[PD] cumulative distribution?

[Jacob Last]

In fact I don't think you can compute the cumulative gaussian
distribution from a closed formula...

i think that a sigmoid function might be better suited than the
hyperbolic tangent.... take a look at
http://en.wikipedia.org/wiki/Sigmoid_function for more. I'm not at
home so can't open your patch; sorry if I have the wrong idea.

Best,

Jacob

On 11/9/05, pete mcpartlan <petemcpartlan at yahoo.co.uk> wrote:
> cdf i think, when i said flat at both ends i meant horizontal. so yeah,
> an s curve not a bell curve-
>
> so yes cumulative gaussian distibution -i think...
>
> sorry to clog up the list with my mathematic incompetency, but how do i
> integrate the pdf?
>
> thanks
>
> pete
>
> Charles Henry wrote:
>
> >hold on...what kind of distribution are you looking for?  the
> >expression is pdf for a probability density function that flattens out
> >at both ends.  the cdf (cumulative density) is obtained by integrating
> >the pdf-this is the stretched 's'
> >Simulating random variables by the inversion method involves taking
> >the integral of your chosen pdf, and putting the values in a table.
> >Then you can pick numbers between 0 and 1 and look up the random
> >variable's value.  So, what distribution do you want?
> >
> >Chuck
> >
> >On 11/9/05, pete mcpartlan <petemcpartlan at yahoo.co.uk> wrote:
> >
> >
> >>thanks Tebjan,
> >>
> >>but...its not half a cosine because it has to flatten out at both ends.
> >>
> >>and secondly i have no idea how to take an equation like that and
> >>implement that in pd... maybe i didnt explain that i'm not too good at
> >>all that maths stuff...
> >>
> >>thanks,
> >>
> >>pete
> >>
> >>Tebjan Halm wrote:
> >>
> >>
> >>
> >>>>>(cos(x) + 1) * c with x inside the range -Pi to 0 and c is a constant
> >>>>>that defines the output range of the curve 0 to c ...
> >>>>>
> >>>>>
> >>>sorry, the output range will be 0 to 2*c ... because the cos range -1
> >>>to 1
> >>>gets shifted upwards by the +1 to 0..2 and c scales this range ...
> >>>
> >>>pete mcpartlan schrieb:
> >>>
> >>>
> >>>
> >>>>hello,
> >>>>
> >>>>i need help with a maths problem... i am trying to plot a cumulative
> >>>>distribution curve to weight random. I have a [random] that feeds
> >>>>into a chain of [moses], sililar to the markov chain example but what
> >>>>i want to do is have a table dump into the right inlet of each moses
> >>>>changing the weighting. so far so good. what i need help with is the
> >>>>curve which needs to make it more likely for the next result to be
> >>>>near the  same position. the attatched patch has an array with the
> >>>>sort of function it should be... like an s stetched at both ends...
> >>>>is there a way i can do this with expr? or am i going to have to type
> >>>>out a list for each state? i'm sure this is probably quite a simple
> >>>>maths problem... but beyond me... or other ideas? might it be simpler
> >>>>to have a longer array with the curve is then plotted at different
> >>>>points back into the array... but considering i'm probably going to
> >>>>have 16+ of these and other stuff i want to make it as simple as
> >>>>possible....
> >>>>
> >>>>thanks in advance and apologies for rambling a bit..
> >>>>
> >>>>pete
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> >>--
> >>~~~~~~~~~~~~~~~~~~~~~~~~~
> >>www.140worthing.karoo.net
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> >>
> >>
> >>
> >>
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> >
> >
> >--
> >Charles Zachary Henry
> >
> >anti.dazed.med
> >Med student who needs a Mickey's
> >
> >
> >
>
> --
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> www.140worthing.karoo.net
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