Commit c5ae0bbd authored by Raymond Toy's avatar Raymond Toy
Browse files

Fix #77: Add tests for sqrt of exceptional values

Add tests for the test cases listed in the bug.  Cmucl currently
passes with no additional changes.
parent d5853cfb
......@@ -172,3 +172,62 @@
(assert-eql 1 (expt -1 (1+ power)))))
(assert-eql 0 (expt 0 power))
(assert-error 'division-by-zero (expt 0 (- power)))))
(define-test sqrt-exceptional-vales
;; Short cuts for +infinity, -infinity, and NaN (where NaN has a
;; positive sign).
(let ((nan (abs (ext:with-float-traps-masked (:invalid :divide-by-zero)
;; This produces some NaN. We don't care what the
;; actual bits are.
(/ 0d0 0d0))))
(inf #.ext:double-float-positive-infinity)
(minf #.ext:double-float-negative-infinity))
;; These tests come from Kahan's paper, Branch Cuts for Elementary
;; Functions.
(ext:with-float-traps-masked (:invalid)
;; sqrt(-beta +/- i0) = +0 +/- sqrt(beta), beta >= 0
(assert-eql (complex +0d0 2d0)
(sqrt (complex -4d0 +0d0)))
(assert-eql (complex +0d0 -2d0)
(sqrt (complex -4d0 -0d0)))
;; sqrt(x +/- inf) = +inf +/- inf for all finite x.
(assert-eql (complex inf inf)
(sqrt (complex 4d0 inf)))
(assert-eql (complex inf minf)
(sqrt (complex 4d0 minf)))
;; sqrt(NaN + i*beta) = NaN + i NaN
(let ((z (sqrt (complex nan 4d0))))
(assert-true (ext:float-nan-p (realpart z)))
(assert-true (ext:float-nan-p (imagpart z))))
;; sqrt(beta +i NaN) = NaN + i NaN
(let ((z (sqrt (complex 4d0 nan))))
(assert-true (ext:float-nan-p (realpart z)))
(assert-true (ext:float-nan-p (imagpart z))))
;; sqrt(NaN + iNaN) = NaN + i NaN
(let ((z (sqrt (complex nan nan))))
(assert-true (ext:float-nan-p (realpart z)))
(assert-true (ext:float-nan-p (imagpart z))))
;; sqrt(inf +/- i beta) = inf +/- i0
(assert-eql (complex inf +0d0)
(sqrt (complex inf 4d0)))
(assert-eql (complex inf -0d0)
(sqrt (complex inf -4d0)))
;; sqrt(inf +/- i NaN) = inf + i NaN
(let ((z (sqrt (complex inf nan))))
(assert-eql inf (realpart z))
(assert-true (ext:float-nan-p (imagpart z))))
(let ((z (sqrt (complex inf (- nan)))))
(assert-eql inf (realpart z))
(assert-true (ext:float-nan-p (imagpart z))))
;; sqrt(-inf +/- i beta) = +0 +/- i*inf
(assert-eql (complex 0d0 inf)
(sqrt (complex minf +4d0)))
(assert-eql (complex 0d0 minf)
(sqrt (complex minf -4d0)))
;; sqrt(-inf +/- i NaN) = NaN +/- i inf
(let ((z (sqrt (complex minf nan))))
(assert-true (ext:float-nan-p (realpart z)))
(assert-eql inf (imagpart z)))
(let ((z (sqrt (complex minf (- nan)))))
(assert-true (ext:float-nan-p (realpart z)))
(assert-eql minf (imagpart z))))))
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