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John,
Currently if you have code buried deep in the system test
you also have the problem when you use 1/0.
In the future I will provide a special "debug" mode that will
print out such warning messages to a seprate window.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "John" <jr-sw@xxxxxxxxxxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Tuesday, March 04, 2003 12:32 PM
Subject: Re: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or Infinity would be good
> Tomasz,
>
> But... (yet another but!) relying on seeing spikes means you must to plot
> the code and then scroll sideways to locate. What about all the code buried
> deep in system tests which is never plotted?
>
> John
> ----- Original Message -----
> From: "Tomasz Janeczko" <amibroker@xxxxxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Tuesday, March 04, 2003 11:15 AM
> Subject: Re: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or Infinity would be
> good
>
>
> > John,
> >
> > It won't get unnoticed simply because plotting 1/0 will give you huge
> > spikes.
> >
> > Best regards,
> > Tomasz Janeczko
> > amibroker.com
> > ----- Original Message -----
> > From: "John" <jr-sw@xxxxxxxxxxxxxxxxx>
> > To: <amibroker@xxxxxxxxxxxxxxx>
> > Sent: Tuesday, March 04, 2003 10:37 AM
> > Subject: Re: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or Infinity would
> be good
> >
> >
> > > Tomasz,
> > >
> > > The proposed functions sound good and would be far more convenient than
> > > IIFs.
> > >
> > > But....(why is there always a but?).. if I forget to use the appropriate
> > > function in my code (i.e. I do not *anticipate* the condition) then will
> the
> > > AFL engine display a Divide by Zero error message when I attempt to plot
> or
> > > use the code? If it does not then my concern is the condition will go
> > > undetected. IMO AFL engine should display message identifying the errror
> and
> > > bar - the user can then take appropriate action - either adding one of
> the
> > > proposed new functions to code or correcting the basic logic error in
> code.
> > >
> > > Sorry to go on about this but I just don't like the idea of "errors"
> going
> > > unreported.
> > >
> > > John
> > >
> > > ----- Original Message -----
> > > From: "Tomasz Janeczko" <amibroker@xxxxxx>
> > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > Sent: Tuesday, March 04, 2003 8:42 AM
> > > Subject: Re: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or Infinity would
> be
> > > good
> > >
> > >
> > > > John,
> > > >
> > > > In the case you mentioned a very high value (+infinite) will be
> plotted.
> > > >
> > > >
> > > > I was thinking about adding function like
> > > >
> > > > IsNan( array/number ) - detects NaN or
> > > > IsFinite( array/number ) - detects if the number is finite (not Nan
> nor
> > > infinite)
> > > >
> > > > Best regards,
> > > > Tomasz Janeczko
> > > > amibroker.com
> > > > ----- Original Message -----
> > > > From: "John" <jr-sw@xxxxxxxxxxxxxxxxx>
> > > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > > Sent: Tuesday, March 04, 2003 1:27 AM
> > > > Subject: Re: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or Infinity
> would
> > > be good
> > > >
> > > >
> > > > > Tomasz or anyone else,
> > > > >
> > > > > Sorry but I am still clear how the proposed handling of Divide by
> Zero
> > > > > errors is going to work.
> > > > >
> > > > > What happens if for example we write some AFL custom indicator code
> > > like:-
> > > > >
> > > > > x=(H-L)/(C-L);
> > > > >
> > > > > When the Close is very near but not equal to the Low indicator plot
> > > value
> > > > > will be big. But when the Close matches the Low exactly the
> indicator
> > > plot
> > > > > value drops to Zero? I know this is the current AFL behaviour
> becuase I
> > > have
> > > > > been caught out by it before ;-)
> > > > >
> > > > > For the indicator to follow a logical progression IMO it should plot
> a
> > > > > bigger value when C-L is zero. So how will this be handled?
> Obviously
> > > one
> > > > > can write code to defend against anticipated zero divides (my
> Metastock
> > > > > indicators are full of these <g>) but without some error message
> from
> > > the
> > > > > AFL engine it seems to me un-anticipated zero divides will get by
> > > > > un-noticed.
> > > > >
> > > > > I am probably missing something here - it's late!
> > > > >
> > > > > John
> > > > >
> > > > > ----- Original Message -----
> > > > > From: "Tomasz Janeczko" <amibroker@xxxxxx>
> > > > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > > > Sent: Monday, March 03, 2003 6:41 PM
> > > > > Subject: Re: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or Infinity
> would
> > > be
> > > > > good
> > > > >
> > > > >
> > > > > > John,
> > > > > >
> > > > > > I don't think so.
> > > > > >
> > > > > > 1/0 will still be displayed as {NaN}
> > > > > >
> > > > > > But statement like this
> > > > > >
> > > > > > 100 / ( 1/ 0 )
> > > > > >
> > > > > > will give zero, which is correct considering the fact
> > > > > > that it could be rewritten to:
> > > > > >
> > > > > > 0 * 100/1
> > > > > >
> > > > > > Best regards,
> > > > > > Tomasz Janeczko
> > > > > > amibroker.com
> > > > > > ----- Original Message -----
> > > > > > From: "John" <jr-sw@xxxxxxxxxxxxxxxxx>
> > > > > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > > > > Sent: Monday, March 03, 2003 7:17 PM
> > > > > > Subject: Re: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or Infinity
> > > would
> > > > > be good
> > > > > >
> > > > > >
> > > > > > > Tomasz,
> > > > > > >
> > > > > > > If you take an automatic approach in AFL engine to Divide by
> Zero
> > > errors
> > > > > > > then won't any genuine user logic/coding errors get masked?
> > > > > > >
> > > > > > > John
> > > > > > > ----- Original Message -----
> > > > > > > From: "Tomasz Janeczko" <amibroker@xxxxxx>
> > > > > > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > > > > > Sent: Monday, March 03, 2003 5:26 PM
> > > > > > > Subject: Re: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or
> Infinity
> > > would
> > > > > be
> > > > > > > good
> > > > > > >
> > > > > > >
> > > > > > > > Mike,
> > > > > > > >
> > > > > > > > A next beta (4.29.8) will give you 100.
> > > > > > > >
> > > > > > > > Best regards,
> > > > > > > > Tomasz Janeczko
> > > > > > > > amibroker.com
> > > > > > > > ----- Original Message -----
> > > > > > > > From: <mik-u@xxxxxxxxxxx>
> > > > > > > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > > > > > > Sent: Monday, March 03, 2003 6:20 PM
> > > > > > > > Subject: [amibroker] Re: [Tomasz] 1 / 0 = 0? : NaN or Infinity
> > > would
> > > > > be
> > > > > > > good
> > > > > > > >
> > > > > > > >
> > > > > > > > > Hi Tomasz,
> > > > > > > > >
> > > > > > > > > NaN or Infinity would be good. I just need something to
> check an
> > > > > > > > > exception and get correct value (100) when calculating
> formula
> > > like
> > > > > > > > > this:
> > > > > > > > >
> > > > > > > > > 100 - 100 / (1 + 30 / 0)
> > > > > > > > >
> > > > > > > > > Regards,
> > > > > > > > > Mike
> > > > > > > > >
> > > > > > > > > --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko"
> > > <amibroker@xxxx>
> > > > > > > > > wrote:
> > > > > > > > > > Hello,
> > > > > > > > > >
> > > > > > > > > > When I am thinking more on this... maybe it would be
> better
> > > > > > > > > > to display a special string "NaN" in such case?
> > > > > > > > > >
> > > > > > > > > > I will modify the WriteVal and this division handling so
> > > > > > > > > > it displays NaN string so it is more obvious what happens.
> > > > > > > > > >
> > > > > > > > > > Best regards,
> > > > > > > > > > Tomasz Janeczko
> > > > > > > > > > amibroker.com
> > > > > > > > > > ----- Original Message -----
> > > > > > > > > > From: "Tomasz Janeczko" <amibroker@xxxx>
> > > > > > > > > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > > > > > > > > Sent: Monday, March 03, 2003 8:57 AM
> > > > > > > > > > Subject: Re: [amibroker] [Tomasz] 1 / 0 = 0?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > > Hello,
> > > > > > > > > > >
> > > > > > > > > > > (30/0) is NaN - NOT a NUMBER
> > > > > > > > > > >
> > > > > > > > > > > Division by zero is illegal operation.
> > > > > > > > > > >
> > > > > > > > > > > If there was no protection against dividing by zero
> > > > > > > > > > > the program would just bomb out (crash and say good
> bye).
> > > > > > > > > > >
> > > > > > > > > > > Therefore when dividing two numbers X / Y AB checks
> > > > > > > > > > > if Y is equal to zero and always returns zero in that
> case.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Best regards,
> > > > > > > > > > > Tomasz Janeczko
> > > > > > > > > > > amibroker.com
> > > > > > > > > > > ----- Original Message -----
> > > > > > > > > > > From: <mik-u@xxxx>
> > > > > > > > > > > To: <amibroker@xxxxxxxxxxxxxxx>
> > > > > > > > > > > Sent: Monday, March 03, 2003 4:00 AM
> > > > > > > > > > > Subject: [amibroker] [Tomasz] 1 / 0 = 0?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > > Tomasz,
> > > > > > > > > > > >
> > > > > > > > > > > > AB returning 0 for an expression like 1 / 0. Is it
> > > correct?
> > > > > > > > > > > >
> > > > > > > > > > > > The following expression
> > > > > > > > > > > >
> > > > > > > > > > > > 100 - 100 / (1 + 30 / 0)
> > > > > > > > > > > >
> > > > > > > > > > > > is equal 0 in AB, but I think it should be equal 100.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Mike
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
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