Exception for bug366, discussion (missed optimization)

Specification

Math

\[\begin{array}{l} \\ \sqrt{a \cdot a - b \cdot b} \end{array} \]

FPCore

(FPCore (a b) :precision binary64 (sqrt (- (* a a) (* b b))))

C

double code(double a, double b) {
	return sqrt(((a * a) - (b * b)));
}

Fortran

real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = sqrt(((a * a) - (b * b)))
end function

Java

public static double code(double a, double b) {
	return Math.sqrt(((a * a) - (b * b)));
}

Python

def code(a, b):
	return math.sqrt(((a * a) - (b * b)))

Julia

function code(a, b)
	return sqrt(Float64(Float64(a * a) - Float64(b * b)))
end

MATLAB

function tmp = code(a, b)
	tmp = sqrt(((a * a) - (b * b)));
end

Wolfram

code[a_, b_] := N[Sqrt[N[(N[(a * a), $MachinePrecision] - N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]

Reproduce

herbie shell --seed 2024005 
(FPCore (a b)
  :name "bug366, discussion (missed optimization)"
  :precision binary64

  :herbie-target
  (* (sqrt (+ (fabs a) (fabs b))) (sqrt (- (fabs a) (fabs b))))

  (sqrt (- (* a a) (* b b))))

Please file a bug report with this information.

Backtrace

repr->cost: arity mismatch; the expected number of arguments does not match the given number expected: 2 given: 1		L	C
loop	.../private/map.rkt	54	19
f490	.../match/compiler.rkt	548	40
loop	.../private/map.rkt	54	19
f490	.../match/compiler.rkt	548	40
loop	.../private/map.rkt	54	19
f490	.../match/compiler.rkt	548	40
make-alt-table	/home/nightlies/herbie/platforms/src/core/alt-table.rkt	40	0
(unnamed)	/usr/share/racket/collects/racket/contract/private/arrow-val-first.rkt	486	18
initialize-alt-table!	/home/nightlies/herbie/platforms/src/mainloop.rkt	316	0
mutate!	/home/nightlies/herbie/platforms/src/mainloop.rkt	352	0
run-improve!	/home/nightlies/herbie/platforms/src/mainloop.rkt	338	0
get-alternatives/report	/home/nightlies/herbie/platforms/src/sandbox.rkt	169	0
(unnamed)	/home/nightlies/herbie/platforms/src/sandbox.rkt	262	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