see below!
On Sat, Apr 14, 2012 at 4:05 PM, Gabor Grothendieck
<ggrothendi...@gmail.com> wrote:
> On Fri, Apr 13, 2012 at 9:50 PM, Kjetil Halvorsen
> <kjetilbrinchmannhalvor...@gmail.com> wrote:
>> I am experimenting with rSymPy, and it seems to work nice.
>>
>>
>> However, I dislike the need to wrap all sympy expressions within
>> quotes, it leads to ugly calls like
>> library(rSymPy)
>> Var("x,y,z")
>> sympy("(x+y)**2")
>> and so on.
>
> Suggest you review the rSymPy home page which illustrates how to use
> the Sym interface, e.g.
>
>> library(rSymPy)
>> x <- Var("x")
>> y <- Var("y")
>> (x+y)*(x+y)
> [1] "(x + y)**2"
Thanks!
But there seems to be errors in that interface. First:
> sessionInfo()
R version 2.15.0 (2012-03-30)
Platform: x86_64-pc-linux-gnu (64-bit)
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
[7] LC_PAPER=C LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] rSymPy_0.2-1.1 rJython_0.0-2 rjson_0.2.8 rJava_0.9-3 pnmath_0.0-3
[6] MASS_7.3-17
loaded via a namespace (and not attached):
[1] compiler_2.15.0 fortunes_1.5-0 tools_2.15.0
>
> x <- Var('x')
> y <- x*x
> deriv(y, x, 2)
[1] "2"
> z <- exp(-x)
Error in match(.Generic, transtab[, 1], nomatch = 0) :
object 'transtab' not found
> Math.Sym
function (x, ...)
{
idx <- match(.Generic, transtab[, 1], nomatch = 0)
fn <- if (idx > 0)
transtab[idx, 3]
else .Generic
Sym(fn, "(", x, ")")
}
<bytecode: 0x31a42b0>
<environment: namespace:rSymPy>
>
Kjetil
>
>
> --
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
> tel: 1-877-GKX-GROUP
> email: ggrothendieck at gmail.com
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