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(math-pow-of-zero): Take into account different cases.

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This commit is contained in:
Jay Belanger 2004-11-29 22:41:10 +00:00
parent 5f9e0ca5da
commit 6adaed7889
1 changed files with 29 additions and 17 deletions
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46
lisp/calc/calc-arith.el
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@ -1740,23 +1740,35 @@
(math-normalize (list '^ a b)))
(defun math-pow-of-zero (a b)
(if (Math-zerop b)
(if calc-infinite-mode
'(var nan var-nan)
(math-reject-arg (list '^ a b) "*Indeterminate form"))
(if (math-floatp b) (setq a (math-float a)))
(if (math-posp b)
a
(if (math-negp b)
(math-div 1 a)
(if (math-infinitep b)
'(var nan var-nan)
(if (and (eq (car b) 'intv) (math-intv-constp b)
calc-infinite-mode)
'(intv 3 (neg (var inf var-inf)) (var inf var-inf))
(if (math-objectp b)
(list '^ a b)
a)))))))
"Raise A to the power of B, where A is a form of zero."
(if (math-floatp b) (setq a (math-float a)))
(cond
;; 0^0 = 1
((eq b 0)
1)
;; 0^0.0, etc., are undetermined
((Math-zerop b)
(if calc-infinite-mode
'(var nan var-nan)
(math-reject-arg (list '^ a b) "*Indeterminate form")))
;; 0^positive = 0
((math-posp b)
a)
;; 0^negative is undefined (let math-div handle it)
((math-negp b)
(math-div 1 a))
;; 0^infinity is undefined
((math-infinitep b)
'(var nan var-nan))
;; Some intervals
((and (eq (car b) 'intv)
calc-infinite-mode
(math-negp (nth 2 b))
(math-posp (nth 3 b)))
'(intv 3 (neg (var inf var-inf)) (var inf var-inf)))
;; If none of the above, leave it alone.
(t
(list '^ a b))))
(defun math-pow-zero (a b)
(if (eq (car-safe a) 'mod)