e42 < x < 8.59999999999999972e123Initial program 100.0%
Taylor expanded in x around 0
+-commutativeN/A
div-subN/A
sub-negN/A
distribute-lft-inN/A
associate-/l*N/A
associate-*r*N/A
metadata-evalN/A
*-lft-identityN/A
*-inversesN/A
distribute-neg-fracN/A
neg-mul-1N/A
associate-*r/N/A
associate-*l/N/A
metadata-evalN/A
associate-*r/N/A
neg-mul-1N/A
distribute-rgt-neg-inN/A
+-commutativeN/A
associate-+l+N/A
Applied rewrites87.0%
Final simplification82.6%
(FPCore (x y z) :precision binary64 2.0)
double code(double x, double y, double z) {
return 2.0;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = 2.0d0
end function
public static double code(double x, double y, double z) {
return 2.0;
}
def code(x, y, z): return 2.0
function code(x, y, z) return 2.0 end
function tmp = code(x, y, z) tmp = 2.0; end
code[x_, y_, z_] := 2.0
\begin{array}{l}
\\
2
\end{array}
Initial program 100.0%
Taylor expanded in y around inf
Applied rewrites30.1%
herbie shell --seed 2024221
(FPCore (x y z)
:name "Data.Array.Repa.Algorithms.ColorRamp:rampColorHotToCold from repa-algorithms-3.4.0.1, C"
:precision binary64
(+ 1.0 (/ (* 4.0 (- (+ x (* y 0.25)) z)) y)))