\[wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}}\]

wj - \frac{wj \cdot e^{wj} - x}{e^{wj} + wj \cdot e^{wj}}

double f(double wj, double x) {
        double r31235 = wj;
        double r31236 = exp(r31235);
        double r31237 = r31235 * r31236;
        double r31238 = x;
        double r31239 = r31237 - r31238;
        double r31240 = r31236 + r31237;
        double r31241 = r31239 / r31240;
        double r31242 = r31235 - r31241;
        return r31242;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019315 
(FPCore (wj x)
  :name "Jmat.Real.lambertw, newton loop step"
  :precision binary64

  :herbie-target
  (- wj (- (/ wj (+ wj 1)) (/ x (+ (exp wj) (* wj (exp wj))))))

  (- wj (/ (- (* wj (exp wj)) x) (+ (exp wj) (* wj (exp wj))))))

Backtrace

match: no matching clause for 'binary64		L	C
match:error	/opt/racket-7.2/collects/racket/match/runtime.rkt	24	0
for-loop	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/reduce.rkt	246	3
make-multiplication-subnode	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/reduce.rkt	244	0
make-multiplication-node	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/reduce.rkt	234	0
map	/opt/racket-7.2/collects/racket/private/map.rkt	35	13
f45	/opt/racket-7.2/collects/racket/match/compiler.rkt	507	40
map	/opt/racket-7.2/collects/racket/private/map.rkt	35	13
f45	/opt/racket-7.2/collects/racket/match/compiler.rkt	507	40
simplify	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/reduce.rkt	16	0
(unnamed)	/opt/racket-7.2/collects/racket/contract/private/arrow-higher-order.rkt	360	33
location-do	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/programs.rkt	64	0
(unnamed)	/opt/racket-7.2/collects/racket/contract/private/arrow-higher-order.rkt	360	33
for-loop	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	151	6
taylor-alt	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	145	0
for-loop	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	166	7
gen-series!	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	159	0
run-iter!	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	326	0
for-loop	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	364	4
run-improve47	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	345	0
(unnamed)	/opt/racket-7.2/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.2/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.2/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.2/collects/racket/private/more-scheme.rkt	261	28

could not determine a ground truth for program body (more)

Reproduce

Backtrace