
(FPCore (x y z t) :precision binary64 (- (+ (* x (log y)) (* z (log (- 1.0 y)))) t))
double code(double x, double y, double z, double t) {
return ((x * log(y)) + (z * log((1.0 - y)))) - t;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = ((x * log(y)) + (z * log((1.0d0 - y)))) - t
end function
public static double code(double x, double y, double z, double t) {
return ((x * Math.log(y)) + (z * Math.log((1.0 - y)))) - t;
}
def code(x, y, z, t): return ((x * math.log(y)) + (z * math.log((1.0 - y)))) - t
function code(x, y, z, t) return Float64(Float64(Float64(x * log(y)) + Float64(z * log(Float64(1.0 - y)))) - t) end
function tmp = code(x, y, z, t) tmp = ((x * log(y)) + (z * log((1.0 - y)))) - t; end
code[x_, y_, z_, t_] := N[(N[(N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision] + N[(z * N[Log[N[(1.0 - y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]
\begin{array}{l}
\\
\left(x \cdot \log y + z \cdot \log \left(1 - y\right)\right) - t
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 9 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z t) :precision binary64 (- (+ (* x (log y)) (* z (log (- 1.0 y)))) t))
double code(double x, double y, double z, double t) {
return ((x * log(y)) + (z * log((1.0 - y)))) - t;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = ((x * log(y)) + (z * log((1.0d0 - y)))) - t
end function
public static double code(double x, double y, double z, double t) {
return ((x * Math.log(y)) + (z * Math.log((1.0 - y)))) - t;
}
def code(x, y, z, t): return ((x * math.log(y)) + (z * math.log((1.0 - y)))) - t
function code(x, y, z, t) return Float64(Float64(Float64(x * log(y)) + Float64(z * log(Float64(1.0 - y)))) - t) end
function tmp = code(x, y, z, t) tmp = ((x * log(y)) + (z * log((1.0 - y)))) - t; end
code[x_, y_, z_, t_] := N[(N[(N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision] + N[(z * N[Log[N[(1.0 - y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]
\begin{array}{l}
\\
\left(x \cdot \log y + z \cdot \log \left(1 - y\right)\right) - t
\end{array}
(FPCore (x y z t) :precision binary64 (- (fma z (log1p (- y)) (* x (log y))) t))
double code(double x, double y, double z, double t) {
return fma(z, log1p(-y), (x * log(y))) - t;
}
function code(x, y, z, t) return Float64(fma(z, log1p(Float64(-y)), Float64(x * log(y))) - t) end
code[x_, y_, z_, t_] := N[(N[(z * N[Log[1 + (-y)], $MachinePrecision] + N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(z, \mathsf{log1p}\left(-y\right), x \cdot \log y\right) - t
\end{array}
Initial program 82.9%
+-commutative82.9%
fma-def82.9%
sub-neg82.9%
log1p-def99.8%
Simplified99.8%
Final simplification99.8%
(FPCore (x y z t)
:precision binary64
(-
(+
(+
(* -0.5 (* z (* y y)))
(- (* -0.3333333333333333 (* z (pow y 3.0))) (* z y)))
(* x (log y)))
t))
double code(double x, double y, double z, double t) {
return (((-0.5 * (z * (y * y))) + ((-0.3333333333333333 * (z * pow(y, 3.0))) - (z * y))) + (x * log(y))) - t;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = ((((-0.5d0) * (z * (y * y))) + (((-0.3333333333333333d0) * (z * (y ** 3.0d0))) - (z * y))) + (x * log(y))) - t
end function
public static double code(double x, double y, double z, double t) {
return (((-0.5 * (z * (y * y))) + ((-0.3333333333333333 * (z * Math.pow(y, 3.0))) - (z * y))) + (x * Math.log(y))) - t;
}
def code(x, y, z, t): return (((-0.5 * (z * (y * y))) + ((-0.3333333333333333 * (z * math.pow(y, 3.0))) - (z * y))) + (x * math.log(y))) - t
function code(x, y, z, t) return Float64(Float64(Float64(Float64(-0.5 * Float64(z * Float64(y * y))) + Float64(Float64(-0.3333333333333333 * Float64(z * (y ^ 3.0))) - Float64(z * y))) + Float64(x * log(y))) - t) end
function tmp = code(x, y, z, t) tmp = (((-0.5 * (z * (y * y))) + ((-0.3333333333333333 * (z * (y ^ 3.0))) - (z * y))) + (x * log(y))) - t; end
code[x_, y_, z_, t_] := N[(N[(N[(N[(-0.5 * N[(z * N[(y * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.3333333333333333 * N[(z * N[Power[y, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(z * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]
\begin{array}{l}
\\
\left(\left(-0.5 \cdot \left(z \cdot \left(y \cdot y\right)\right) + \left(-0.3333333333333333 \cdot \left(z \cdot {y}^{3}\right) - z \cdot y\right)\right) + x \cdot \log y\right) - t
\end{array}
Initial program 82.9%
Taylor expanded in y around 0 99.5%
expm1-log1p-u91.4%
expm1-udef91.4%
pow291.4%
*-commutative91.4%
Applied egg-rr91.4%
expm1-def91.4%
expm1-log1p99.5%
Simplified99.5%
Final simplification99.5%
(FPCore (x y z t) :precision binary64 (let* ((t_1 (* x (log y)))) (if (or (<= t -8e-51) (not (<= t 8.4e-37))) (- t_1 t) (- t_1 (* z y)))))
double code(double x, double y, double z, double t) {
double t_1 = x * log(y);
double tmp;
if ((t <= -8e-51) || !(t <= 8.4e-37)) {
tmp = t_1 - t;
} else {
tmp = t_1 - (z * y);
}
return tmp;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
real(8) :: t_1
real(8) :: tmp
t_1 = x * log(y)
if ((t <= (-8d-51)) .or. (.not. (t <= 8.4d-37))) then
tmp = t_1 - t
else
tmp = t_1 - (z * y)
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double t_1 = x * Math.log(y);
double tmp;
if ((t <= -8e-51) || !(t <= 8.4e-37)) {
tmp = t_1 - t;
} else {
tmp = t_1 - (z * y);
}
return tmp;
}
def code(x, y, z, t): t_1 = x * math.log(y) tmp = 0 if (t <= -8e-51) or not (t <= 8.4e-37): tmp = t_1 - t else: tmp = t_1 - (z * y) return tmp
function code(x, y, z, t) t_1 = Float64(x * log(y)) tmp = 0.0 if ((t <= -8e-51) || !(t <= 8.4e-37)) tmp = Float64(t_1 - t); else tmp = Float64(t_1 - Float64(z * y)); end return tmp end
function tmp_2 = code(x, y, z, t) t_1 = x * log(y); tmp = 0.0; if ((t <= -8e-51) || ~((t <= 8.4e-37))) tmp = t_1 - t; else tmp = t_1 - (z * y); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := Block[{t$95$1 = N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision]}, If[Or[LessEqual[t, -8e-51], N[Not[LessEqual[t, 8.4e-37]], $MachinePrecision]], N[(t$95$1 - t), $MachinePrecision], N[(t$95$1 - N[(z * y), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_1 := x \cdot \log y\\
\mathbf{if}\;t \leq -8 \cdot 10^{-51} \lor \neg \left(t \leq 8.4 \cdot 10^{-37}\right):\\
\;\;\;\;t_1 - t\\
\mathbf{else}:\\
\;\;\;\;t_1 - z \cdot y\\
\end{array}
\end{array}
if t < -8.0000000000000001e-51 or 8.4000000000000003e-37 < t Initial program 92.5%
Taylor expanded in y around 0 91.2%
if -8.0000000000000001e-51 < t < 8.4000000000000003e-37Initial program 69.2%
Taylor expanded in y around 0 98.1%
+-commutative98.1%
*-commutative98.1%
mul-1-neg98.1%
unsub-neg98.1%
*-commutative98.1%
Simplified98.1%
Taylor expanded in t around 0 91.3%
Final simplification91.2%
(FPCore (x y z t) :precision binary64 (if (or (<= x -2.1e-56) (not (<= x 5.6e+27))) (- (* x (log y)) t) (- (* z (log1p (- y))) t)))
double code(double x, double y, double z, double t) {
double tmp;
if ((x <= -2.1e-56) || !(x <= 5.6e+27)) {
tmp = (x * log(y)) - t;
} else {
tmp = (z * log1p(-y)) - t;
}
return tmp;
}
public static double code(double x, double y, double z, double t) {
double tmp;
if ((x <= -2.1e-56) || !(x <= 5.6e+27)) {
tmp = (x * Math.log(y)) - t;
} else {
tmp = (z * Math.log1p(-y)) - t;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if (x <= -2.1e-56) or not (x <= 5.6e+27): tmp = (x * math.log(y)) - t else: tmp = (z * math.log1p(-y)) - t return tmp
function code(x, y, z, t) tmp = 0.0 if ((x <= -2.1e-56) || !(x <= 5.6e+27)) tmp = Float64(Float64(x * log(y)) - t); else tmp = Float64(Float64(z * log1p(Float64(-y))) - t); end return tmp end
code[x_, y_, z_, t_] := If[Or[LessEqual[x, -2.1e-56], N[Not[LessEqual[x, 5.6e+27]], $MachinePrecision]], N[(N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision], N[(N[(z * N[Log[1 + (-y)], $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -2.1 \cdot 10^{-56} \lor \neg \left(x \leq 5.6 \cdot 10^{+27}\right):\\
\;\;\;\;x \cdot \log y - t\\
\mathbf{else}:\\
\;\;\;\;z \cdot \mathsf{log1p}\left(-y\right) - t\\
\end{array}
\end{array}
if x < -2.10000000000000006e-56 or 5.5999999999999999e27 < x Initial program 93.4%
Taylor expanded in y around 0 92.9%
if -2.10000000000000006e-56 < x < 5.5999999999999999e27Initial program 72.0%
Taylor expanded in x around 0 61.8%
sub-neg61.8%
mul-1-neg61.8%
log1p-def89.3%
mul-1-neg89.3%
Simplified89.3%
Final simplification91.1%
(FPCore (x y z t) :precision binary64 (if (or (<= x -2.3e-61) (not (<= x 5e+27))) (- (* x (log y)) t) (- (* z (- y)) t)))
double code(double x, double y, double z, double t) {
double tmp;
if ((x <= -2.3e-61) || !(x <= 5e+27)) {
tmp = (x * log(y)) - t;
} else {
tmp = (z * -y) - t;
}
return tmp;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
real(8) :: tmp
if ((x <= (-2.3d-61)) .or. (.not. (x <= 5d+27))) then
tmp = (x * log(y)) - t
else
tmp = (z * -y) - t
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if ((x <= -2.3e-61) || !(x <= 5e+27)) {
tmp = (x * Math.log(y)) - t;
} else {
tmp = (z * -y) - t;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if (x <= -2.3e-61) or not (x <= 5e+27): tmp = (x * math.log(y)) - t else: tmp = (z * -y) - t return tmp
function code(x, y, z, t) tmp = 0.0 if ((x <= -2.3e-61) || !(x <= 5e+27)) tmp = Float64(Float64(x * log(y)) - t); else tmp = Float64(Float64(z * Float64(-y)) - t); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if ((x <= -2.3e-61) || ~((x <= 5e+27))) tmp = (x * log(y)) - t; else tmp = (z * -y) - t; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[x, -2.3e-61], N[Not[LessEqual[x, 5e+27]], $MachinePrecision]], N[(N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision], N[(N[(z * (-y)), $MachinePrecision] - t), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -2.3 \cdot 10^{-61} \lor \neg \left(x \leq 5 \cdot 10^{+27}\right):\\
\;\;\;\;x \cdot \log y - t\\
\mathbf{else}:\\
\;\;\;\;z \cdot \left(-y\right) - t\\
\end{array}
\end{array}
if x < -2.29999999999999992e-61 or 4.99999999999999979e27 < x Initial program 93.4%
Taylor expanded in y around 0 92.9%
if -2.29999999999999992e-61 < x < 4.99999999999999979e27Initial program 72.0%
Taylor expanded in y around 0 98.0%
+-commutative98.0%
*-commutative98.0%
mul-1-neg98.0%
unsub-neg98.0%
*-commutative98.0%
Simplified98.0%
Taylor expanded in x around 0 87.4%
Final simplification90.2%
(FPCore (x y z t) :precision binary64 (- (- (* x (log y)) (* z y)) t))
double code(double x, double y, double z, double t) {
return ((x * log(y)) - (z * y)) - t;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = ((x * log(y)) - (z * y)) - t
end function
public static double code(double x, double y, double z, double t) {
return ((x * Math.log(y)) - (z * y)) - t;
}
def code(x, y, z, t): return ((x * math.log(y)) - (z * y)) - t
function code(x, y, z, t) return Float64(Float64(Float64(x * log(y)) - Float64(z * y)) - t) end
function tmp = code(x, y, z, t) tmp = ((x * log(y)) - (z * y)) - t; end
code[x_, y_, z_, t_] := N[(N[(N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision] - N[(z * y), $MachinePrecision]), $MachinePrecision] - t), $MachinePrecision]
\begin{array}{l}
\\
\left(x \cdot \log y - z \cdot y\right) - t
\end{array}
Initial program 82.9%
Taylor expanded in y around 0 98.7%
+-commutative98.7%
*-commutative98.7%
mul-1-neg98.7%
unsub-neg98.7%
*-commutative98.7%
Simplified98.7%
Final simplification98.7%
(FPCore (x y z t) :precision binary64 (if (or (<= x -4e+82) (not (<= x 4.6e+42))) (* x (log y)) (- (* z (- y)) t)))
double code(double x, double y, double z, double t) {
double tmp;
if ((x <= -4e+82) || !(x <= 4.6e+42)) {
tmp = x * log(y);
} else {
tmp = (z * -y) - t;
}
return tmp;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
real(8) :: tmp
if ((x <= (-4d+82)) .or. (.not. (x <= 4.6d+42))) then
tmp = x * log(y)
else
tmp = (z * -y) - t
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if ((x <= -4e+82) || !(x <= 4.6e+42)) {
tmp = x * Math.log(y);
} else {
tmp = (z * -y) - t;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if (x <= -4e+82) or not (x <= 4.6e+42): tmp = x * math.log(y) else: tmp = (z * -y) - t return tmp
function code(x, y, z, t) tmp = 0.0 if ((x <= -4e+82) || !(x <= 4.6e+42)) tmp = Float64(x * log(y)); else tmp = Float64(Float64(z * Float64(-y)) - t); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if ((x <= -4e+82) || ~((x <= 4.6e+42))) tmp = x * log(y); else tmp = (z * -y) - t; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[x, -4e+82], N[Not[LessEqual[x, 4.6e+42]], $MachinePrecision]], N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision], N[(N[(z * (-y)), $MachinePrecision] - t), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -4 \cdot 10^{+82} \lor \neg \left(x \leq 4.6 \cdot 10^{+42}\right):\\
\;\;\;\;x \cdot \log y\\
\mathbf{else}:\\
\;\;\;\;z \cdot \left(-y\right) - t\\
\end{array}
\end{array}
if x < -3.9999999999999999e82 or 4.6e42 < x Initial program 95.9%
Taylor expanded in y around 0 99.6%
+-commutative99.6%
*-commutative99.6%
mul-1-neg99.6%
unsub-neg99.6%
*-commutative99.6%
Simplified99.6%
Taylor expanded in x around inf 86.0%
if -3.9999999999999999e82 < x < 4.6e42Initial program 74.5%
Taylor expanded in y around 0 98.0%
+-commutative98.0%
*-commutative98.0%
mul-1-neg98.0%
unsub-neg98.0%
*-commutative98.0%
Simplified98.0%
Taylor expanded in x around 0 82.5%
Final simplification83.9%
(FPCore (x y z t) :precision binary64 (- (* z (- y)) t))
double code(double x, double y, double z, double t) {
return (z * -y) - t;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = (z * -y) - t
end function
public static double code(double x, double y, double z, double t) {
return (z * -y) - t;
}
def code(x, y, z, t): return (z * -y) - t
function code(x, y, z, t) return Float64(Float64(z * Float64(-y)) - t) end
function tmp = code(x, y, z, t) tmp = (z * -y) - t; end
code[x_, y_, z_, t_] := N[(N[(z * (-y)), $MachinePrecision] - t), $MachinePrecision]
\begin{array}{l}
\\
z \cdot \left(-y\right) - t
\end{array}
Initial program 82.9%
Taylor expanded in y around 0 98.7%
+-commutative98.7%
*-commutative98.7%
mul-1-neg98.7%
unsub-neg98.7%
*-commutative98.7%
Simplified98.7%
Taylor expanded in x around 0 55.7%
Final simplification55.7%
(FPCore (x y z t) :precision binary64 (- t))
double code(double x, double y, double z, double t) {
return -t;
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = -t
end function
public static double code(double x, double y, double z, double t) {
return -t;
}
def code(x, y, z, t): return -t
function code(x, y, z, t) return Float64(-t) end
function tmp = code(x, y, z, t) tmp = -t; end
code[x_, y_, z_, t_] := (-t)
\begin{array}{l}
\\
-t
\end{array}
Initial program 82.9%
Taylor expanded in t around inf 38.7%
mul-1-neg38.7%
Simplified38.7%
Final simplification38.7%
(FPCore (x y z t)
:precision binary64
(-
(*
(- z)
(+
(+ (* 0.5 (* y y)) y)
(* (/ 0.3333333333333333 (* 1.0 (* 1.0 1.0))) (* y (* y y)))))
(- t (* x (log y)))))
double code(double x, double y, double z, double t) {
return (-z * (((0.5 * (y * y)) + y) + ((0.3333333333333333 / (1.0 * (1.0 * 1.0))) * (y * (y * y))))) - (t - (x * log(y)));
}
real(8) function code(x, y, z, t)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8), intent (in) :: t
code = (-z * (((0.5d0 * (y * y)) + y) + ((0.3333333333333333d0 / (1.0d0 * (1.0d0 * 1.0d0))) * (y * (y * y))))) - (t - (x * log(y)))
end function
public static double code(double x, double y, double z, double t) {
return (-z * (((0.5 * (y * y)) + y) + ((0.3333333333333333 / (1.0 * (1.0 * 1.0))) * (y * (y * y))))) - (t - (x * Math.log(y)));
}
def code(x, y, z, t): return (-z * (((0.5 * (y * y)) + y) + ((0.3333333333333333 / (1.0 * (1.0 * 1.0))) * (y * (y * y))))) - (t - (x * math.log(y)))
function code(x, y, z, t) return Float64(Float64(Float64(-z) * Float64(Float64(Float64(0.5 * Float64(y * y)) + y) + Float64(Float64(0.3333333333333333 / Float64(1.0 * Float64(1.0 * 1.0))) * Float64(y * Float64(y * y))))) - Float64(t - Float64(x * log(y)))) end
function tmp = code(x, y, z, t) tmp = (-z * (((0.5 * (y * y)) + y) + ((0.3333333333333333 / (1.0 * (1.0 * 1.0))) * (y * (y * y))))) - (t - (x * log(y))); end
code[x_, y_, z_, t_] := N[(N[((-z) * N[(N[(N[(0.5 * N[(y * y), $MachinePrecision]), $MachinePrecision] + y), $MachinePrecision] + N[(N[(0.3333333333333333 / N[(1.0 * N[(1.0 * 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(y * N[(y * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(t - N[(x * N[Log[y], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(-z\right) \cdot \left(\left(0.5 \cdot \left(y \cdot y\right) + y\right) + \frac{0.3333333333333333}{1 \cdot \left(1 \cdot 1\right)} \cdot \left(y \cdot \left(y \cdot y\right)\right)\right) - \left(t - x \cdot \log y\right)
\end{array}
herbie shell --seed 2023195
(FPCore (x y z t)
:name "Numeric.SpecFunctions:invIncompleteBetaWorker from math-functions-0.1.5.2, B"
:precision binary64
:herbie-target
(- (* (- z) (+ (+ (* 0.5 (* y y)) y) (* (/ 0.3333333333333333 (* 1.0 (* 1.0 1.0))) (* y (* y y))))) (- t (* x (log y))))
(- (+ (* x (log y)) (* z (log (- 1.0 y)))) t))