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<FONT face=Arial
size=2>Robin:
<FONT face=Arial
size=2>
Lets just end this
thread. But see my note below
<FONT face=Arial
size=2>
Why don't you speak
to an academic mathematician about this.
<FONT face=Arial
size=2>
<FONT face=Arial
size=2>Lionel
<FONT face=Tahoma
size=2>-----Original Message-----From: Robin Hood
[mailto:robinhood@xxxxxxxx] Sent: Monday, January 06, 2003 3:11
PMTo: Metastockusers@xxxxxxxxxxxxxxxSubject: Re:
[Metastockusers] RE:Re: Bar Count since certain date
Hi Lionel
As acutely you note, my old books of mathemathics lie behind Peanuts'
comics, I admit..
I don't understand perfectly what you mean. This is the only certain thing.
For this, reading one of these books, I found some little examples and now I'll
report here. Maybe you can help me with the contents.
Now, a parabola (I translate with my own hands.. :-( ) is the geometrical
place of equidistant points from a fixed point (fuoco = fire in italian)
and from a fixed straight (retta direttrice = straight director
?). <FONT
color=#ff0000>*** the locus of point that are equi distant from a fixed point is
a circle NOT a parabola.
The general formula for the parabola is:
y = ax^2 + bx +c
where "a", "b", "c" are arbitrary constants and "a" not equal to
zero.
Let's determine a, b, c of the general formula (that's let's determine the
whole formula) for the following three points:
A (-1,10)
B (-2,1)
C (-1/2,6)
We have to resolve the system:
10 = a - b - c
1 = 4a + 2b + c
6 = 1/4 a - 1/2 b +c
Resolving, we have that:
a = 2
b = -5
c = 3
That's the formula of our parabola:
y = 2x^2 - 5x + 3
(at this point, we could also find the coordinates of fire, vertix,
simmetry axis by using their fixed relationship with the parameters)
Circle is a particular case of the ellypse: the geometrical place for which
is constant the sum of distances from two fixed points (fires). IN the circle
case, the fire have the same coordinates. Something different from the parabola
(as different is its formula...).
It's time to take in hand my comics, now. Their meant,
fortunately, don't change with latitudes :-)
For who understands Italian or has the patience of translate... here is a
link where focus mi purpose
<A
href="http://www.performancetrading.it/AT/Evolventi/EPIndex.htm">http://www.performancetrading.it/AT/Evolventi/EPIndex.htm
Exist also a program that makes parabolas...
<A
href="http://www.tk-it.com/index.htm">http://www.tk-it.com/index.htm
best regards
robin
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----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Lionel
Issen
To: <A
title=Metastockusers@xxxxxxxxxxxxxxx
href="mailto:Metastockusers@xxxxxxxxxxxxxxx">Metastockusers@xxxxxxxxxxxxxxx
Sent: Sunday, January 05, 2003 11:00
PM
Subject: RE: [Metastockusers] RE:Re: Bar
Count since certain date
<FONT face=Arial
size=2>Robin:
<FONT face=Arial
size=2>
You're English is
fine, it's certainly better than my Italian, which is
zero.
<FONT face=Arial
size=2>
I think that I
understand what you are trying to say. The problem may be is that you
don't understand the relationship between mathematics and curve fitting
(sometimes called statistics).
<FONT face=Arial
size=2>
At the web
sites, the examples are so set up that the the parabola is
predefined and predetermined. Two of the points are at the end of the latus
rectum, and the third point is at the vertex. If you take 3 points so that the
the perpendicular bisector of the line joining the first and third points does
not intersect the middle point. then these 3 points wont define a
parabola, they will define a circle.
<FONT face=Arial
size=2>
The figures at the
web site predefines the parabola. Referring to the figure at the 3rd web
site. in general
FP1 <>
P1D1
<FONT face=Arial
size=2>
As I wrote
earlier, data points do not lie on nice smooth curves. When curve fitting
data, we have to decide what kind of curve fits the data and then try to fit
such a curve to the data. For these reasons we need many more points
than the minimum needed to define the curve.
<FONT face=Arial
size=2>
If you have access
to an academic library look up some books on curve fitting. Try to find
some that were written before the days of computers. Let me know what
you find.
<FONT face=Arial
size=2>
<FONT face=Arial
size=2>Lionel
<FONT face=Arial
size=2>
<FONT face=Arial
size=2>
<FONT
face=Tahoma size=2>-----Original Message-----From: Robin Hood
[mailto:robinhood@xxxxxxxx] Sent: Sunday, January 05, 2003 9:51
AMTo: Metastockusers@xxxxxxxxxxxxxxxSubject: Re:
[Metastockusers] RE:Re: Bar Count since certain date
Lionel,
my bad English doesn't help us... :-)
Look at rhis site where there are a full description of what you already
know, I think
<A
href="http://schools.spsd.sk.ca/mount/Hoffman/MathC30/Parabola/parabola.htm#trinomial">http://schools.spsd.sk.ca/mount/Hoffman/MathC30/Parabola/parabola.htm#trinomial
I find this about autocad (I don't use it)
<A
href="http://xarch.tu-graz.ac.at/autocad/news/lisp_progs/msg00013.html">http://xarch.tu-graz.ac.at/autocad/news/lisp_progs/msg00013.html
and anyway the results of this search say that wee need three points for
building a parabola (by solving a system of equations I remember - maybe :-)
)
<A
href="http://www.google.it/search?q=build+parabola+three+points&hl=it&lr=&ie=UTF-8&oe=UTF-8&start=0&sa=N">http://www.google.it/search?q=build+parabola+three+points&hl=it&lr=&ie=UTF-8&oe=UTF-8&start=0&sa=N
I hope your math knowledge is better than mine and unserstand what I'd
like to say.
robin
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----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Lionel
Issen
To: <A
title=Metastockusers@xxxxxxxxxxxxxxx
href="mailto:Metastockusers@xxxxxxxxxxxxxxx">Metastockusers@xxxxxxxxxxxxxxx
Sent: Sunday, January 05, 2003 3:13
PM
Subject: RE: [Metastockusers] RE:Re:
Bar Count since certain date
<FONT face=Arial
size=2>Robin:
<FONT face=Arial
size=2>
Can you direct
me to the portion of the cited web site where it says that 3 points are
sufficient to define a parabola? Three points would be sufficient to define
a parabola if you know the semi latus rectum (factor F
below).
<FONT face=Arial
size=2>
Please bear with
me. While both the circle and the parabola are conic sections their
equations are different.
<FONT face=Arial
size=2>
Equation of
Circle : X**2 + Y**2 = R**2 R is the
radius
<FONT face=Arial
size=2>
Equation of
parabola: Y**2 =
4FX F is
the semi latus rectum
<FONT face=Arial
size=2>
Here is a little
exercise you can do. All you need are two pieces of paper, a
pencil, a compass, a straight edge (a ruler will do) and maybe an
eraser.
Place 3 points
on a piece of paper, they must not be on a straight line. Call them A, B,
and C. Draw the lines A-B and B-C. Bisect these 2 lines and draw the
perpendicular bisectors. the bisectors will meet at the center of the
circle. Next select any other 3 points on the circle and repeat this little
exercise. These bisectors will also meet at the center of the
circle. Before the days of electronic navigation, the basis
of this method was used by navigators near shore or in narrow
channels to locate the position of the vessel.
<FONT face=Arial
size=2>
If you draw a
parabola and select two or more sets of three points on the
parabola and repeat the exercise, the bisectors will not meet at the same
place.
<FONT face=Arial
size=2>
If you have any
further questions please write me privately
<FONT face=Arial
size=2>
<FONT face=Arial
size=2>Lionel
<FONT face=Arial
size=2>
<FONT face=Arial
size=2>
<FONT face=Arial
size=2>
<FONT
face=Tahoma size=2>-----Original Message-----From: Robin Hood
[mailto:robinhood@xxxxxxxx] Sent: Sunday, January 05, 2003 4:51
AMTo: Metastockusers@xxxxxxxxxxxxxxxSubject: Re:
[Metastockusers] RE:Re: Bar Count since certain date
Hi Lionel
Three points are sufficient as parabola is made by tho points
equidistanced (? in english ?) form another one.
<A
href="http://www.xahlee.org/SpecialPlaneCurves_dir/Parabola_dir/parabola.html">http://www.xahlee.org/SpecialPlaneCurves_dir/Parabola_dir/parabola.html for
examples (by google).
Here is a chart form an Italian site which I don't name because of
netiquette (I think...). They build a parabola from three points, in effect.
It's the same effect I'd like to reproduce with Metastock... but the trouble
are the input dates (x coordinates) :-(
robin
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----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
Lionel
Issen
To: <A
title=Metastockusers@xxxxxxxxxxxxxxx
href="mailto:Metastockusers@xxxxxxxxxxxxxxx">Metastockusers@xxxxxxxxxxxxxxx
Sent: Saturday, January 04, 2003 4:57
PM
Subject: RE: [Metastockusers] RE:Re:
Bar Count since certain date
Three points
always define a circle. I think that you need at least 4 points to
define a parabola. When curve fitting a parabola you need more than 4
points as data points always have some noise, they don't fall on a nice
smooth curve.
<FONT
face=Tahoma size=2>-----Original Message-----From: Robin Hood
[mailto:robinhood@xxxxxxxx] Sent: Saturday, January 04, 2003
8:25 AMTo: Metastockusers@xxxxxxxxxxxxxxxSubject:
Re: [Metastockusers] RE:Re: Bar Count since certain
date
Hi Group
Thanks to Spyros for his formula.
In order to build a parabolic trend-line, I need three points
(geometry requires it). It means three x,y (date,
price) coordinates.
The problem is that metastock accepts only six inputs (in oder to
define dates I need 3+3+3=9 inputs :-( ).
Is there another way to make this?
Now, the formula inputs are as follows, but I'd like to
change the numbers with dates since I don't understand very well and
immediately their sequence
x1:=Input("point 1 : x1",-100000000,100000000,0);y1:=Input("
y1",-100000000,100000000,0);x2:=Input("point 2 :
x2",-100000000,100000000,0);y2:=Input("
y2",-100000000,100000000,0);x3:=Input("Point 3:
x3",-100000000,100000000,0);y3:=Input("
y3",-100000000,100000000,0);
Thanks in advance, Robin
<BLOCKQUOTE
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----- Original Message -----
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From:
SR
To: <A
title=Metastockusers@xxxxxxxxxxxxxxx
href="mailto:Metastockusers@xxxxxxxxxxxxxxx">Metastockusers@xxxxxxxxxxxxxxx
Sent: Saturday, January 04, 2003
2:24 PM
Subject: [Metastockusers] RE:Re:
Bar Count since certain date
bruneski came up with a variation of my approach
which is corrects somefailures of my version.So I suggest trying
this
one:{BarsSinceDate}d:=Input("Day",1,31,1);m:=Input("Month",1,12,1);y:=Input("Year",1920,2030,2002);mydate:=
10000*y + 100*m + d;date:= 10000*Year() + 100*Month() +
DayOfMonth();count:=BarsSince(mydate<=date); {use '<' if first
day is not to becounted}count:=count +
Cum(If(count=0,1,0));countTo unsubscribe
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