
(FPCore (re im) :precision binary64 (* (* 0.5 (cos re)) (+ (exp (- im)) (exp im))))
double code(double re, double im) {
return (0.5 * cos(re)) * (exp(-im) + exp(im));
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
code = (0.5d0 * cos(re)) * (exp(-im) + exp(im))
end function
public static double code(double re, double im) {
return (0.5 * Math.cos(re)) * (Math.exp(-im) + Math.exp(im));
}
def code(re, im): return (0.5 * math.cos(re)) * (math.exp(-im) + math.exp(im))
function code(re, im) return Float64(Float64(0.5 * cos(re)) * Float64(exp(Float64(-im)) + exp(im))) end
function tmp = code(re, im) tmp = (0.5 * cos(re)) * (exp(-im) + exp(im)); end
code[re_, im_] := N[(N[(0.5 * N[Cos[re], $MachinePrecision]), $MachinePrecision] * N[(N[Exp[(-im)], $MachinePrecision] + N[Exp[im], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(0.5 \cdot \cos re\right) \cdot \left(e^{-im} + e^{im}\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 11 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (re im) :precision binary64 (* (* 0.5 (cos re)) (+ (exp (- im)) (exp im))))
double code(double re, double im) {
return (0.5 * cos(re)) * (exp(-im) + exp(im));
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
code = (0.5d0 * cos(re)) * (exp(-im) + exp(im))
end function
public static double code(double re, double im) {
return (0.5 * Math.cos(re)) * (Math.exp(-im) + Math.exp(im));
}
def code(re, im): return (0.5 * math.cos(re)) * (math.exp(-im) + math.exp(im))
function code(re, im) return Float64(Float64(0.5 * cos(re)) * Float64(exp(Float64(-im)) + exp(im))) end
function tmp = code(re, im) tmp = (0.5 * cos(re)) * (exp(-im) + exp(im)); end
code[re_, im_] := N[(N[(0.5 * N[Cos[re], $MachinePrecision]), $MachinePrecision] * N[(N[Exp[(-im)], $MachinePrecision] + N[Exp[im], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(0.5 \cdot \cos re\right) \cdot \left(e^{-im} + e^{im}\right)
\end{array}
(FPCore (re im) :precision binary64 (* (* 0.5 (cos re)) (+ (exp (- im)) (exp im))))
double code(double re, double im) {
return (0.5 * cos(re)) * (exp(-im) + exp(im));
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
code = (0.5d0 * cos(re)) * (exp(-im) + exp(im))
end function
public static double code(double re, double im) {
return (0.5 * Math.cos(re)) * (Math.exp(-im) + Math.exp(im));
}
def code(re, im): return (0.5 * math.cos(re)) * (math.exp(-im) + math.exp(im))
function code(re, im) return Float64(Float64(0.5 * cos(re)) * Float64(exp(Float64(-im)) + exp(im))) end
function tmp = code(re, im) tmp = (0.5 * cos(re)) * (exp(-im) + exp(im)); end
code[re_, im_] := N[(N[(0.5 * N[Cos[re], $MachinePrecision]), $MachinePrecision] * N[(N[Exp[(-im)], $MachinePrecision] + N[Exp[im], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(0.5 \cdot \cos re\right) \cdot \left(e^{-im} + e^{im}\right)
\end{array}
Initial program 100.0%
Final simplification100.0%
(FPCore (re im)
:precision binary64
(if (<= im 0.0085)
(cos re)
(if (<= im 1.35e+154)
(* 0.5 (+ (exp (- im)) (exp im)))
(* (cos re) (* 0.5 (pow im 2.0))))))
double code(double re, double im) {
double tmp;
if (im <= 0.0085) {
tmp = cos(re);
} else if (im <= 1.35e+154) {
tmp = 0.5 * (exp(-im) + exp(im));
} else {
tmp = cos(re) * (0.5 * pow(im, 2.0));
}
return tmp;
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
real(8) :: tmp
if (im <= 0.0085d0) then
tmp = cos(re)
else if (im <= 1.35d+154) then
tmp = 0.5d0 * (exp(-im) + exp(im))
else
tmp = cos(re) * (0.5d0 * (im ** 2.0d0))
end if
code = tmp
end function
public static double code(double re, double im) {
double tmp;
if (im <= 0.0085) {
tmp = Math.cos(re);
} else if (im <= 1.35e+154) {
tmp = 0.5 * (Math.exp(-im) + Math.exp(im));
} else {
tmp = Math.cos(re) * (0.5 * Math.pow(im, 2.0));
}
return tmp;
}
def code(re, im): tmp = 0 if im <= 0.0085: tmp = math.cos(re) elif im <= 1.35e+154: tmp = 0.5 * (math.exp(-im) + math.exp(im)) else: tmp = math.cos(re) * (0.5 * math.pow(im, 2.0)) return tmp
function code(re, im) tmp = 0.0 if (im <= 0.0085) tmp = cos(re); elseif (im <= 1.35e+154) tmp = Float64(0.5 * Float64(exp(Float64(-im)) + exp(im))); else tmp = Float64(cos(re) * Float64(0.5 * (im ^ 2.0))); end return tmp end
function tmp_2 = code(re, im) tmp = 0.0; if (im <= 0.0085) tmp = cos(re); elseif (im <= 1.35e+154) tmp = 0.5 * (exp(-im) + exp(im)); else tmp = cos(re) * (0.5 * (im ^ 2.0)); end tmp_2 = tmp; end
code[re_, im_] := If[LessEqual[im, 0.0085], N[Cos[re], $MachinePrecision], If[LessEqual[im, 1.35e+154], N[(0.5 * N[(N[Exp[(-im)], $MachinePrecision] + N[Exp[im], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[re], $MachinePrecision] * N[(0.5 * N[Power[im, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;im \leq 0.0085:\\
\;\;\;\;\cos re\\
\mathbf{elif}\;im \leq 1.35 \cdot 10^{+154}:\\
\;\;\;\;0.5 \cdot \left(e^{-im} + e^{im}\right)\\
\mathbf{else}:\\
\;\;\;\;\cos re \cdot \left(0.5 \cdot {im}^{2}\right)\\
\end{array}
\end{array}
if im < 0.0085000000000000006Initial program 100.0%
Taylor expanded in im around 0 66.9%
if 0.0085000000000000006 < im < 1.35000000000000003e154Initial program 100.0%
Taylor expanded in re around 0 70.5%
if 1.35000000000000003e154 < im Initial program 100.0%
Applied egg-rr100.0%
Taylor expanded in im around 0 100.0%
associate-*r*100.0%
distribute-rgt1-in100.0%
Simplified100.0%
Taylor expanded in im around inf 100.0%
associate-*r*100.0%
*-commutative100.0%
Simplified100.0%
Final simplification72.3%
(FPCore (re im)
:precision binary64
(if (<= im 0.0095)
(* (* 0.5 (cos re)) (+ 2.0 (pow im 2.0)))
(if (<= im 1.35e+154)
(* 0.5 (+ (exp (- im)) (exp im)))
(* (cos re) (* 0.5 (pow im 2.0))))))
double code(double re, double im) {
double tmp;
if (im <= 0.0095) {
tmp = (0.5 * cos(re)) * (2.0 + pow(im, 2.0));
} else if (im <= 1.35e+154) {
tmp = 0.5 * (exp(-im) + exp(im));
} else {
tmp = cos(re) * (0.5 * pow(im, 2.0));
}
return tmp;
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
real(8) :: tmp
if (im <= 0.0095d0) then
tmp = (0.5d0 * cos(re)) * (2.0d0 + (im ** 2.0d0))
else if (im <= 1.35d+154) then
tmp = 0.5d0 * (exp(-im) + exp(im))
else
tmp = cos(re) * (0.5d0 * (im ** 2.0d0))
end if
code = tmp
end function
public static double code(double re, double im) {
double tmp;
if (im <= 0.0095) {
tmp = (0.5 * Math.cos(re)) * (2.0 + Math.pow(im, 2.0));
} else if (im <= 1.35e+154) {
tmp = 0.5 * (Math.exp(-im) + Math.exp(im));
} else {
tmp = Math.cos(re) * (0.5 * Math.pow(im, 2.0));
}
return tmp;
}
def code(re, im): tmp = 0 if im <= 0.0095: tmp = (0.5 * math.cos(re)) * (2.0 + math.pow(im, 2.0)) elif im <= 1.35e+154: tmp = 0.5 * (math.exp(-im) + math.exp(im)) else: tmp = math.cos(re) * (0.5 * math.pow(im, 2.0)) return tmp
function code(re, im) tmp = 0.0 if (im <= 0.0095) tmp = Float64(Float64(0.5 * cos(re)) * Float64(2.0 + (im ^ 2.0))); elseif (im <= 1.35e+154) tmp = Float64(0.5 * Float64(exp(Float64(-im)) + exp(im))); else tmp = Float64(cos(re) * Float64(0.5 * (im ^ 2.0))); end return tmp end
function tmp_2 = code(re, im) tmp = 0.0; if (im <= 0.0095) tmp = (0.5 * cos(re)) * (2.0 + (im ^ 2.0)); elseif (im <= 1.35e+154) tmp = 0.5 * (exp(-im) + exp(im)); else tmp = cos(re) * (0.5 * (im ^ 2.0)); end tmp_2 = tmp; end
code[re_, im_] := If[LessEqual[im, 0.0095], N[(N[(0.5 * N[Cos[re], $MachinePrecision]), $MachinePrecision] * N[(2.0 + N[Power[im, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[im, 1.35e+154], N[(0.5 * N[(N[Exp[(-im)], $MachinePrecision] + N[Exp[im], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[Cos[re], $MachinePrecision] * N[(0.5 * N[Power[im, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;im \leq 0.0095:\\
\;\;\;\;\left(0.5 \cdot \cos re\right) \cdot \left(2 + {im}^{2}\right)\\
\mathbf{elif}\;im \leq 1.35 \cdot 10^{+154}:\\
\;\;\;\;0.5 \cdot \left(e^{-im} + e^{im}\right)\\
\mathbf{else}:\\
\;\;\;\;\cos re \cdot \left(0.5 \cdot {im}^{2}\right)\\
\end{array}
\end{array}
if im < 0.00949999999999999976Initial program 100.0%
Taylor expanded in im around 0 83.3%
if 0.00949999999999999976 < im < 1.35000000000000003e154Initial program 100.0%
Taylor expanded in re around 0 70.5%
if 1.35000000000000003e154 < im Initial program 100.0%
Applied egg-rr100.0%
Taylor expanded in im around 0 100.0%
associate-*r*100.0%
distribute-rgt1-in100.0%
Simplified100.0%
Taylor expanded in im around inf 100.0%
associate-*r*100.0%
*-commutative100.0%
Simplified100.0%
Final simplification84.1%
(FPCore (re im) :precision binary64 (if (<= im 0.009) (cos re) (* 0.5 (+ (exp (- im)) (exp im)))))
double code(double re, double im) {
double tmp;
if (im <= 0.009) {
tmp = cos(re);
} else {
tmp = 0.5 * (exp(-im) + exp(im));
}
return tmp;
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
real(8) :: tmp
if (im <= 0.009d0) then
tmp = cos(re)
else
tmp = 0.5d0 * (exp(-im) + exp(im))
end if
code = tmp
end function
public static double code(double re, double im) {
double tmp;
if (im <= 0.009) {
tmp = Math.cos(re);
} else {
tmp = 0.5 * (Math.exp(-im) + Math.exp(im));
}
return tmp;
}
def code(re, im): tmp = 0 if im <= 0.009: tmp = math.cos(re) else: tmp = 0.5 * (math.exp(-im) + math.exp(im)) return tmp
function code(re, im) tmp = 0.0 if (im <= 0.009) tmp = cos(re); else tmp = Float64(0.5 * Float64(exp(Float64(-im)) + exp(im))); end return tmp end
function tmp_2 = code(re, im) tmp = 0.0; if (im <= 0.009) tmp = cos(re); else tmp = 0.5 * (exp(-im) + exp(im)); end tmp_2 = tmp; end
code[re_, im_] := If[LessEqual[im, 0.009], N[Cos[re], $MachinePrecision], N[(0.5 * N[(N[Exp[(-im)], $MachinePrecision] + N[Exp[im], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;im \leq 0.009:\\
\;\;\;\;\cos re\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \left(e^{-im} + e^{im}\right)\\
\end{array}
\end{array}
if im < 0.00899999999999999932Initial program 100.0%
Taylor expanded in im around 0 66.9%
if 0.00899999999999999932 < im Initial program 100.0%
Taylor expanded in re around 0 70.8%
Final simplification68.0%
(FPCore (re im)
:precision binary64
(if (<= im 4.1e+19)
(cos re)
(if (<= im 1.05e+144)
(+ 0.25 (* 0.25 (pow re 2.0)))
(* 0.5 (fma im im 2.0)))))
double code(double re, double im) {
double tmp;
if (im <= 4.1e+19) {
tmp = cos(re);
} else if (im <= 1.05e+144) {
tmp = 0.25 + (0.25 * pow(re, 2.0));
} else {
tmp = 0.5 * fma(im, im, 2.0);
}
return tmp;
}
function code(re, im) tmp = 0.0 if (im <= 4.1e+19) tmp = cos(re); elseif (im <= 1.05e+144) tmp = Float64(0.25 + Float64(0.25 * (re ^ 2.0))); else tmp = Float64(0.5 * fma(im, im, 2.0)); end return tmp end
code[re_, im_] := If[LessEqual[im, 4.1e+19], N[Cos[re], $MachinePrecision], If[LessEqual[im, 1.05e+144], N[(0.25 + N[(0.25 * N[Power[re, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(0.5 * N[(im * im + 2.0), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;im \leq 4.1 \cdot 10^{+19}:\\
\;\;\;\;\cos re\\
\mathbf{elif}\;im \leq 1.05 \cdot 10^{+144}:\\
\;\;\;\;0.25 + 0.25 \cdot {re}^{2}\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \mathsf{fma}\left(im, im, 2\right)\\
\end{array}
\end{array}
if im < 4.1e19Initial program 100.0%
Taylor expanded in im around 0 65.4%
if 4.1e19 < im < 1.04999999999999998e144Initial program 100.0%
Applied egg-rr2.4%
Taylor expanded in re around 0 19.9%
*-commutative19.9%
Simplified19.9%
if 1.04999999999999998e144 < im Initial program 100.0%
Taylor expanded in re around 0 71.8%
Taylor expanded in im around 0 69.6%
+-commutative69.6%
unpow269.6%
fma-def69.6%
Simplified69.6%
Final simplification61.1%
(FPCore (re im) :precision binary64 (if (<= im 4.7e+32) (cos re) (* 0.5 (+ 2.0 (* 0.002777777777777778 (pow im 6.0))))))
double code(double re, double im) {
double tmp;
if (im <= 4.7e+32) {
tmp = cos(re);
} else {
tmp = 0.5 * (2.0 + (0.002777777777777778 * pow(im, 6.0)));
}
return tmp;
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
real(8) :: tmp
if (im <= 4.7d+32) then
tmp = cos(re)
else
tmp = 0.5d0 * (2.0d0 + (0.002777777777777778d0 * (im ** 6.0d0)))
end if
code = tmp
end function
public static double code(double re, double im) {
double tmp;
if (im <= 4.7e+32) {
tmp = Math.cos(re);
} else {
tmp = 0.5 * (2.0 + (0.002777777777777778 * Math.pow(im, 6.0)));
}
return tmp;
}
def code(re, im): tmp = 0 if im <= 4.7e+32: tmp = math.cos(re) else: tmp = 0.5 * (2.0 + (0.002777777777777778 * math.pow(im, 6.0))) return tmp
function code(re, im) tmp = 0.0 if (im <= 4.7e+32) tmp = cos(re); else tmp = Float64(0.5 * Float64(2.0 + Float64(0.002777777777777778 * (im ^ 6.0)))); end return tmp end
function tmp_2 = code(re, im) tmp = 0.0; if (im <= 4.7e+32) tmp = cos(re); else tmp = 0.5 * (2.0 + (0.002777777777777778 * (im ^ 6.0))); end tmp_2 = tmp; end
code[re_, im_] := If[LessEqual[im, 4.7e+32], N[Cos[re], $MachinePrecision], N[(0.5 * N[(2.0 + N[(0.002777777777777778 * N[Power[im, 6.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;im \leq 4.7 \cdot 10^{+32}:\\
\;\;\;\;\cos re\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \left(2 + 0.002777777777777778 \cdot {im}^{6}\right)\\
\end{array}
\end{array}
if im < 4.70000000000000023e32Initial program 100.0%
Taylor expanded in im around 0 64.2%
if 4.70000000000000023e32 < im Initial program 100.0%
Taylor expanded in re around 0 73.0%
Taylor expanded in im around 0 68.6%
Taylor expanded in im around inf 68.6%
Final simplification65.2%
(FPCore (re im) :precision binary64 (if (<= im 0.0095) (cos re) (* 0.5 (fma im im 2.0))))
double code(double re, double im) {
double tmp;
if (im <= 0.0095) {
tmp = cos(re);
} else {
tmp = 0.5 * fma(im, im, 2.0);
}
return tmp;
}
function code(re, im) tmp = 0.0 if (im <= 0.0095) tmp = cos(re); else tmp = Float64(0.5 * fma(im, im, 2.0)); end return tmp end
code[re_, im_] := If[LessEqual[im, 0.0095], N[Cos[re], $MachinePrecision], N[(0.5 * N[(im * im + 2.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;im \leq 0.0095:\\
\;\;\;\;\cos re\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \mathsf{fma}\left(im, im, 2\right)\\
\end{array}
\end{array}
if im < 0.00949999999999999976Initial program 100.0%
Taylor expanded in im around 0 66.9%
if 0.00949999999999999976 < im Initial program 100.0%
Taylor expanded in re around 0 70.8%
Taylor expanded in im around 0 40.3%
+-commutative40.3%
unpow240.3%
fma-def40.3%
Simplified40.3%
Final simplification59.4%
(FPCore (re im) :precision binary64 (if (<= im 6e+83) (cos re) (* 0.5 (pow im 2.0))))
double code(double re, double im) {
double tmp;
if (im <= 6e+83) {
tmp = cos(re);
} else {
tmp = 0.5 * pow(im, 2.0);
}
return tmp;
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
real(8) :: tmp
if (im <= 6d+83) then
tmp = cos(re)
else
tmp = 0.5d0 * (im ** 2.0d0)
end if
code = tmp
end function
public static double code(double re, double im) {
double tmp;
if (im <= 6e+83) {
tmp = Math.cos(re);
} else {
tmp = 0.5 * Math.pow(im, 2.0);
}
return tmp;
}
def code(re, im): tmp = 0 if im <= 6e+83: tmp = math.cos(re) else: tmp = 0.5 * math.pow(im, 2.0) return tmp
function code(re, im) tmp = 0.0 if (im <= 6e+83) tmp = cos(re); else tmp = Float64(0.5 * (im ^ 2.0)); end return tmp end
function tmp_2 = code(re, im) tmp = 0.0; if (im <= 6e+83) tmp = cos(re); else tmp = 0.5 * (im ^ 2.0); end tmp_2 = tmp; end
code[re_, im_] := If[LessEqual[im, 6e+83], N[Cos[re], $MachinePrecision], N[(0.5 * N[Power[im, 2.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;im \leq 6 \cdot 10^{+83}:\\
\;\;\;\;\cos re\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot {im}^{2}\\
\end{array}
\end{array}
if im < 5.9999999999999999e83Initial program 100.0%
Taylor expanded in im around 0 61.4%
if 5.9999999999999999e83 < im Initial program 100.0%
Applied egg-rr100.0%
Taylor expanded in im around 0 72.4%
associate-*r*72.4%
distribute-rgt1-in72.4%
Simplified72.4%
Taylor expanded in im around inf 72.4%
associate-*r*72.4%
*-commutative72.4%
Simplified72.4%
Taylor expanded in re around 0 51.7%
*-commutative51.7%
Simplified51.7%
Final simplification59.4%
(FPCore (re im) :precision binary64 (cos re))
double code(double re, double im) {
return cos(re);
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
code = cos(re)
end function
public static double code(double re, double im) {
return Math.cos(re);
}
def code(re, im): return math.cos(re)
function code(re, im) return cos(re) end
function tmp = code(re, im) tmp = cos(re); end
code[re_, im_] := N[Cos[re], $MachinePrecision]
\begin{array}{l}
\\
\cos re
\end{array}
Initial program 100.0%
Taylor expanded in im around 0 49.1%
Final simplification49.1%
(FPCore (re im) :precision binary64 0.25)
double code(double re, double im) {
return 0.25;
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
code = 0.25d0
end function
public static double code(double re, double im) {
return 0.25;
}
def code(re, im): return 0.25
function code(re, im) return 0.25 end
function tmp = code(re, im) tmp = 0.25; end
code[re_, im_] := 0.25
\begin{array}{l}
\\
0.25
\end{array}
Initial program 100.0%
Applied egg-rr7.5%
Taylor expanded in re around 0 7.7%
Final simplification7.7%
(FPCore (re im) :precision binary64 1.0)
double code(double re, double im) {
return 1.0;
}
real(8) function code(re, im)
real(8), intent (in) :: re
real(8), intent (in) :: im
code = 1.0d0
end function
public static double code(double re, double im) {
return 1.0;
}
def code(re, im): return 1.0
function code(re, im) return 1.0 end
function tmp = code(re, im) tmp = 1.0; end
code[re_, im_] := 1.0
\begin{array}{l}
\\
1
\end{array}
Initial program 100.0%
Taylor expanded in im around 0 49.1%
Taylor expanded in re around 0 24.6%
Final simplification24.6%
herbie shell --seed 2024010
(FPCore (re im)
:name "math.cos on complex, real part"
:precision binary64
(* (* 0.5 (cos re)) (+ (exp (- im)) (exp im))))