Exception for Kahan's exp quotient

• Could not converge on a ground truth

  1. reg0 = (bf "-1.148304914370584353157842719309927537009e-269")

• 25.2% of points produce a very large (infinite) output. You may want to add a precondition.

Specification

Math

\[\begin{array}{l} \\ \frac{e^{x} - 1}{x} \end{array} \]

FPCore

(FPCore (x) :precision binary64 (/ (- (exp x) 1.0) x))

C

double code(double x) {
	return (exp(x) - 1.0) / x;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    code = (exp(x) - 1.0d0) / x
end function

Java

public static double code(double x) {
	return (Math.exp(x) - 1.0) / x;
}

Python

def code(x):
	return (math.exp(x) - 1.0) / x

Julia

function code(x)
	return Float64(Float64(exp(x) - 1.0) / x)
end

MATLAB

function tmp = code(x)
	tmp = (exp(x) - 1.0) / x;
end

Wolfram

code[x_] := N[(N[(N[Exp[x], $MachinePrecision] - 1.0), $MachinePrecision] / x), $MachinePrecision]

Reproduce

herbie shell --seed 2024146 
(FPCore (x)
  :name "Kahan's exp quotient"
  :precision binary64

  :alt
  (! :herbie-platform default (if (and (< x 1) (> x -1)) (/ (- (exp x) 1) (log (exp x))) (/ (- (exp x) 1) x)))

  (/ (- (exp x) 1.0) x))

Please file a bug report with this information.

Backtrace

application: not a procedure; expected a procedure that can be applied to arguments given: #f		L	C
backward-pass	/home/nightlies/herbie/jackson-mergable-platform-changes/src/correct-round.rkt	146	0
compiled-spec	/home/nightlies/herbie/jackson-mergable-platform-changes/src/correct-round.rkt	27	2
compiled-spec	/home/nightlies/herbie/jackson-mergable-platform-changes/src/correct-round.rkt	143	2
compiled-spec	/home/nightlies/herbie/jackson-mergable-platform-changes/src/correct-round.rkt	27	2
compiled-spec	/home/nightlies/herbie/jackson-mergable-platform-changes/src/ground-truth.rkt	31	2
ival-eval	/home/nightlies/herbie/jackson-mergable-platform-changes/src/ground-truth.rkt	55	0
<eval-prog-real>	/home/nightlies/herbie/jackson-mergable-platform-changes/src/ground-truth.rkt	86	2
compute-local-errors	/home/nightlies/herbie/jackson-mergable-platform-changes/src/core/localize.rkt	75	0
batch-localize-errors	/home/nightlies/herbie/jackson-mergable-platform-changes/src/core/localize.rkt	61	0
localize!	/home/nightlies/herbie/jackson-mergable-platform-changes/src/mainloop.rkt	201	0
run-iter!	/home/nightlies/herbie/jackson-mergable-platform-changes/src/mainloop.rkt	73	0
mutate!	/home/nightlies/herbie/jackson-mergable-platform-changes/src/mainloop.rkt	65	0
run-improve!	/home/nightlies/herbie/jackson-mergable-platform-changes/src/mainloop.rkt	51	0
get-alternatives/report	/home/nightlies/herbie/jackson-mergable-platform-changes/src/sandbox.rkt	169	0
(unnamed)	/home/nightlies/herbie/jackson-mergable-platform-changes/src/sandbox.rkt	263	6
(unnamed)	/usr/local/racket/share/pkgs/profile-lib/main.rkt	40	10
profile-thunk	/usr/local/racket/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/usr/local/racket/collects/racket/engine.rkt	42	24