Exception for 2-ancestry mixing, negative discriminant

Math

\[2 \cdot \cos \left(\frac{2 \cdot \pi}{3} + \frac{\cos^{-1} \left(\frac{-g}{h}\right)}{3}\right) \]

FPCore

(FPCore (g h)
 :precision binary64
 (* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))

C

double code(double g, double h) {
	return 2.0 * cos((((2.0 * ((double) M_PI)) / 3.0) + (acos((-g / h)) / 3.0)));
}

Java

public static double code(double g, double h) {
	return 2.0 * Math.cos((((2.0 * Math.PI) / 3.0) + (Math.acos((-g / h)) / 3.0)));
}

Python

def code(g, h):
	return 2.0 * math.cos((((2.0 * math.pi) / 3.0) + (math.acos((-g / h)) / 3.0)))

Julia

function code(g, h)
	return Float64(2.0 * cos(Float64(Float64(Float64(2.0 * pi) / 3.0) + Float64(acos(Float64(Float64(-g) / h)) / 3.0))))
end

MATLAB

function tmp = code(g, h)
	tmp = 2.0 * cos((((2.0 * pi) / 3.0) + (acos((-g / h)) / 3.0)));
end

Wolfram

code[g_, h_] := N[(2.0 * N[Cos[N[(N[(N[(2.0 * Pi), $MachinePrecision] / 3.0), $MachinePrecision] + N[(N[ArcCos[N[((-g) / h), $MachinePrecision]], $MachinePrecision] / 3.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2022193 
(FPCore (g h)
  :name "2-ancestry mixing, negative discriminant"
  :precision binary64
  (* 2.0 (cos (+ (/ (* 2.0 PI) 3.0) (/ (acos (/ (- g) h)) 3.0)))))

Backtrace

hash-ref: no value found for key key: '~		L	C
(unnamed)	/data/pavpan/nightlies/herbie/ruler-arith/src/syntax/syntax.rkt	202	2
f337	.../match/compiler.rkt	548	40
f337	.../match/compiler.rkt	548	40
expand-parametric	/data/pavpan/nightlies/herbie/ruler-arith/src/syntax/sugar.rkt	62	0
(unnamed)	/data/pavpan/nightlies/herbie/ruler-arith/src/syntax/rules.rkt	175	8
generate-rules-for	/data/pavpan/nightlies/herbie/ruler-arith/src/syntax/rules.rkt	160	0
generate-missing-rules	/data/pavpan/nightlies/herbie/ruler-arith/src/syntax/rules.rkt	186	0
(unnamed)	/data/pavpan/nightlies/herbie/ruler-arith/src/syntax/rules.rkt	30	26
get-swaps	/data/pavpan/nightlies/herbie/ruler-arith/src/symmetry.rkt	6	0
connected-components	/data/pavpan/nightlies/herbie/ruler-arith/src/symmetry.rkt	17	0
run-improve!	/data/pavpan/nightlies/herbie/ruler-arith/src/mainloop.rkt	317	0
(unnamed)	/data/pavpan/nightlies/herbie/ruler-arith/src/sandbox.rkt	56	6
(unnamed)	/usr/share/racket/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/share/racket/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/share/racket/collects/racket/engine.rkt	42	24