\[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]

\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)

double f(double a, double b) {
        double r17330 = atan2(1.0, 0.0);
        double r17331 = 2.0;
        double r17332 = r17330 / r17331;
        double r17333 = 1.0;
        double r17334 = b;
        double r17335 = r17334 * r17334;
        double r17336 = a;
        double r17337 = r17336 * r17336;
        double r17338 = r17335 - r17337;
        double r17339 = r17333 / r17338;
        double r17340 = r17332 * r17339;
        double r17341 = r17333 / r17336;
        double r17342 = r17333 / r17334;
        double r17343 = r17341 - r17342;
        double r17344 = r17340 * r17343;
        return r17344;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019194 
(FPCore (a b)
  :name "NMSE Section 6.1 mentioned, B"
  (* (* (/ PI 2.0) (/ 1.0 (- (* b b) (* a a)))) (- (/ 1.0 a) (/ 1.0 b))))

Backtrace

get-representation: Unknown representation #f		L	C
(unnamed)	/data/pavpan/nightlies/herbie/js-tweaks/src/core/localize.rkt	23	13
hash-ref!	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	376	2
map	/opt/racket-7.0/collects/racket/private/map.rkt	35	13
parse-loop30	/opt/racket-7.0/collects/racket/match/compiler.rkt	418	15
hash-ref!	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	376	2
map	/opt/racket-7.0/collects/racket/private/map.rkt	35	13
parse-loop30	/opt/racket-7.0/collects/racket/match/compiler.rkt	418	15
hash-ref!	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	376	2
localize-error	/data/pavpan/nightlies/herbie/js-tweaks/src/core/localize.rkt	61	0
localize!	/data/pavpan/nightlies/herbie/js-tweaks/src/mainloop.rkt	123	0
run-iter!	/data/pavpan/nightlies/herbie/js-tweaks/src/mainloop.rkt	323	0
for-loop	/data/pavpan/nightlies/herbie/js-tweaks/src/mainloop.rkt	359	4
run-improve47	/data/pavpan/nightlies/herbie/js-tweaks/src/mainloop.rkt	342	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28