\[\left(0 < cosTheta \land cosTheta < 0.9999\right) \land \left(-1 < c \land c < 1\right)\]

\[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]

(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (*
    (* (/ 1.0 (sqrt PI)) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))
    (exp (* (- cosTheta) cosTheta))))))

float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + (((1.0f / sqrtf(((float) M_PI))) * (sqrtf(((1.0f - cosTheta) - cosTheta)) / cosTheta)) * expf((-cosTheta * cosTheta))));
}

function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(1.0) / sqrt(Float32(pi))) * Float32(sqrt(Float32(Float32(Float32(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp(Float32(Float32(-cosTheta) * cosTheta)))))
end

function tmp = code(cosTheta, c)
	tmp = single(1.0) / ((single(1.0) + c) + (((single(1.0) / sqrt(single(pi))) * (sqrt(((single(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp((-cosTheta * cosTheta))));
end

\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2022150 
(FPCore (cosTheta c)
  :name "Beckmann Sample, normalization factor"
  :precision binary32
  :pre (and (and (< 0.0 cosTheta) (< cosTheta 0.9999)) (and (< -1.0 c) (< c 1.0)))
  (/ 1.0 (+ (+ 1.0 c) (* (* (/ 1.0 (sqrt PI)) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta)) (exp (* (- cosTheta) cosTheta))))))

Backtrace

application: required keyword argument not supplied procedure: batch-egg-rewrite required keyword: #:rules arguments...: '(#<rule erfc-erf_binary32> #<rule erf-erfc_binary32> #<rule erf-odd_binary32> #<rule prod-diff_binary32> #<rule hypot-udef_binary32> #<rule expm1-log1p-u_binary32> #<rule log1p-expm1-u_binary32> #<rule log1p-udef_binary32> #<rule expm1-udef_binary32> #... #:depths '(1 1 1 1) #:roots '((2) (2) (2) (2))		L	C
(unnamed)	/opt/racket-8.1/collects/racket/private/kw.rkt	1558	14
rewrite-expressions	/data/pavpan/nightlies/herbie/timeline/src/core/matcher.rkt	171	0
gen-rewrites!	/data/pavpan/nightlies/herbie/timeline/src/patch.rkt	144	0
patch-table-run	/data/pavpan/nightlies/herbie/timeline/src/patch.rkt	291	0
(unnamed)	/opt/racket-8.1/collects/racket/contract/private/arrow-val-first.rkt	486	18
run-iter!	/data/pavpan/nightlies/herbie/timeline/src/mainloop.rkt	246	0
mutate!	/data/pavpan/nightlies/herbie/timeline/src/mainloop.rkt	379	0
run-improve!	/data/pavpan/nightlies/herbie/timeline/src/mainloop.rkt	326	0
(unnamed)	/data/pavpan/nightlies/herbie/timeline/src/sandbox.rkt	66	6
(unnamed)	/opt/racket-8.1/share/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/opt/racket-8.1/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-8.1/collects/racket/engine.rkt	42	24