[Maxima-bugs] [ maxima-Bugs-798571 ] sign(sqrt(2)/2 - 1/sqrt(2)) -> zero, pos, neg, or pnz

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Bugs item #798571, was opened at 2003-09-01 09:10
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Barton Willis (willisb)
Assigned to: Nobody/Anonymous (nobody)
Summary: sign(sqrt(2)/2 - 1/sqrt(2)) -> zero, pos, neg, or pnz

Initial Comment:
Depending on the values of fpprec and signbfloat, 

sign(sqrt(2)/2 - 1/sqrt(2)) evaluates to zero, pos, 

neg, or pnz.



(C1) display2d : false;



(D1) FALSE

(C2)  a : sqrt(2)/2 - 1/sqrt(2);



(D2) SQRT(2)/2-1/SQRT(2)

(C3)  for k : 20 thru 25 do (fpprec : k, print(k,sign(a)));



20 ZERO 

21 POS 

22 ZERO 

23 POS 

24 ZERO 

25 NEG 

(D3) DONE

(C4) sign(a), signbfloat : true;



(D4) NEG

(C5) sign(a), signbfloat : false;



(D5) PNZ



Here is another example -- this time sign(p) should 

evaluate to pos.



(C7) p : exp(x) - sum(x^k/k!,k,0,15)$



(C8) p : subst(1/10000001,x,p)$



(C9) sign(p),signbfloat : true;



(D9) ZERO

(C10) sign(p),signbfloat : false;



(D10) PNZ

(C11) for k : 20 thru 25 do (fpprec : k, print(k,sign

(p)));



20 POS 

21 NEG 

22 NEG 

23 ZERO 

24 POS 

25 ZERO 

(D11) DONE

(C12) 



Additionally, signbfloat isn't documented



(C17) describe("signbfloat");



(D17) FALSE



Barton



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