[R-sig-finance] question on GBS

[s viswanath]

hello r experts,

i am tryingto back out implied volatility from some options and am struggling to get an understanding of 
tol(erence) and how to set it as shown below.

 GBSVolatility(price, TypeFlag, S, X, Time, r, b, tol, maxiter)

Could someone please provide and example of what tolerence means and how to set it?

fyi below is the explanation for this in rhelp
maxiter, tol: [GBSVolatility*] - 
the maximum number of iterations and the tolerance to          compute the root of the GBS volatility equation, see          'uniroot'. 

Best,

Sri
-----Original Message-----
From: r-sig-finance-request at stat.math.ethz.ch
To: r-sig-finance at stat.math.ethz.ch
Date: Thu, 4 Nov 2004 12:29:30 +0100
Subject: R-sig-finance Digest, Vol 6, Issue 2

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Today's Topics:

   1. RMetrics functions... (Vincent C. Fulco)
   2. Re: RMetrics functions... (Paul DeBruicker)


----------------------------------------------------------------------

Message: 1
Date: Wed, 03 Nov 2004 13:00:27 -0500
From: "Vincent C. Fulco" <vfulco at optonline.net>
Subject: [R-sig-finance] RMetrics functions...
To: r-sig-finance at stat.math.ethz.ch
Message-ID: <41891CBB.2070007 at optonline.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Dear R-finance list-

Can anyone tell me if they are using Rmetrics economagicImport and 
yahooImport functions on a regular basis?  I've attempted to use them 
and followed the instructions religiously and I keep receiving an error 
message "No Internet Access".

Thanks for your time.


Vince Fulco



------------------------------

Message: 2
Date: Wed, 3 Nov 2004 13:35:59 -0500
From: Paul DeBruicker <paul at woodgasllc.com>
Subject: Re: [R-sig-finance] RMetrics functions...
To: "Vincent C. Fulco" <vfulco at optonline.net>
Cc: r-sig-finance at stat.math.ethz.ch
Message-ID: <34C01FCA-2DC7-11D9-8C75-0003931A8C1A at woodgasllc.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed

Set the "try" flag to FALSE in the import function

Historical.data<-yahooImport(query=query, try=FALSE);


It will prevent the function from checking for internet access and see 
if it works without confirmation.  Setting "try" to FALSE solves that 
problem on my Mac.



On Nov 3, 2004, at 1:00 PM, Vincent C. Fulco wrote:

> Dear R-finance list-
>
> Can anyone tell me if they are using Rmetrics economagicImport and 
> yahooImport functions on a regular basis?  I've attempted to use them 
> and followed the instructions religiously and I keep receiving an 
> error message "No Internet Access".
>
> Thanks for your time.
>
>
> Vince Fulco
>
> _______________________________________________
> R-sig-finance at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-sig-finance
>



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