Talk:Not a Number - Revision history

Colin-adams at 14:27, 23 February 2010

2010-02-23T14:27:44Z

Peter gummer: /* One possibility for working with NaN */

2010-02-22T14:44:43Z

‎One possibility for working with NaN

Colin-adams at 10:17, 22 February 2010

2010-02-22T10:17:45Z

Saunders: /* One possibility for working with NaN */ new section

2010-02-20T03:18:23Z

‎One possibility for working with NaN: new section

Manus at 17:37, 8 May 2007

2007-05-08T17:37:29Z

New page

'''--[[User:Manus|manus]] 19:37, 8 May 2007 (CEST)''': Have a look at [[Real_numbers| Real Numbers]] page where we already started a similar discussion but currently only for the specification of REAL_64, not its usage.

← Older revision		Revision as of 14:27, 23 February 2010
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	---[[User:Peter gummer\|Peter gummer]] 14:44, 22 February 2010 (UTC): Whoever pasted the code there had formatted it, but without suitable mark-up it came out on one line. I've added the mark-up ... how's that look now?		---[[User:Peter gummer\|Peter gummer]] 14:44, 22 February 2010 (UTC): Whoever pasted the code there had formatted it, but without suitable mark-up it came out on one line. I've added the mark-up ... how's that look now?
		+
		+	--[[User:Colin-adams\|Colin-adams]] 14:27, 23 February 2010 (UTC)So that is pretending that two NaNs compare equal. Which is unsound. you are saying that the complex numbers (0/0, 1) and (0/0, 1) are equal. The whole problem arises because they are not comparable.

@@ Line 5: / Line 5: @@
 I was working on a project to represent complex numbers and used the following `is_equal' to accomodate the use of NaNs:
+<e>
 	is_equal (other: like Current): BOOLEAN
 			-- Is `other' attached to an object considered
@@ Line 24: / Line 24: @@
 			end
 		end
 --[[User:Colin-adams|Colin-adams]] 10:17, 22 February 2010 (UTC) Can you format that code? I can't follow it at all as it stands.

← Older revision		Revision as of 10:17, 22 February 2010
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	end		end
	end		end
		+
		+	--[[User:Colin-adams\|Colin-adams]] 10:17, 22 February 2010 (UTC) Can you format that code? I can't follow it at all as it stands.

← Older revision		Revision as of 03:18, 20 February 2010
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	'''--[[User:Manus\|manus]] 19:37, 8 May 2007 (CEST)''': Have a look at [[Real_numbers\| Real Numbers]] page where we already started a similar discussion but currently only for the specification of REAL_64, not its usage.		'''--[[User:Manus\|manus]] 19:37, 8 May 2007 (CEST)''': Have a look at [[Real_numbers\| Real Numbers]] page where we already started a similar discussion but currently only for the specification of REAL_64, not its usage.
		+
		+	== One possibility for working with NaN ==
		+
		+	I was working on a project to represent complex numbers and used the following `is_equal' to accomodate the use of NaNs:
		+
		+
		+	is_equal (other: like Current): BOOLEAN
		+	-- Is `other' attached to an object considered
		+	-- equal to current object?
		+	-- If current object is not a number (NaN) and
		+	-- `other' is as well `True' will be returned.
		+	do
		+	if is_nan then
		+	if real /~ real and then imaginary ~ imaginary then
		+	Result := real /~ other.real and then imaginary ~ other.imaginary
		+	elseif real ~ real and then imaginary /~ imaginary then
		+	Result := real ~ other.real and then imaginary /~ other.imaginary
		+	elseif real /~ real and then imaginary /~ imaginary then
		+	Result := real /~ other.real and then imaginary /~ other.imaginary
		+	end
		+	else
		+	Result := real ~ other.real and then imaginary ~ other.imaginary
		+	end
		+	end