Displaying 20 results from an estimated 2000 matches similar to: "[LLVMdev] Unrolling power sum calculations into constant time expressions"
2010 Nov 23
1
[LLVMdev] Unrolling loops into constant-time expressions
Hello,
I've come across another example:
I'm compiling with
clang -S -emit-llvm -std=gnu99 -O3
clang version 2.9 (trunk 118238)
Target: x86_64-unknown-linux-gnu
Thread model: posix
I take the code:
int loops(int x) {
int ret = 0;
for(int i = 0; i < x; i++) {
for(int j = 0; j < x; j++) {
ret += 1;
}
}
return ret;
}
and the
2010 Nov 23
2
[LLVMdev] Unrolling an arithmetic expression inside a loop
Hello,
I've been redirected from cfe-dev, as code optimizations in clang are
done in llvm layer.
I'm investigating how optimized code clang generates, and have come
across such an example:
I have two procedures:
void exec0(const int *X, const int *Y, int *res, const int N) {
int t1[N],t2[N],t3[N],t4[N],t5[N],t6[N];
for(int i = 0; i < N; i++) {
t1[i] = X[i]+Y[i];
2018 Jul 10
9
[PATCH 0/7] PowerPC64 performance improvements
The following series adds initial vector support for PowerPC64.
On POWER9, flac --best is about 3.3x faster.
Amitay Isaacs (2):
Add m4 macro to check for C __attribute__ features
Check if compiler supports target attribute on ppc64
Anton Blanchard (5):
configure.ac: Remove SPE detection code
configure.ac: Add VSX enable/disable
configure.ac: Fix FLAC__CPU_PPC on little endian, and add
2014 Nov 11
3
[LLVMdev] supporting SAD in loop vectorizer
----- Original Message -----
> From: "Dibyendu Das" <Dibyendu.Das at amd.com>
> To: "Hal Finkel" <hfinkel at anl.gov>, "Renato Golin" <renato.golin at linaro.org>
> Cc: llvmdev at cs.uiuc.edu
> Sent: Tuesday, November 4, 2014 12:15:12 PM
> Subject: RE: [LLVMdev] supporting SAD in loop vectorizer
>
> Here's the simple SAD
2014 Nov 11
4
[LLVMdev] supporting SAD in loop vectorizer
----- Original Message -----
> From: "James Molloy" <james at jamesmolloy.co.uk>
> To: "Hal Finkel" <hfinkel at anl.gov>
> Cc: "Dibyendu Das" <Dibyendu.Das at amd.com>, llvmdev at cs.uiuc.edu
> Sent: Tuesday, November 11, 2014 8:21:37 AM
> Subject: Re: [LLVMdev] supporting SAD in loop vectorizer
>
>
> If you'd like to
2001 May 03
2
wineserver: /root/.wine/config is not a valid registry file
Hi!
When I'm trying to run wine (I've tried many compilations), I got something
like that:
wineserver: /root/.wine/config is not a valid registry file
Why I'm not using /etc/wine.conf, /usr/etc/wine.conf or
/usr/local/etc/wine.conf? Because wineserver wants only
$HOME/.wine/config...
When I delete this file wineserver 'says' that I don't have configuration
file (even
2014 Nov 04
3
[LLVMdev] supporting SAD in loop vectorizer
----- Original Message -----
> From: "Renato Golin" <renato.golin at linaro.org>
> To: "Dibyendu Das" <Dibyendu.Das at amd.com>
> Cc: llvmdev at cs.uiuc.edu
> Sent: Tuesday, November 4, 2014 5:23:30 AM
> Subject: Re: [LLVMdev] supporting SAD in loop vectorizer
>
> On 4 November 2014 11:06, Das, Dibyendu <Dibyendu.Das at amd.com> wrote:
2008 Aug 15
2
Design-consistent variance estimate
Dear List:
I am working to understand some differences between the results of the
svymean() function in the survey package and from code I have written
myself. The results from svymean() also agree with results I get from
SAS proc surveymeans, so, this suggests I am misunderstanding something.
I am never comfortable with "I did what the software" does mentality, so
I am working to
2012 Oct 18
7
summation coding
I would like to code the following in R: a1(b1+b2+b3) + a2(b1+b3+b4) +
a3(b1+b2+b4) + a4(b1+b2+b3)
or in summation notation: sum_{i=1, j\neq i}^{4} a_i * b_i
I realise this is the same as: sum_{i=1, j=1}^{4} a_i * b_i - sum_{i=j} a_i
* b_i
would appreciate some help.
Thank you.
--
View this message in context: http://r.789695.n4.nabble.com/summation-coding-tp4646678.html
Sent from the R
2011 Mar 14
1
Math characters in column heading using latex() in Hmisc
Hi Everybody
I want to print a latex table containing math characters in the column
heading
These are the formulae I want to use as column headings. It prints OK from
TeX
$\sum_{i}\sum_{j}C_{P,i,j,y}\times\mathit{FC}_{i}$, $XU_{alt,y}$, $n$,
$\bar{C}_{P,y}$
My plan was to create a character vector with these and later rbind the
values to them. When I create the vector like:
2009 May 18
8
Simple plotting errors
Dear R Users,
I have 12 data frames, each of 12 rows and 2 columns.
e.g. FeketeJAN
MEAN SUM_
AMAZON 144.4997874 68348.4
NILE 5.4701955 1394.9
CONGO 71.3670036 21196.0
MISSISSIPPI 18.9273250 6511.0
AMUR 1.8426874 466.2
PARANA 58.3835497 13486.6
YENISEI 1.4668313 592.6
OB 1.4239179 559.6
LENA 0.9342164
2009 May 01
2
Double summation limits
Dear R experts
I need to write a function that incorporates double summation, the problem
being that the upper limit of the second summation is the index of the first
summation, i.e:
sum_{j=0}^{x} sum_{i=0}^{j} choose(i+j, i)
where x variable or constant, doesn't matter.
The following code obviously doesn't work:
f=function(x) {j=0:x; i=0:j; sum( choose(i+j,i) ) }
Can you help?
Thanks
2009 Oct 17
2
Recommendation on a probability textbook (conditional probability)
I need to refresh my memory on Probability Theory, especially on
conditional probability. In particular, I want to solve the following
two problems. Can somebody point me some good books on Probability
Theory? Thank you!
1. Z=X+Y, where X and Y are independent random variables and their
distributions are known.
Now, I want to compute E(X | Z = z).
2.Suppose that I have $I \times J$ random number
2006 Oct 21
2
problem with mode of marginal distriubtion of rdirichlet{gtools}
Hi all,
I have a problem using rdirichlet{gtools}.
For Dir( a1, a2, ..., a_n), its mode can be found at $( a_i -1)/ (
\sum_{i}a_i - n)$;
The means are $a_i / (\sum_{i} a_i ) $;
I tried to study the above properties using rdirichlet from gtools. The code
are:
##############
library(gtools)
alpha = c(1,3,9) #totoal=13
mean.expect = c(1/13, 3/13, 9/13)
mode.expect = c(0, 2/10, 8/10) #
2004 Dec 09
3
surf.ls
Hello,
I am looking into description of surf.ls(spatial)
and see under value $beta - the coefficients.
When I use polynomial of degree 2 to fit surface
I expect to get 4 coefficients:
z = a_1 x^2 + a_2 xy + a_3 y^2 + a_4
What do beta really stand for and why do I get
$beta vector of length 6?
Thakns,
Mark
2012 Aug 16
1
sum predictions by hand
Hi,
If I do a standard svm regression with e1071
x <- seq(0.1, 5, by = 0.05)
y <- log(x) + rnorm(x, sd = 0.2)
m <- svm(x, y)
we can do predict(m,x) to get the fitted values. But what if I wan tho get them by hand?
Seem to me like it should be
w = t(m$coefs)%*%m$SV
x.scaled = scale(x, m$x.scale[[1]], m$x.scale[[2]])
t(w %*% t(as.matrix(x.scaled))) - m$rho but this is wrong
If i
2005 Jun 15
2
need help on computing double summation
Dear helpers in this forum,
This is a clarified version of my previous
questions in this forum. I really need your generous
help on this issue.
> Suppose I have the following data set:
>
> id x y
> 023 1 2
> 023 2 5
> 023 4 6
> 023 5 7
> 412 2 5
> 412 3 4
> 412 4 6
> 412 7 9
> 220 5 7
> 220 4 8
> 220 9 8
> ......
>
Now I want to compute the
2005 Jun 14
1
within and between subject calculation
Dear helpers in this forum,
I have the following question:
Suppose I have the following data set:
id x y
023 1 2
023 2 5
023 4 6
023 5 7
412 2 5
412 3 4
412 4 6
412 7 9
220 5 7
220 4 8
220 9 8
......
and i want to calculate sum_{i=1}^k
sum_{j=1}^{n_i}x_{ij}*y_{ij}
is there a simple way to do this within and between
subject summation in R?
2009 Mar 25
1
Confusion about ecdf
Hi,
I'm bit confused about ecdf (read the help files but still not sure about
this). I have an analytical expression for the pdf, but want to get the
empirical cdf. How do I use this analytical expression with ecdf?
If this helps make it concrete, the pdf is:
f(u) = \sum_{t = 1}^T 1/n_t \sum_{i = 1}^{n_t} 1/w K((u - u_{it})/w)
where K = kernel density estimator, w = weights, and u_{it} =
2008 Mar 27
1
functions
I wrote some functions for multiway CANDECOMP, i.e. for least
squares fitting of
a_{i_1\cdots i_m}\approx\sum_{s=1}^p x^1_{i_1s}x^1_{i_1s}\cdots
x^m_{i_ms}
with arrays of arbitrary dimension. Reminded me of the good old APL
days. I could not find this in the archives, but if it's already there,
I would appreciate if someone let me know.