
(FPCore (x y z t) :precision binary64 (+ x (/ (* y (- z x)) t)))
double code(double x, double y, double z, double t) {
return x + ((y * (z - x)) / 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 + ((y * (z - x)) / t)
end function
public static double code(double x, double y, double z, double t) {
return x + ((y * (z - x)) / t);
}
def code(x, y, z, t): return x + ((y * (z - x)) / t)
function code(x, y, z, t) return Float64(x + Float64(Float64(y * Float64(z - x)) / t)) end
function tmp = code(x, y, z, t) tmp = x + ((y * (z - x)) / t); end
code[x_, y_, z_, t_] := N[(x + N[(N[(y * N[(z - x), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{y \cdot \left(z - x\right)}{t}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z t) :precision binary64 (+ x (/ (* y (- z x)) t)))
double code(double x, double y, double z, double t) {
return x + ((y * (z - x)) / 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 + ((y * (z - x)) / t)
end function
public static double code(double x, double y, double z, double t) {
return x + ((y * (z - x)) / t);
}
def code(x, y, z, t): return x + ((y * (z - x)) / t)
function code(x, y, z, t) return Float64(x + Float64(Float64(y * Float64(z - x)) / t)) end
function tmp = code(x, y, z, t) tmp = x + ((y * (z - x)) / t); end
code[x_, y_, z_, t_] := N[(x + N[(N[(y * N[(z - x), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{y \cdot \left(z - x\right)}{t}
\end{array}
(FPCore (x y z t) :precision binary64 (+ x (* (/ y t) (- z x))))
double code(double x, double y, double z, double t) {
return x + ((y / t) * (z - x));
}
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 + ((y / t) * (z - x))
end function
public static double code(double x, double y, double z, double t) {
return x + ((y / t) * (z - x));
}
def code(x, y, z, t): return x + ((y / t) * (z - x))
function code(x, y, z, t) return Float64(x + Float64(Float64(y / t) * Float64(z - x))) end
function tmp = code(x, y, z, t) tmp = x + ((y / t) * (z - x)); end
code[x_, y_, z_, t_] := N[(x + N[(N[(y / t), $MachinePrecision] * N[(z - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{y}{t} \cdot \left(z - x\right)
\end{array}
Initial program 92.1%
associate-*l/98.4%
Simplified98.4%
Final simplification98.4%
(FPCore (x y z t) :precision binary64 (if (or (<= t -8e-75) (not (<= t 8.5e-73))) (+ x (* (/ y t) z)) (* (/ y t) (- z x))))
double code(double x, double y, double z, double t) {
double tmp;
if ((t <= -8e-75) || !(t <= 8.5e-73)) {
tmp = x + ((y / t) * z);
} else {
tmp = (y / t) * (z - x);
}
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 ((t <= (-8d-75)) .or. (.not. (t <= 8.5d-73))) then
tmp = x + ((y / t) * z)
else
tmp = (y / t) * (z - x)
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if ((t <= -8e-75) || !(t <= 8.5e-73)) {
tmp = x + ((y / t) * z);
} else {
tmp = (y / t) * (z - x);
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if (t <= -8e-75) or not (t <= 8.5e-73): tmp = x + ((y / t) * z) else: tmp = (y / t) * (z - x) return tmp
function code(x, y, z, t) tmp = 0.0 if ((t <= -8e-75) || !(t <= 8.5e-73)) tmp = Float64(x + Float64(Float64(y / t) * z)); else tmp = Float64(Float64(y / t) * Float64(z - x)); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if ((t <= -8e-75) || ~((t <= 8.5e-73))) tmp = x + ((y / t) * z); else tmp = (y / t) * (z - x); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[t, -8e-75], N[Not[LessEqual[t, 8.5e-73]], $MachinePrecision]], N[(x + N[(N[(y / t), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision], N[(N[(y / t), $MachinePrecision] * N[(z - x), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;t \leq -8 \cdot 10^{-75} \lor \neg \left(t \leq 8.5 \cdot 10^{-73}\right):\\
\;\;\;\;x + \frac{y}{t} \cdot z\\
\mathbf{else}:\\
\;\;\;\;\frac{y}{t} \cdot \left(z - x\right)\\
\end{array}
\end{array}
if t < -7.9999999999999997e-75 or 8.4999999999999996e-73 < t Initial program 88.7%
associate-*l/99.3%
Simplified99.3%
Taylor expanded in z around inf 85.2%
associate-*l/89.9%
*-commutative89.9%
Simplified89.9%
if -7.9999999999999997e-75 < t < 8.4999999999999996e-73Initial program 98.2%
associate-*l/96.8%
Simplified96.8%
+-commutative96.8%
associate-*l/98.2%
clear-num98.2%
associate-/r/98.3%
fma-def98.3%
Applied egg-rr98.3%
Taylor expanded in t around 0 92.4%
associate-/l*82.5%
Simplified82.5%
associate-/r/90.5%
Applied egg-rr90.5%
Final simplification90.1%
(FPCore (x y z t) :precision binary64 (if (or (<= t -8.5e-75) (not (<= t 7.5e+41))) (+ x (* (/ y t) z)) (/ (* y (- z x)) t)))
double code(double x, double y, double z, double t) {
double tmp;
if ((t <= -8.5e-75) || !(t <= 7.5e+41)) {
tmp = x + ((y / t) * z);
} else {
tmp = (y * (z - x)) / 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 ((t <= (-8.5d-75)) .or. (.not. (t <= 7.5d+41))) then
tmp = x + ((y / t) * z)
else
tmp = (y * (z - x)) / t
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if ((t <= -8.5e-75) || !(t <= 7.5e+41)) {
tmp = x + ((y / t) * z);
} else {
tmp = (y * (z - x)) / t;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if (t <= -8.5e-75) or not (t <= 7.5e+41): tmp = x + ((y / t) * z) else: tmp = (y * (z - x)) / t return tmp
function code(x, y, z, t) tmp = 0.0 if ((t <= -8.5e-75) || !(t <= 7.5e+41)) tmp = Float64(x + Float64(Float64(y / t) * z)); else tmp = Float64(Float64(y * Float64(z - x)) / t); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if ((t <= -8.5e-75) || ~((t <= 7.5e+41))) tmp = x + ((y / t) * z); else tmp = (y * (z - x)) / t; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[t, -8.5e-75], N[Not[LessEqual[t, 7.5e+41]], $MachinePrecision]], N[(x + N[(N[(y / t), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision], N[(N[(y * N[(z - x), $MachinePrecision]), $MachinePrecision] / t), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;t \leq -8.5 \cdot 10^{-75} \lor \neg \left(t \leq 7.5 \cdot 10^{+41}\right):\\
\;\;\;\;x + \frac{y}{t} \cdot z\\
\mathbf{else}:\\
\;\;\;\;\frac{y \cdot \left(z - x\right)}{t}\\
\end{array}
\end{array}
if t < -8.5000000000000001e-75 or 7.50000000000000072e41 < t Initial program 87.2%
associate-*l/99.9%
Simplified99.9%
Taylor expanded in z around inf 87.1%
associate-*l/93.1%
*-commutative93.1%
Simplified93.1%
if -8.5000000000000001e-75 < t < 7.50000000000000072e41Initial program 98.5%
associate-*l/96.5%
Simplified96.5%
+-commutative96.5%
associate-*l/98.5%
clear-num98.4%
associate-/r/98.6%
fma-def98.6%
Applied egg-rr98.6%
Taylor expanded in t around 0 87.9%
Final simplification90.8%
(FPCore (x y z t) :precision binary64 (if (<= t -2.05e+55) x (if (<= t 3.3e+182) (* (/ y t) (- z x)) x)))
double code(double x, double y, double z, double t) {
double tmp;
if (t <= -2.05e+55) {
tmp = x;
} else if (t <= 3.3e+182) {
tmp = (y / t) * (z - x);
} else {
tmp = x;
}
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 (t <= (-2.05d+55)) then
tmp = x
else if (t <= 3.3d+182) then
tmp = (y / t) * (z - x)
else
tmp = x
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (t <= -2.05e+55) {
tmp = x;
} else if (t <= 3.3e+182) {
tmp = (y / t) * (z - x);
} else {
tmp = x;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if t <= -2.05e+55: tmp = x elif t <= 3.3e+182: tmp = (y / t) * (z - x) else: tmp = x return tmp
function code(x, y, z, t) tmp = 0.0 if (t <= -2.05e+55) tmp = x; elseif (t <= 3.3e+182) tmp = Float64(Float64(y / t) * Float64(z - x)); else tmp = x; end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (t <= -2.05e+55) tmp = x; elseif (t <= 3.3e+182) tmp = (y / t) * (z - x); else tmp = x; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[t, -2.05e+55], x, If[LessEqual[t, 3.3e+182], N[(N[(y / t), $MachinePrecision] * N[(z - x), $MachinePrecision]), $MachinePrecision], x]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;t \leq -2.05 \cdot 10^{+55}:\\
\;\;\;\;x\\
\mathbf{elif}\;t \leq 3.3 \cdot 10^{+182}:\\
\;\;\;\;\frac{y}{t} \cdot \left(z - x\right)\\
\mathbf{else}:\\
\;\;\;\;x\\
\end{array}
\end{array}
if t < -2.04999999999999991e55 or 3.3000000000000001e182 < t Initial program 83.5%
associate-*l/99.9%
Simplified99.9%
Taylor expanded in y around 0 78.3%
if -2.04999999999999991e55 < t < 3.3000000000000001e182Initial program 97.7%
associate-*l/97.4%
Simplified97.4%
+-commutative97.4%
associate-*l/97.7%
clear-num97.6%
associate-/r/97.7%
fma-def97.7%
Applied egg-rr97.7%
Taylor expanded in t around 0 80.3%
associate-/l*75.5%
Simplified75.5%
associate-/r/79.7%
Applied egg-rr79.7%
Final simplification79.2%
(FPCore (x y z t) :precision binary64 (if (<= t -8.2e-75) (+ x (* (/ y t) z)) (if (<= t 1.32e-69) (* (/ y t) (- z x)) (+ x (/ y (/ t z))))))
double code(double x, double y, double z, double t) {
double tmp;
if (t <= -8.2e-75) {
tmp = x + ((y / t) * z);
} else if (t <= 1.32e-69) {
tmp = (y / t) * (z - x);
} else {
tmp = x + (y / (t / z));
}
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 (t <= (-8.2d-75)) then
tmp = x + ((y / t) * z)
else if (t <= 1.32d-69) then
tmp = (y / t) * (z - x)
else
tmp = x + (y / (t / z))
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (t <= -8.2e-75) {
tmp = x + ((y / t) * z);
} else if (t <= 1.32e-69) {
tmp = (y / t) * (z - x);
} else {
tmp = x + (y / (t / z));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if t <= -8.2e-75: tmp = x + ((y / t) * z) elif t <= 1.32e-69: tmp = (y / t) * (z - x) else: tmp = x + (y / (t / z)) return tmp
function code(x, y, z, t) tmp = 0.0 if (t <= -8.2e-75) tmp = Float64(x + Float64(Float64(y / t) * z)); elseif (t <= 1.32e-69) tmp = Float64(Float64(y / t) * Float64(z - x)); else tmp = Float64(x + Float64(y / Float64(t / z))); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (t <= -8.2e-75) tmp = x + ((y / t) * z); elseif (t <= 1.32e-69) tmp = (y / t) * (z - x); else tmp = x + (y / (t / z)); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[t, -8.2e-75], N[(x + N[(N[(y / t), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision], If[LessEqual[t, 1.32e-69], N[(N[(y / t), $MachinePrecision] * N[(z - x), $MachinePrecision]), $MachinePrecision], N[(x + N[(y / N[(t / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;t \leq -8.2 \cdot 10^{-75}:\\
\;\;\;\;x + \frac{y}{t} \cdot z\\
\mathbf{elif}\;t \leq 1.32 \cdot 10^{-69}:\\
\;\;\;\;\frac{y}{t} \cdot \left(z - x\right)\\
\mathbf{else}:\\
\;\;\;\;x + \frac{y}{\frac{t}{z}}\\
\end{array}
\end{array}
if t < -8.20000000000000005e-75Initial program 87.4%
associate-*l/99.9%
Simplified99.9%
Taylor expanded in z around inf 89.2%
associate-*l/94.0%
*-commutative94.0%
Simplified94.0%
if -8.20000000000000005e-75 < t < 1.32000000000000007e-69Initial program 98.2%
associate-*l/96.8%
Simplified96.8%
+-commutative96.8%
associate-*l/98.2%
clear-num98.2%
associate-/r/98.3%
fma-def98.3%
Applied egg-rr98.3%
Taylor expanded in t around 0 92.4%
associate-/l*82.5%
Simplified82.5%
associate-/r/90.5%
Applied egg-rr90.5%
if 1.32000000000000007e-69 < t Initial program 89.8%
associate-/l*98.7%
Simplified98.7%
Taylor expanded in z around inf 86.1%
Final simplification90.1%
(FPCore (x y z t) :precision binary64 (if (<= t -1.4e+50) x (if (<= t 9.8e+185) (* y (/ z t)) x)))
double code(double x, double y, double z, double t) {
double tmp;
if (t <= -1.4e+50) {
tmp = x;
} else if (t <= 9.8e+185) {
tmp = y * (z / t);
} else {
tmp = x;
}
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 (t <= (-1.4d+50)) then
tmp = x
else if (t <= 9.8d+185) then
tmp = y * (z / t)
else
tmp = x
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (t <= -1.4e+50) {
tmp = x;
} else if (t <= 9.8e+185) {
tmp = y * (z / t);
} else {
tmp = x;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if t <= -1.4e+50: tmp = x elif t <= 9.8e+185: tmp = y * (z / t) else: tmp = x return tmp
function code(x, y, z, t) tmp = 0.0 if (t <= -1.4e+50) tmp = x; elseif (t <= 9.8e+185) tmp = Float64(y * Float64(z / t)); else tmp = x; end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (t <= -1.4e+50) tmp = x; elseif (t <= 9.8e+185) tmp = y * (z / t); else tmp = x; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[t, -1.4e+50], x, If[LessEqual[t, 9.8e+185], N[(y * N[(z / t), $MachinePrecision]), $MachinePrecision], x]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;t \leq -1.4 \cdot 10^{+50}:\\
\;\;\;\;x\\
\mathbf{elif}\;t \leq 9.8 \cdot 10^{+185}:\\
\;\;\;\;y \cdot \frac{z}{t}\\
\mathbf{else}:\\
\;\;\;\;x\\
\end{array}
\end{array}
if t < -1.3999999999999999e50 or 9.79999999999999968e185 < t Initial program 83.5%
associate-*l/99.9%
Simplified99.9%
Taylor expanded in y around 0 78.3%
if -1.3999999999999999e50 < t < 9.79999999999999968e185Initial program 97.7%
+-commutative97.7%
associate-*r/92.1%
fma-def92.1%
Simplified92.1%
fma-udef92.1%
Applied egg-rr92.1%
add-cube-cbrt91.4%
pow391.4%
fma-def91.4%
Applied egg-rr91.4%
Taylor expanded in x around 0 47.5%
pow-base-147.5%
associate-*r/45.3%
*-lft-identity45.3%
Simplified45.3%
Final simplification58.2%
(FPCore (x y z t) :precision binary64 (if (<= t -2.7e+47) x (if (<= t 3.1e+182) (* (/ y t) z) x)))
double code(double x, double y, double z, double t) {
double tmp;
if (t <= -2.7e+47) {
tmp = x;
} else if (t <= 3.1e+182) {
tmp = (y / t) * z;
} else {
tmp = x;
}
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 (t <= (-2.7d+47)) then
tmp = x
else if (t <= 3.1d+182) then
tmp = (y / t) * z
else
tmp = x
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (t <= -2.7e+47) {
tmp = x;
} else if (t <= 3.1e+182) {
tmp = (y / t) * z;
} else {
tmp = x;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if t <= -2.7e+47: tmp = x elif t <= 3.1e+182: tmp = (y / t) * z else: tmp = x return tmp
function code(x, y, z, t) tmp = 0.0 if (t <= -2.7e+47) tmp = x; elseif (t <= 3.1e+182) tmp = Float64(Float64(y / t) * z); else tmp = x; end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (t <= -2.7e+47) tmp = x; elseif (t <= 3.1e+182) tmp = (y / t) * z; else tmp = x; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[LessEqual[t, -2.7e+47], x, If[LessEqual[t, 3.1e+182], N[(N[(y / t), $MachinePrecision] * z), $MachinePrecision], x]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;t \leq -2.7 \cdot 10^{+47}:\\
\;\;\;\;x\\
\mathbf{elif}\;t \leq 3.1 \cdot 10^{+182}:\\
\;\;\;\;\frac{y}{t} \cdot z\\
\mathbf{else}:\\
\;\;\;\;x\\
\end{array}
\end{array}
if t < -2.69999999999999996e47 or 3.09999999999999996e182 < t Initial program 83.5%
associate-*l/99.9%
Simplified99.9%
Taylor expanded in y around 0 78.3%
if -2.69999999999999996e47 < t < 3.09999999999999996e182Initial program 97.7%
+-commutative97.7%
associate-*r/92.1%
fma-def92.1%
Simplified92.1%
fma-udef92.1%
Applied egg-rr92.1%
add-cube-cbrt91.4%
pow391.4%
fma-def91.4%
Applied egg-rr91.4%
Taylor expanded in x around 0 47.5%
pow-base-147.5%
associate-*r/47.5%
*-lft-identity47.5%
associate-*l/51.1%
*-commutative51.1%
Simplified51.1%
Final simplification61.7%
(FPCore (x y z t) :precision binary64 x)
double code(double x, double y, double z, double t) {
return x;
}
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
end function
public static double code(double x, double y, double z, double t) {
return x;
}
def code(x, y, z, t): return x
function code(x, y, z, t) return x end
function tmp = code(x, y, z, t) tmp = x; end
code[x_, y_, z_, t_] := x
\begin{array}{l}
\\
x
\end{array}
Initial program 92.1%
associate-*l/98.4%
Simplified98.4%
Taylor expanded in y around 0 41.7%
Final simplification41.7%
(FPCore (x y z t) :precision binary64 (- x (+ (* x (/ y t)) (* (- z) (/ y t)))))
double code(double x, double y, double z, double t) {
return x - ((x * (y / t)) + (-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 - ((x * (y / t)) + (-z * (y / t)))
end function
public static double code(double x, double y, double z, double t) {
return x - ((x * (y / t)) + (-z * (y / t)));
}
def code(x, y, z, t): return x - ((x * (y / t)) + (-z * (y / t)))
function code(x, y, z, t) return Float64(x - Float64(Float64(x * Float64(y / t)) + Float64(Float64(-z) * Float64(y / t)))) end
function tmp = code(x, y, z, t) tmp = x - ((x * (y / t)) + (-z * (y / t))); end
code[x_, y_, z_, t_] := N[(x - N[(N[(x * N[(y / t), $MachinePrecision]), $MachinePrecision] + N[((-z) * N[(y / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x - \left(x \cdot \frac{y}{t} + \left(-z\right) \cdot \frac{y}{t}\right)
\end{array}
herbie shell --seed 2023199
(FPCore (x y z t)
:name "Optimisation.CirclePacking:place from circle-packing-0.1.0.4, D"
:precision binary64
:herbie-target
(- x (+ (* x (/ y t)) (* (- z) (/ y t))))
(+ x (/ (* y (- z x)) t)))