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Re: [EquisMetaStock Group] Re:Creating a Date function



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Gordon

I prefer to solve my own problems with MS so I'll see if I can follow
through on the bad results still evident. If you're using 7.2 it's not going
to be fixed no matter how many people complain.

Roy

> Running your revised code on EOD data for Jan 30th, 2003 the revisions
> have certainly helped so far as the correct year is concerned so thanks
> for that. But as Richard Dale kindly reinforced on your thoughts, the
> inherent engine within Metastock seems flawed using single (32 bit)
> precision  and presumably why it still gives the wrong day and/or month
> sometimes. I tried adding the following filter:
>
> Mov(C*V,65,S) > 60000 AND Sum(If(V=0,1,0),65) < 1
>
> and I was loading and applying 600 days data. Apart from removing a few
> stocks, the filter did not affect the accuracy of the date. I will ask
> Equis the question to see if there is an official work-around (the more
> people that point out such niggles with the program the more chance of
> action in a future updated version - maybe!). FYI, I enclose my gif file
> for my current exploration results.
>
> If I get any positive feedback from Equis I will keep the Group
> informed. In the meantime, thank you and other contributors for your
> assistance and time.
>
> Good hunting -------------->
>
> Regards,
>
> Gordon Sutherland
>
> -----Original Message-----
> From: gosuth@xxxxxxxxxxxx [mailto:gosuth@xxxxxxxxxxxx]
> Sent: Thursday, 30 January 2003 8:05 p.m.
> To: equismetastock@xxxxxxxxxxxxxxx
> Subject: RE: [EquisMetaStock Group] Re:Creating a Date function
>
>
> Thanks Roy for the clarifications and tweaked code, I will check out
> your "antidote" tomorrow morning. Appreciate you assistance.
>
> Regards,
>
> Gordon Sutherland
>
> -----Original Message-----
> From: Roy Larsen [mailto:rlarsen@xxxxxxxxxxxxxx]
> Sent: Thursday, 30 January 2003 7:58 p.m.
> To: equismetastock@xxxxxxxxxxxxxxx
> Subject: Re: [EquisMetaStock Group] Re:Creating a Date function
>
>
> Hi Gordon
>
> > Thanks to you both for responding to my request for help on creating a
> > Date for an expression in the Explorer.
> > This certainly gets me along the right path - thank you - but from the
> > Gif file attached you will see that when I ran an Explorer for your
> > joint responses I get the correct date sometimes (within the last 65
> > days) and sometimes a date which is outside the 65 days and indeed
> > sometimes into 2004! The Date Column on the attached gif is from Roy's
> > code and the Month and Day are from Joe J.'s - they both agree thank
> > goodness!
>
> There are at least two causes for your problem, and there may be others
> that
> I haven't thought of.
>
> I think the first and biggest problem relates to the method MS uses to
> store
> numbers. When the day is multiplied by 1,000,000 we are just asking for
> trouble. I think what is happening (I can't prove but I'm sure I'm
> right) is
> that the addition process is introducing some fraction which is getting
> rounded up to create a year that is 1 higher than it should be. This
> accounts for the 2004 for some issues, and some will no doubt return
> 2003
> instead of 2002 for a few others. Even after my fix you will need to be
> alert for this.
>
> One solution that appears at first glance to be successful is to
> truncate
> the year down to two digits. This allows both multipliers to be reduced
> by a
> factor of 100 thus greatly reducing the chance of an error. This
> solution
> has problems of its own in that it requires the use of Frac() which can
> also
> cause tiny errors - the very problem we are trying to get rid of. I
> think
> I've got that covered by using Int() after Frac() (inner functions are
> processed first), and then creating a deliberate error so that the 2
> digit
> year will have a surplus rather than missing fraction. Int() will
> restore
> the year to the correct 2 digit value (I think). Just how you expand
> this
> back to 4 digits I'm not sure but it will depend on what software you
> use
> for further processing.
>
> I found that a number of thinly traded issues reported years of 1999 and
> even further back. In most cases I'm sure that this applies to issues
> that
> are only traded once a month or so. If I was you I would use a cutoff
> date
> in the filter so that any issue with less bars than a specified number
> since
> a specified date would be excluded. This should be quite simple to
> construct.
>
> Make sure your exploration covers more periods than your lookback
> period.
> Using LLV(C,65) should ensure that you have no problems but it doesn't
> hurt
> to stipulate 100, 200 or whatever. I seldom use less than 400 for
> anything,
> and even this is marginal (as far as accuracy is concerned) for some
> signals
> using exponential moving averages.
>
> Here is the modified code for the data column.
>
> D:=ValueWhen(1,LLV(C,65)=C,DayOfMonth());
> M:=ValueWhen(1,LLV(C,65)=C,Month());
> Y:=ValueWhen(1,LLV(C,65)=C,Year());
> D*10000+M*100+Int(Frac(Y/100)*100.01);
>
> > I recall there was some discussion on locking into the correct dates
> in
> > the dim and murky past. Do you guys have any further idea why I am
> > getting erratic dates. I use the dd/mm/yyyy date inversion and my
> > database is Australasian.
>
> That will have to suffice until you come up with further problems. Check
> your results carefully.
>
> Regards
>
> Roy
>
>
>
>
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