
(FPCore (x y z t) :precision binary64 (+ x (* (- y x) (/ z t))))
double code(double x, double y, double z, double t) {
return x + ((y - x) * (z / 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 - x) * (z / t))
end function
public static double code(double x, double y, double z, double t) {
return x + ((y - x) * (z / t));
}
def code(x, y, z, t): return x + ((y - x) * (z / t))
function code(x, y, z, t) return Float64(x + Float64(Float64(y - x) * Float64(z / t))) end
function tmp = code(x, y, z, t) tmp = x + ((y - x) * (z / t)); end
code[x_, y_, z_, t_] := N[(x + N[(N[(y - x), $MachinePrecision] * N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \left(y - x\right) \cdot \frac{z}{t}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z t) :precision binary64 (+ x (* (- y x) (/ z t))))
double code(double x, double y, double z, double t) {
return x + ((y - x) * (z / 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 - x) * (z / t))
end function
public static double code(double x, double y, double z, double t) {
return x + ((y - x) * (z / t));
}
def code(x, y, z, t): return x + ((y - x) * (z / t))
function code(x, y, z, t) return Float64(x + Float64(Float64(y - x) * Float64(z / t))) end
function tmp = code(x, y, z, t) tmp = x + ((y - x) * (z / t)); end
code[x_, y_, z_, t_] := N[(x + N[(N[(y - x), $MachinePrecision] * N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \left(y - x\right) \cdot \frac{z}{t}
\end{array}
(FPCore (x y z t) :precision binary64 (+ x (/ (- y x) (/ t z))))
double code(double x, double y, double z, double t) {
return x + ((y - x) / (t / z));
}
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 - x) / (t / z))
end function
public static double code(double x, double y, double z, double t) {
return x + ((y - x) / (t / z));
}
def code(x, y, z, t): return x + ((y - x) / (t / z))
function code(x, y, z, t) return Float64(x + Float64(Float64(y - x) / Float64(t / z))) end
function tmp = code(x, y, z, t) tmp = x + ((y - x) / (t / z)); end
code[x_, y_, z_, t_] := N[(x + N[(N[(y - x), $MachinePrecision] / N[(t / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{y - x}{\frac{t}{z}}
\end{array}
Initial program 97.6%
clear-num97.6%
un-div-inv97.7%
Applied egg-rr97.7%
Final simplification97.7%
(FPCore (x y z t) :precision binary64 (if (or (<= (/ z t) -5e-45) (not (<= (/ z t) 2e-15))) (* (- y x) (/ z t)) x))
double code(double x, double y, double z, double t) {
double tmp;
if (((z / t) <= -5e-45) || !((z / t) <= 2e-15)) {
tmp = (y - x) * (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 (((z / t) <= (-5d-45)) .or. (.not. ((z / t) <= 2d-15))) then
tmp = (y - x) * (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 (((z / t) <= -5e-45) || !((z / t) <= 2e-15)) {
tmp = (y - x) * (z / t);
} else {
tmp = x;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if ((z / t) <= -5e-45) or not ((z / t) <= 2e-15): tmp = (y - x) * (z / t) else: tmp = x return tmp
function code(x, y, z, t) tmp = 0.0 if ((Float64(z / t) <= -5e-45) || !(Float64(z / t) <= 2e-15)) tmp = Float64(Float64(y - x) * Float64(z / t)); else tmp = x; end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (((z / t) <= -5e-45) || ~(((z / t) <= 2e-15))) tmp = (y - x) * (z / t); else tmp = x; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[N[(z / t), $MachinePrecision], -5e-45], N[Not[LessEqual[N[(z / t), $MachinePrecision], 2e-15]], $MachinePrecision]], N[(N[(y - x), $MachinePrecision] * N[(z / t), $MachinePrecision]), $MachinePrecision], x]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{z}{t} \leq -5 \cdot 10^{-45} \lor \neg \left(\frac{z}{t} \leq 2 \cdot 10^{-15}\right):\\
\;\;\;\;\left(y - x\right) \cdot \frac{z}{t}\\
\mathbf{else}:\\
\;\;\;\;x\\
\end{array}
\end{array}
if (/.f64 z t) < -4.99999999999999976e-45 or 2.0000000000000002e-15 < (/.f64 z t) Initial program 97.7%
Taylor expanded in z around inf 81.4%
sub-div88.0%
associate-/r/93.7%
Applied egg-rr93.7%
Taylor expanded in y around 0 78.0%
fma-def78.0%
*-commutative78.0%
associate-*r/76.1%
fma-def76.1%
neg-mul-176.1%
+-commutative76.1%
sub-neg76.1%
associate-*r/78.0%
associate-/l*76.1%
associate-/l*73.8%
div-sub93.7%
associate-/l*90.6%
associate-*r/93.6%
Simplified93.6%
if -4.99999999999999976e-45 < (/.f64 z t) < 2.0000000000000002e-15Initial program 97.6%
Taylor expanded in z around 0 85.9%
Final simplification90.0%
(FPCore (x y z t) :precision binary64 (if (or (<= (/ z t) -2.0) (not (<= (/ z t) 0.1))) (* (- y x) (/ z t)) (+ x (* y (/ z t)))))
double code(double x, double y, double z, double t) {
double tmp;
if (((z / t) <= -2.0) || !((z / t) <= 0.1)) {
tmp = (y - x) * (z / t);
} else {
tmp = x + (y * (z / 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 (((z / t) <= (-2.0d0)) .or. (.not. ((z / t) <= 0.1d0))) then
tmp = (y - x) * (z / t)
else
tmp = x + (y * (z / t))
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (((z / t) <= -2.0) || !((z / t) <= 0.1)) {
tmp = (y - x) * (z / t);
} else {
tmp = x + (y * (z / t));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if ((z / t) <= -2.0) or not ((z / t) <= 0.1): tmp = (y - x) * (z / t) else: tmp = x + (y * (z / t)) return tmp
function code(x, y, z, t) tmp = 0.0 if ((Float64(z / t) <= -2.0) || !(Float64(z / t) <= 0.1)) tmp = Float64(Float64(y - x) * Float64(z / t)); else tmp = Float64(x + Float64(y * Float64(z / t))); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (((z / t) <= -2.0) || ~(((z / t) <= 0.1))) tmp = (y - x) * (z / t); else tmp = x + (y * (z / t)); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[N[(z / t), $MachinePrecision], -2.0], N[Not[LessEqual[N[(z / t), $MachinePrecision], 0.1]], $MachinePrecision]], N[(N[(y - x), $MachinePrecision] * N[(z / t), $MachinePrecision]), $MachinePrecision], N[(x + N[(y * N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{z}{t} \leq -2 \lor \neg \left(\frac{z}{t} \leq 0.1\right):\\
\;\;\;\;\left(y - x\right) \cdot \frac{z}{t}\\
\mathbf{else}:\\
\;\;\;\;x + y \cdot \frac{z}{t}\\
\end{array}
\end{array}
if (/.f64 z t) < -2 or 0.10000000000000001 < (/.f64 z t) Initial program 97.4%
Taylor expanded in z around inf 85.0%
sub-div92.2%
associate-/r/96.8%
Applied egg-rr96.8%
Taylor expanded in y around 0 80.5%
fma-def80.5%
*-commutative80.5%
associate-*r/77.5%
fma-def77.5%
neg-mul-177.5%
+-commutative77.5%
sub-neg77.5%
associate-*r/80.5%
associate-/l*77.6%
associate-/l*75.0%
div-sub96.8%
associate-/l*94.2%
associate-*r/96.7%
Simplified96.7%
if -2 < (/.f64 z t) < 0.10000000000000001Initial program 97.8%
Taylor expanded in y around inf 93.9%
associate-*r/95.7%
Simplified95.7%
Final simplification96.2%
(FPCore (x y z t) :precision binary64 (if (or (<= (/ z t) -2.0) (not (<= (/ z t) 0.1))) (/ (- y x) (/ t z)) (+ x (* y (/ z t)))))
double code(double x, double y, double z, double t) {
double tmp;
if (((z / t) <= -2.0) || !((z / t) <= 0.1)) {
tmp = (y - x) / (t / z);
} else {
tmp = x + (y * (z / 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 (((z / t) <= (-2.0d0)) .or. (.not. ((z / t) <= 0.1d0))) then
tmp = (y - x) / (t / z)
else
tmp = x + (y * (z / t))
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double tmp;
if (((z / t) <= -2.0) || !((z / t) <= 0.1)) {
tmp = (y - x) / (t / z);
} else {
tmp = x + (y * (z / t));
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if ((z / t) <= -2.0) or not ((z / t) <= 0.1): tmp = (y - x) / (t / z) else: tmp = x + (y * (z / t)) return tmp
function code(x, y, z, t) tmp = 0.0 if ((Float64(z / t) <= -2.0) || !(Float64(z / t) <= 0.1)) tmp = Float64(Float64(y - x) / Float64(t / z)); else tmp = Float64(x + Float64(y * Float64(z / t))); end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (((z / t) <= -2.0) || ~(((z / t) <= 0.1))) tmp = (y - x) / (t / z); else tmp = x + (y * (z / t)); end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[N[(z / t), $MachinePrecision], -2.0], N[Not[LessEqual[N[(z / t), $MachinePrecision], 0.1]], $MachinePrecision]], N[(N[(y - x), $MachinePrecision] / N[(t / z), $MachinePrecision]), $MachinePrecision], N[(x + N[(y * N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{z}{t} \leq -2 \lor \neg \left(\frac{z}{t} \leq 0.1\right):\\
\;\;\;\;\frac{y - x}{\frac{t}{z}}\\
\mathbf{else}:\\
\;\;\;\;x + y \cdot \frac{z}{t}\\
\end{array}
\end{array}
if (/.f64 z t) < -2 or 0.10000000000000001 < (/.f64 z t) Initial program 97.4%
Taylor expanded in z around inf 85.0%
sub-div92.2%
associate-/r/96.8%
Applied egg-rr96.8%
if -2 < (/.f64 z t) < 0.10000000000000001Initial program 97.8%
Taylor expanded in y around inf 93.9%
associate-*r/95.7%
Simplified95.7%
Final simplification96.2%
(FPCore (x y z t) :precision binary64 (if (or (<= (/ z t) -5e-45) (not (<= (/ z t) 2e-15))) (* y (/ z t)) x))
double code(double x, double y, double z, double t) {
double tmp;
if (((z / t) <= -5e-45) || !((z / t) <= 2e-15)) {
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 (((z / t) <= (-5d-45)) .or. (.not. ((z / t) <= 2d-15))) 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 (((z / t) <= -5e-45) || !((z / t) <= 2e-15)) {
tmp = y * (z / t);
} else {
tmp = x;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if ((z / t) <= -5e-45) or not ((z / t) <= 2e-15): tmp = y * (z / t) else: tmp = x return tmp
function code(x, y, z, t) tmp = 0.0 if ((Float64(z / t) <= -5e-45) || !(Float64(z / t) <= 2e-15)) 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 (((z / t) <= -5e-45) || ~(((z / t) <= 2e-15))) tmp = y * (z / t); else tmp = x; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[N[(z / t), $MachinePrecision], -5e-45], N[Not[LessEqual[N[(z / t), $MachinePrecision], 2e-15]], $MachinePrecision]], N[(y * N[(z / t), $MachinePrecision]), $MachinePrecision], x]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{z}{t} \leq -5 \cdot 10^{-45} \lor \neg \left(\frac{z}{t} \leq 2 \cdot 10^{-15}\right):\\
\;\;\;\;y \cdot \frac{z}{t}\\
\mathbf{else}:\\
\;\;\;\;x\\
\end{array}
\end{array}
if (/.f64 z t) < -4.99999999999999976e-45 or 2.0000000000000002e-15 < (/.f64 z t) Initial program 97.7%
Taylor expanded in z around inf 81.4%
sub-div88.0%
associate-/r/93.7%
Applied egg-rr93.7%
Taylor expanded in y around inf 57.8%
associate-*r/62.0%
Simplified62.0%
if -4.99999999999999976e-45 < (/.f64 z t) < 2.0000000000000002e-15Initial program 97.6%
Taylor expanded in z around 0 85.9%
Final simplification73.2%
(FPCore (x y z t) :precision binary64 (if (or (<= (/ z t) -5e-45) (not (<= (/ z t) 2e-15))) (/ y (/ t z)) x))
double code(double x, double y, double z, double t) {
double tmp;
if (((z / t) <= -5e-45) || !((z / t) <= 2e-15)) {
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 (((z / t) <= (-5d-45)) .or. (.not. ((z / t) <= 2d-15))) 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 (((z / t) <= -5e-45) || !((z / t) <= 2e-15)) {
tmp = y / (t / z);
} else {
tmp = x;
}
return tmp;
}
def code(x, y, z, t): tmp = 0 if ((z / t) <= -5e-45) or not ((z / t) <= 2e-15): tmp = y / (t / z) else: tmp = x return tmp
function code(x, y, z, t) tmp = 0.0 if ((Float64(z / t) <= -5e-45) || !(Float64(z / t) <= 2e-15)) tmp = Float64(y / Float64(t / z)); else tmp = x; end return tmp end
function tmp_2 = code(x, y, z, t) tmp = 0.0; if (((z / t) <= -5e-45) || ~(((z / t) <= 2e-15))) tmp = y / (t / z); else tmp = x; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := If[Or[LessEqual[N[(z / t), $MachinePrecision], -5e-45], N[Not[LessEqual[N[(z / t), $MachinePrecision], 2e-15]], $MachinePrecision]], N[(y / N[(t / z), $MachinePrecision]), $MachinePrecision], x]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{z}{t} \leq -5 \cdot 10^{-45} \lor \neg \left(\frac{z}{t} \leq 2 \cdot 10^{-15}\right):\\
\;\;\;\;\frac{y}{\frac{t}{z}}\\
\mathbf{else}:\\
\;\;\;\;x\\
\end{array}
\end{array}
if (/.f64 z t) < -4.99999999999999976e-45 or 2.0000000000000002e-15 < (/.f64 z t) Initial program 97.7%
Taylor expanded in z around inf 81.4%
sub-div88.0%
associate-/r/93.7%
Applied egg-rr93.7%
Taylor expanded in y around inf 57.8%
associate-*r/62.0%
Simplified62.0%
clear-num61.9%
div-inv62.0%
Applied egg-rr62.0%
if -4.99999999999999976e-45 < (/.f64 z t) < 2.0000000000000002e-15Initial program 97.6%
Taylor expanded in z around 0 85.9%
Final simplification73.2%
(FPCore (x y z t) :precision binary64 (+ x (* (- y x) (/ z t))))
double code(double x, double y, double z, double t) {
return x + ((y - x) * (z / 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 - x) * (z / t))
end function
public static double code(double x, double y, double z, double t) {
return x + ((y - x) * (z / t));
}
def code(x, y, z, t): return x + ((y - x) * (z / t))
function code(x, y, z, t) return Float64(x + Float64(Float64(y - x) * Float64(z / t))) end
function tmp = code(x, y, z, t) tmp = x + ((y - x) * (z / t)); end
code[x_, y_, z_, t_] := N[(x + N[(N[(y - x), $MachinePrecision] * N[(z / t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \left(y - x\right) \cdot \frac{z}{t}
\end{array}
Initial program 97.6%
Final simplification97.6%
(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 97.6%
Taylor expanded in z around 0 42.7%
Final simplification42.7%
(FPCore (x y z t)
:precision binary64
(let* ((t_1 (* (- y x) (/ z t))) (t_2 (+ x (/ (- y x) (/ t z)))))
(if (< t_1 -1013646692435.8867)
t_2
(if (< t_1 0.0) (+ x (/ (* (- y x) z) t)) t_2))))
double code(double x, double y, double z, double t) {
double t_1 = (y - x) * (z / t);
double t_2 = x + ((y - x) / (t / z));
double tmp;
if (t_1 < -1013646692435.8867) {
tmp = t_2;
} else if (t_1 < 0.0) {
tmp = x + (((y - x) * z) / t);
} else {
tmp = t_2;
}
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) :: t_2
real(8) :: tmp
t_1 = (y - x) * (z / t)
t_2 = x + ((y - x) / (t / z))
if (t_1 < (-1013646692435.8867d0)) then
tmp = t_2
else if (t_1 < 0.0d0) then
tmp = x + (((y - x) * z) / t)
else
tmp = t_2
end if
code = tmp
end function
public static double code(double x, double y, double z, double t) {
double t_1 = (y - x) * (z / t);
double t_2 = x + ((y - x) / (t / z));
double tmp;
if (t_1 < -1013646692435.8867) {
tmp = t_2;
} else if (t_1 < 0.0) {
tmp = x + (((y - x) * z) / t);
} else {
tmp = t_2;
}
return tmp;
}
def code(x, y, z, t): t_1 = (y - x) * (z / t) t_2 = x + ((y - x) / (t / z)) tmp = 0 if t_1 < -1013646692435.8867: tmp = t_2 elif t_1 < 0.0: tmp = x + (((y - x) * z) / t) else: tmp = t_2 return tmp
function code(x, y, z, t) t_1 = Float64(Float64(y - x) * Float64(z / t)) t_2 = Float64(x + Float64(Float64(y - x) / Float64(t / z))) tmp = 0.0 if (t_1 < -1013646692435.8867) tmp = t_2; elseif (t_1 < 0.0) tmp = Float64(x + Float64(Float64(Float64(y - x) * z) / t)); else tmp = t_2; end return tmp end
function tmp_2 = code(x, y, z, t) t_1 = (y - x) * (z / t); t_2 = x + ((y - x) / (t / z)); tmp = 0.0; if (t_1 < -1013646692435.8867) tmp = t_2; elseif (t_1 < 0.0) tmp = x + (((y - x) * z) / t); else tmp = t_2; end tmp_2 = tmp; end
code[x_, y_, z_, t_] := Block[{t$95$1 = N[(N[(y - x), $MachinePrecision] * N[(z / t), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(x + N[(N[(y - x), $MachinePrecision] / N[(t / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[Less[t$95$1, -1013646692435.8867], t$95$2, If[Less[t$95$1, 0.0], N[(x + N[(N[(N[(y - x), $MachinePrecision] * z), $MachinePrecision] / t), $MachinePrecision]), $MachinePrecision], t$95$2]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \left(y - x\right) \cdot \frac{z}{t}\\
t_2 := x + \frac{y - x}{\frac{t}{z}}\\
\mathbf{if}\;t_1 < -1013646692435.8867:\\
\;\;\;\;t_2\\
\mathbf{elif}\;t_1 < 0:\\
\;\;\;\;x + \frac{\left(y - x\right) \cdot z}{t}\\
\mathbf{else}:\\
\;\;\;\;t_2\\
\end{array}
\end{array}
herbie shell --seed 2023181
(FPCore (x y z t)
:name "Graphics.Rendering.Plot.Render.Plot.Axis:tickPosition from plot-0.2.3.4"
:precision binary64
:herbie-target
(if (< (* (- y x) (/ z t)) -1013646692435.8867) (+ x (/ (- y x) (/ t z))) (if (< (* (- y x) (/ z t)) 0.0) (+ x (/ (* (- y x) z) t)) (+ x (/ (- y x) (/ t z)))))
(+ x (* (- y x) (/ z t))))