Displaying 20 results from an estimated 6000 matches similar to: "Numerical integration problem"
2009 Aug 06
2
Convert dataframe to table with counts where column names become row names
Can anyone explain how best to go from a dataframe to a table (or better yet
a new dataframe) of counts, where the row names in the new table (or
dataframe) are the column names of the original df.
start w/
DF1 =
Pos1 Pos2 Pos3 ....
oligo1 G C A
oligo2 U U A
oligo3 G C C
oligo4 C G U
oligo5 A A G
.....
End with
DF2 =
2001 Nov 29
2
plotting (a) confidence intervals (b) standard error
Hi all,
I'm building a plot of the values in tmeant (below) against positions 1 to
5, using matplot.
tmeant looks like this:
case1 case2
pos1 861.8466 818.5909
pos2 961.2841 976.3466
pos3 878.6080 1262.8523
pos4 950.8011 1129.6080
pos5 968.1080 1063.3920
I also have lower (object tl) and upper (object tu) bounds on the
confidence intervals as follows:
tl:
pos1
2010 May 04
1
Avoiding for-loop for splitting vector into subvectors based on positions
Dear all,
I'm trying to optimize code and want to avoid for-loops as much as possible.
I'm applying a calculation on subvectors from a big one, and I get the
subvectors by using a vector of starting positions:
x <- 1:10
pos <- c(1,4,7)
n <- length(x)
I try to do something like this :
pos2 <- c(pos, n+1)
out <- c()
for(i in 1:n){
tmp <- x[pos2[i]:pos2[i+1]]
2007 Jan 19
3
integrate and quadratic forms
Hi all.
I'm trying to numerically invert the characteristic function
of a quadratic form following Imhof's (1961, Biometrika 48)
procedure.
The parameters are:
lambda=c(.6,.3,.1)
h=c(2,2,2)
sigma=c(0,0,0)
q=3
I've implemented Imhof's procedure two ways that, for me,
should give the same answer:
#more legible
integral1 = function(u) {
2010 Jul 06
1
plotmath vector problem; full program enclosed
Here's another example of my plotmath whipping boy, the Normal distribution.
A colleague asks for a Normal plotted above a series of axes that
represent various other distributions (T, etc).
I want to use vectors of equations in plotmath to do this, but have
run into trouble. Now I've isolated the problem down to a relatively
small piece of working example code (below). If you would
2024 Sep 05
3
BUG: atan(1i) / 5 = NaN+Infi ?
On 2024-09-05 4:23 p.m., Leo Mada via R-help wrote:
> Dear R Users,
>
> Is this desired behaviour?
> I presume it's a bug.
>
> atan(1i)
> # 0+Infi
>
> tan(atan(1i))
> # 0+1i
>
> atan(1i) / 5
> # NaN+Infi
There's no need to involve atan() and tan() in this:
> (0+Inf*1i)/5
[1] NaN+Infi
Why do you think this is a bug?
Duncan Murdoch
2024 Sep 06
1
BUG: atan(1i) / 5 = NaN+Infi ?
I expect that atan(1i) = (0 + infinity i) and that atan(1i)/5 = (0 +
infinity i)/5 = (0 + infinity i).
Here's what I get in C:
(0,1) = (0, 1)
atan((0,1)) = (0, inf)
atan((0,1))/5 = (0, inf)
Note the difference between I*infinity = (0,1)*infinity =
(0*infinity,1*infinity) = (NaN,infinity)
and (0,infinity)/5 = (0/5,infinity/5) = (0,infinity).
The former involves multiplying 0 by infinity, which
2005 May 16
1
branch cuts of atan()
Hi
the following gave me a shock:
> atan(2)
[1] 1.107149
> atan(2+0i)
[1] -0.4636476+0i
>
or, perhaps more of a gotcha:
> atan(1.0001+0i)
[1] -0.7853482+0i
> atan(0.9999+0i)
[1] 0.7853482+0i
>
evidently atan()'s branch cuts aren't where I thought they were.
Where do I look for documentation on this?
--
Robin Hankin
Uncertainty Analyst
National
2004 Dec 16
3
Qyery on bark equation in floor0 code
Hi All,
I need some clarifications regarding the mismatch I found in the code
and the specification.
(a) In the specification, the bark(x) equation is given as:
bark(x) = 13.1 atan(.00074x) + 2.24 atan(.0000000158(x^2)) + .0001x
whereas in the code it is given as:
#define toBARK(n)
(13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n))
Which one of these is the proper one ?
(b)
2024 Sep 05
2
BUG: atan(1i) / 5 = NaN+Infi ?
Perhaps
> Inf*1i
[1] NaN+Infi
clarifies why it is *not* a bug.
(Boy, did that jog some long dusty math memories :-) )
-- Bert
On Thu, Sep 5, 2024 at 2:48?PM Duncan Murdoch <murdoch.duncan at gmail.com>
wrote:
> On 2024-09-05 4:23 p.m., Leo Mada via R-help wrote:
> > Dear R Users,
> >
> > Is this desired behaviour?
> > I presume it's a bug.
> >
2024 Sep 05
2
BUG: atan(1i) / 5 = NaN+Infi ?
Dear R Users,
Is this desired behaviour?
I presume it's a bug.
atan(1i)
# 0+Infi
tan(atan(1i))
# 0+1i
atan(1i) / 5
# NaN+Infi
There were some changes in handling of complex numbers. But it looks like a bug.
Sincerely,
Leonard
[[alternative HTML version deleted]]
2024 Sep 05
1
BUG: atan(1i) / 5 = NaN+Infi ?
> complex(real = 0, imaginary = Inf)
[1] 0+Infi
> Inf*1i
[1] NaN+Infi
>> complex(real = 0, imaginary = Inf)/5
[1] NaN+Infi
See the Note in ?complex for the explanation, I think. Duncan can correct
if I'm wrong.
-- Bert
On Thu, Sep 5, 2024 at 3:20?PM Leo Mada <leo.mada at syonic.eu> wrote:
> Dear Bert,
>
> These behave like real divisions/multiplications:
>
2024 Sep 05
2
BUG: atan(1i) / 5 = NaN+Infi ?
atan(1i) -> 0 + Inf i
complex(1/5) -> 0.2 + 0i
atan(1i) -> (0 + Inf i) * (0.2 + 0i)
-> 0*0.2 + 0*0i + Inf i * 0.2 + Inf i * 0i
infinity times zero is undefined
-> 0 + 0i + Inf i + NaN * i^2
-> 0 + 0i + Inf i - NaN
-> NaN + Inf i
I am not sure how complex arithmetic could arrive at another answer.
I advise against messing with infinities... use atan2() if you don't
2024 Sep 05
1
BUG: atan(1i) / 5 = NaN+Infi ?
Dear Bert,
These behave like real divisions/multiplications:
complex(re=Inf, im = Inf) * 5
# Inf+Infi
complex(re=-Inf, im = Inf) * 5
# -Inf+Infi
The real division / multiplication should be faster and also is well behaved. I was expecting R to do the real division/multiplication on a complex number. Which R actually does for these very particular cases; but not when only Im(x) is Inf.
2001 Aug 12
3
gam() and library( modreg )
Hi,
I'm just wonder if there is an R equivalent function of gam() - which
exist in Splus.
Also does anyone know if the library( modreg ), which comes with the
installation file of R 1.3.0 (Windows version), exists in the previous
versions of R (again, Windows version)? Or does one need to install the
library into the previous versions of R explicitly?
Thanks,
Ko-Kang Wang
2024 Sep 06
1
BUG: atan(1i) / 5 = NaN+Infi ?
On 2024-09-06 12:44 a.m., Richard O'Keefe wrote:
> I expect that atan(1i) = (0 + infinity i) and that atan(1i)/5 = (0 +
> infinity i)/5 = (0 + infinity i).
> Here's what I get in C:
> (0,1) = (0, 1)
> atan((0,1)) = (0, inf)
> atan((0,1))/5 = (0, inf)
>
> Note the difference between I*infinity = (0,1)*infinity =
> (0*infinity,1*infinity) = (NaN,infinity)
> and
2000 Nov 26
2
References for the BARK/MEL stuff
Could someone point me to the BARK/MEL tables that these macros (from vorbis/scales.h) are trying to approximate?
#define toBARK(f) (13.1*atan(.00074*(f))+2.24*atan((f)*(f)*1.85e-8)+1e-4*(f))
#define fromBARK(z) (102.*(z)-2.*pow(z,2.)+.4*pow(z,3)+pow(1.46,z)-1.)
#define toMEL(f) (log(1.+(f)*.001)*1442.695)
#define fromMEL(m) (1000.*exp((m)/1442.695)-1000.)
I was wondering if I could come
2006 Mar 28
2
atan2(1,1i)
Hi
?atan2 says that atan2(y,x)=atan(y/x) for x and y numeric or complex
vectors.
Well, I would expect atan2(1,1i) to be equal to atan(-1i), but
> atan2(1,1i)
Error in atan2(y, x) : Non-numeric argument to mathematical function
> R.version
_
platform powerpc-apple-darwin8.5.0
arch powerpc
os darwin8.5.0
system powerpc, darwin8.5.0
2006 Mar 28
2
atan2(1,1i)
Hi
?atan2 says that atan2(y,x)=atan(y/x) for x and y numeric or complex
vectors.
Well, I would expect atan2(1,1i) to be equal to atan(-1i), but
> atan2(1,1i)
Error in atan2(y, x) : Non-numeric argument to mathematical function
> R.version
_
platform powerpc-apple-darwin8.5.0
arch powerpc
os darwin8.5.0
system powerpc, darwin8.5.0
2004 Jan 21
2
derivative of atan(x) and similar functions
Dear R experts.
'D()' function recognizes some of the analitical functions, such as
sin, cos, etc. But I'd like to take analytical derivatives from asin,
atan etc. functions. Are there any R packages providing that features?
Thanks.
--
Timur.