R help - Oct 2007 - reversing perspective plot axis

Hi,

I am trying to create a perspective plot with Time on the x-axis,  
Underlying Price on the y-axis, and Option Price on the z-axis.  But  
I don't like the way my x-axis is setup.  Right now, Time is this  
sequence.

Time = seq(from = 1/52, to = 1, by=1/52)

That results in the x-axis going from 0 at the back, to 1 near the  
foreground corner.(If that makes any sense)  I want to do the exact  
opposite.  When I try this sequence:

Time = seq(from = 1, to = 1/52, by=-1/52)

I get this error message:

Error in persp.default(x = Time, y = S, z = Price, xlab = "Time",  
ylab = "S",  :
	increasing 'x' and 'y' values expected

So it seems that I can't use a descending sequence for my perspective  
plot.  Is that true?  Is there a way to work around this?

persp(x=Time, y=S, z=Price, xlab="Time", ylab="S",
zlab=TypeFlag, ...)

Essentially, what I'm trying to create is something that looks like  
this.

http://www.insightful.com/products/finmetrics/opSensitivity1_lg.gif

You can see how Time on the x-axis diminishes as it moves to the  
foreground corner.

Thanks in advance.

James

On 30 October 2007 at 20:17, James wrote:
| I am trying to create a perspective plot with Time on the x-axis,  
| Underlying Price on the y-axis, and Option Price on the z-axis.  But  

Can't help with persp, but see 
	http://dirk.eddelbuettel.com/code/rquantlib-rgl.html 
for some animated gifs using Rgl and the RQuantLib pricers.

Dirk

-- 
Three out of two people have difficulties with fractions.

A simple approach is to swap x and y and rotate the theta parameter -90
degrees (play around with this until it is what you want).

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111
 
 
> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of James
> Sent: Tuesday, October 30, 2007 8:17 PM
> To: r-help at r-project.org
> Subject: [R] reversing perspective plot axis
> 
> Hi,
> 
> I am trying to create a perspective plot with Time on the 
> x-axis, Underlying Price on the y-axis, and Option Price on 
> the z-axis.  But I don't like the way my x-axis is setup.  
> Right now, Time is this sequence.
> 
> Time = seq(from = 1/52, to = 1, by=1/52)
> 
> That results in the x-axis going from 0 at the back, to 1 
> near the foreground corner.(If that makes any sense)  I want 
> to do the exact opposite.  When I try this sequence:
> 
> Time = seq(from = 1, to = 1/52, by=-1/52)
> 
> I get this error message:
> 
> Error in persp.default(x = Time, y = S, z = Price, xlab = 
> "Time", ylab = "S",  :
> 	increasing 'x' and 'y' values expected
> 
> So it seems that I can't use a descending sequence for my 
> perspective plot.  Is that true?  Is there a way to work around this?
> 
> persp(x=Time, y=S, z=Price, xlab="Time", ylab="S",
zlab=TypeFlag, ...)
> 
> Essentially, what I'm trying to create is something that 
> looks like this.
> 
> http://www.insightful.com/products/finmetrics/opSensitivity1_lg.gif
> 
> You can see how Time on the x-axis diminishes as it moves to 
> the foreground corner.
> 
> Thanks in advance.
> 
> James
> 
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