Displaying 20 results from an estimated 56 matches for "kahan".
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kagan
2003 Dec 30
1
Accuracy: Correct sums in rowSums(), colSums() (PR#6196)
....14.73)
With the introduction of the functions rowSums(), colSums(), rowMeans() and
colMeans() in R1.5.0, function "SEXP do_colsum(SEXP call, SEXP op, SEXP args,
SEXP rho)" was added to perform the fast summations. We have an excellent
opportunity to improve the accuracy by implementing Kahan summation here.
Kahan summation is described in
@article{ goldberg91what,
author = "David Goldberg",
title = "What Every Computer Scientist Should Know About Floating-Point
Arithmetic",
journal = "ACM Computing Surveys",
volume = "23",...
2019 Feb 19
4
code for sum function
The algorithm does make a differece. You can use Kahan's summation
algorithm (https://en.wikipedia.org/wiki/Kahan_summation_algorithm) to
reduce the error compared to the naive summation algorithm. E.g., in R
code:
naiveSum <-
function(x) {
s <- 0.0
for(xi in x) s <- s + xi
s
}
kahanSum <- function (x)
{
s <- 0.0
c &...
2020 Apr 07
1
issues with Time Machine - did macOS change how they handle things?
...ean parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
unix password sync = yes
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
passwd program = /usr/bin/passwd %u
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
# This boolean cont...
2010 Jun 10
0
No subject
...n parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
unix password sync = yes
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
passwd program = /usr/bin/passwd %u
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
# This boolean...
2009 Dec 04
0
can not write to subfolders of samba share, just the root of it
...ter to something
higher.
# Do something sensible when Samba crashes: mail the admin a backtrace
####### Authentication #######
; passdb backend = tdbsam
; guest account = nobody
# For Unix password sync to work on a Debian GNU/Linux system, the
following
# parameters must be set (thanks to Ian Kahan
<<kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
############ Misc ############
# Most people will find that this option gives better performance.
# See smb.conf(5) and
/usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/spee...
2019 Feb 19
0
code for sum function
This SO question may be of interest:
https://stackoverflow.com/questions/38589705/difference-between-rs-sum-and-armadillos-accu/
which points out that sum() isn't doing anything fancy *except* using
extended-precision registers when available. (Using Kahan's algorithm
does come at a computational cost ...)
On 2019-02-19 2:08 p.m., William Dunlap via R-devel wrote:
> The algorithm does make a differece. You can use Kahan's summation
> algorithm (https://en.wikipedia.org/wiki/Kahan_summation_algorithm) to
> reduce the error compared...
2009 Dec 01
1
Password Change from Windows machines ("You do not have permission to change your password")
...less "You do not have permission to change your
password" dialog box, and sent me on a wild goose chase.
The comments in the smb.conf that come with Ubuntu say this:
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan
<<kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
passwd program = /usr/bin/passwd %u
passwd chat = *Enter\snew\s*\spassword:* %n\n
*Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
# This boolea...
2006 Feb 19
2
Computing means, variances and sums
...3614e-18
> z <- sum(rep(0.02, 10))/10 -0.02
> 10*z^2/9
[1] 1.3374513502689138e-35
and so the non-zero variance is arising from (x[i] - mean) being non-zero.
(I did check that was what was happening at C level.)
There has been talk of other ways to arrange these computations, for
example Kahan summation and Welford's algorithm (see Chan & Lewis, 1979,
CACM 22, 526-531 and references therein). However, R already used the
two-pass algorithm which is the most accurate (in terms of error bounds)
in that reference.
Why are most people seeing 0? Because the way computation is don...
2019 Sep 02
2
AVX2 codegen - question reg. FMA generation
On Mon, 2 Sep 2019 at 16:59, Roman Lebedev <lebedev.ri at gmail.com> wrote:
>
> It appears you need 'reassoc' on fmul/fadd:
> https://godbolt.org/z/nuTzx2
Thanks very much, that was it. Either that or providing
-enable-unsafe-fp-math to llc yielded FMAs. I didn't expect this since
using FMAs here instead of mul/add appears to be safer (the reverse is
unsafe).
~ Uday
2018 Mar 16
1
Discrepancy: R sum() VS C or Fortran sum
My simple functions were to compare the result with the gfortran
compiler sum() function. I thought that the Fortran sum could not be
less precise than R. I was wrong. I am impressed. The R sum does in fact
match the result if we use the Kahan algorithm.
P.
I am glad to see that R sum() is more accurate than the gfortran
compiler sum.
On 16/03/18 11:37 AM, luke-tierney at uiowa.edu wrote:
> Install the gmp package, run your code, and then try this:
>
> bu <- gmp::as.bigq(u)
> bs4 <- bu[1] + bu[2] + bu[3] + bu[4] + b...
2016 Mar 15
1
Installing onto Windows
...; # password with the SMB password when the encrypted SMB password in the
> > # passdb is changed.
> > unix password sync = yes
> >
> > # For Unix password sync to work on a Debian GNU/Linux system, the
> > following
> > # parameters must be set (thanks to Ian Kahan
> > <<kahan at informatik.tu-muenchen.de> for
> > # sending the correct chat script for the passwd program in Debian
> Sarge).
> > passwd program = /usr/bin/passwd %u
> > passwd chat = *Enter\snew\s*\spassword:* %n\n
> > *Retype\snew\s*\spassword:* %n...
2008 Mar 29
1
Access Denied - How to solve it?
...n parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
; unix password sync = no
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan
<<kahan@informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
;passwd program = /usr/bin/passwd %u
;passwd chat = *Enter\snew\sUNIX\spassword:* %n\n
*Retype\snew\sUNIX\spassword:* %n\n
*passwd:*password\supdated\ssuccessfully* ....
2016 Feb 18
1
Samba + ldap + cannot find domain
...n parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
unix password sync = yes
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
passwd program = /usr/sbin/smbldap-passwd -u %u
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
# T...
2018 Sep 24
3
Debian Stretch AMD64 only, Samba 4.9.1 Available TESTING
Hai Daniel,
Yes yes.. As you can see in my change log.
( found here, http://downloads.van-belle.nl/samba4/Buildlogs/stretch-experimental/ )
>From my changelog.
samba (2:4.9.0+dfsg-1.1nmu~deb9) stretch; urgency=medium .
* Non-maintainer upload.
* Rebuild from Debian stretch from Debian Experimental
* Bump build-depends cmocka 1.1.2
* enabled --enable-spotlight to make TimeMachine work
2010 Apr 13
1
Users in group cannot rename or delete files/folder owned by the group
...n parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
unix password sync = yes
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan
<<kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
passwd program = /usr/bin/passwd %u
passwd chat = *Enter\snew\s*\spassword:* %n\n
*Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
# This boolean...
2016 Mar 15
0
Installing onto Windows
...attempts to sync the Unix
> # password with the SMB password when the encrypted SMB password in the
> # passdb is changed.
> unix password sync = yes
>
> # For Unix password sync to work on a Debian GNU/Linux system, the
> following
> # parameters must be set (thanks to Ian Kahan
> <<kahan at informatik.tu-muenchen.de> for
> # sending the correct chat script for the passwd program in Debian Sarge).
> passwd program = /usr/bin/passwd %u
> passwd chat = *Enter\snew\s*\spassword:* %n\n
> *Retype\snew\s*\spassword:* %n\n *password\supdated\ssucce...
2019 Jan 31
2
Samba and UFW
On Thu, 31 Jan 2019 11:43:37 -0500
<mmcg29440 at frontier.com> wrote:
> OK Guys this where we are now. The hostname on the Mint 19.1 PC was a
> combination of the user name and the PC model. I changed it to
> "radio". That plus the user name gives "martin at radio". That is
> twelve characters long. No change. Still not able to mount network.
>
>
2019 May 17
1
Moving home directories to another location leads to NT_STATUS_ACCESS_DENIED listing
...using.
# This boolean parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<kahan at informatik.tu-muenchen.de[mailto:%20kahan at informatik.tu-muenchen.de]> for
# sending the correct chat script for the passwd program in Debian Sarge).
# This boolean controls whether PAM will be used for password changes
# when requested by an SMB client instead of the progra...
2019 Feb 09
0
Linux Mint 19.1, Samba 4.7.6 & WIndows 10
...parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
unix password sync = yes
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
passwd program = /usr/bin/passwd %u
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
# This boolean co...
2010 Feb 08
2
Noob (it seems) can't get XP client to join Samba Domain
...n parameter controls whether Samba attempts to sync the Unix
# password with the SMB password when the encrypted SMB password in the
# passdb is changed.
unix password sync = yes
# For Unix password sync to work on a Debian GNU/Linux system, the following
# parameters must be set (thanks to Ian Kahan <<
kahan at informatik.tu-muenchen.de> for
# sending the correct chat script for the passwd program in Debian Sarge).
passwd program = /usr/bin/passwd %u
passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:*
%n\n *password\supdated\ssuccessfully* .
# This boolean...