[R] Plot multiple similar equations in r

[Berend Hasselman]

> On 2 Mar 2016, at 22:22, David L Carlson <dcarlson at tamu.edu> wrote:
> 
> Another way would be to use matplot() or matlines():
> 
>> lx<-c(0.4, 0.5, 0.6, 0.7)
>> x <- seq(1, 8, length.out=100)
>> myfun <- function(x, k) {(log(k)-(0.37273*log(x)-1.79389))/0.17941}
>> y <- sapply(lx, function(k) myfun(x, k))
>> matplot(x, a, type="l", col="black", lty=1)
> 
> -

Shouldn't the "a" in the call of matplot  be "y"?

Berend

> ------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
> 
> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Dalthorp, Daniel
> Sent: Wednesday, March 2, 2016 1:05 PM
> To: Jinggaofu Shi
> Cc: r-help at R-project.org (r-help at r-project.org)
> Subject: Re: [R] Plot multiple similar equations in r
> 
> Or, if you want easy labels, you can play around with contour graphs.
> 
> ?contour # will give you info on how to make contour plots
> 
> The basic idea is to construct a matrix of z-values...one z for every
> combination of x and y
> contour(x,y,z)
> 
> The x's would then be the x-values you want in
> (0.37273*log(x)-1.79389))/0.17941 for whatever range of x's you want
> The y's would be values from -5 to 5 (or whatever range you want)
> The z's would be values like 0.4, 0.5, etc. or exp(y + x)
> 
> ?outer # will tell you how to create z from x and y
> 
> x<-seq(1,10,length=100) # values for x-axis
> y<-seq(2, 10, length=100) # values for y-axis
> z<-exp(outer((0.37273*log(x)-1.79389)/0.17941,y,"+"))
> contour(x,y,z,levels=seq(.1,1.1,by=.1))
> 
> -Dan
> 
> On Wed, Mar 2, 2016 at 9:03 AM, Jinggaofu Shi <js3786 at drexel.edu> wrote:
> 
>> Hi, there I am new on R. I want to plot a graph like this.
>> 
>> The curves are created by these equations :
>> (log(0.4)-(0.37273*log(x)-1.79389))/0.17941,
>> (log(0.5)-(0.37273*log(x)-1.79389))/0.17941,
>> (log(0.6)-(0.37273*log(x)-1.79389))/0.17941, etc. The equations are
>> similar, the only difference is the first log(XXX). I already manually draw
>> the graph by repeating plot() for each equation. But I think there must be
>> a way to just assign a simple variable like x<-c(0.4,0.5,0.6,0.7), and then
>> plot all the curves automatically. I tried to use data frame to make a set
>> of equations, but failed. Could somebody help me? Thank you very much!
>> 
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>> and provide commented, minimal, self-contained, reproducible code.
>> 
> 
> 
> 
> -- 
> Dan Dalthorp, PhD
> USGS Forest and Rangeland Ecosystem Science Center
> Forest Sciences Lab, Rm 189
> 3200 SW Jefferson Way
> Corvallis, OR 97331
> ph: 541-750-0953
> ddalthorp at usgs.gov
> 
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> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.