Yes.
On Saturday, October 29, 2016 at 7:06:04 PM UTC-4, digxx wrote:
>
> is it possible to somehow 3d plot the following input?
>
> x=array of length n
> y=array of length m
> z=array of size mxn
>
> like it can be done in matlab?
>
I also prefer the "J" one (http://imgh.us/julia-i18n-j.svg). It's more
balanced. The Hindi "ja" in particular fits the circle better and looks
more balanced without the diacritic "uu" (the loopy thing underneath).
Nice job!
John
On Wednesday, October 5, 2016 at 4:35:10 PM UTC-4, Islam
I would do this via QR decomposition. Produce an orthogonal basis for span
v1, ..., vn via QR, then see if v changes when you project onto the space
spanned by the basis. E.g.
V = [v1 v2 ... vn]
(Q,R) = qr(V)
v - Q*(Q'*v)
That last vector will be zero (small) if v is in span v1, ..., vn.
I
Sheehan: Thanks a million! I am due to teach undergraduate Numerical
Methods next fall and have been planning to do it in Julia. I have a
feeling I'm going to be deeply indebted to you for this course material.
John Gibson
Dept Mathematics & Statistics
University of New Hampshire
On Thur
Good point, thanks. I am still getting used to the semantics of
assigning/copying/referencing Julia arrays.
On Friday, December 18, 2015 at 1:13:38 AM UTC-5, Lutfullah Tomak wrote:
>
># timestepping loop
> for n = 0:Nt
>
> Nn1f = copy(Nnf);
>
> Though unrelated to unrolling, here
Yes, thanks!
I also mistakenly used n as the index variable in a pair of nested loops,
but the loop-index scope rules seem to have saved me there.
On Friday, December 18, 2015 at 3:01:02 AM UTC-5, DNF wrote:
>
> Your last line is:
> u = real(ifft(u))
>
> In that case you seem to be throwing
Hi, all. I'm doing a small test case of Julia's speed & code length for
numerical integration of PDEs, in comparison to Matlab, Python, and C++.
The test case is the 1d Kuramoto-Sivashinksy equation on a 1d periodic
domain, using Fourier expansions for spatial discretization and simple
3.0
0.0
-3.0
-2.0
-1.0
which looks perfectly good.
Next is restructuring the FFTW calls to eliminate allocations. When that's
done I'll follow up with timing comparisons between languages and
naive/optimized codes.
thanks again!
John
On Thursday, December 17, 2015 at 4:51:04 PM UT
I'm no Julia expert, but I'm pretty certain this fall under the category
"If you Julia to optimize, put your code in a function."
gibson@timaeus$ ~/packages/julia-0.4.0/bin/julia
_
_ _ _(_)_ | A fresh approach to technical computing
(_) | (_) (_)|
Agreed w Glenn H here. "math being column major" is because the range of a
matrix being the span of its columns, and consequently most linear algebra
algorithms are naturally expressed as operations on the columns of the
matrix, for example QR decomp via Gramm-Schmidt or Householder, LU without
I'll join in here as well. For years I've seen the mess associated with
existing languages like C, C++, and Fortran as a very substantial
impediment to students developing professional-level expertise in
scientific computation, and in fact I've shied away from trying to teach
what I know,
I can't figure out how to enter a few simple things with the latex-based
unicode entry system.
I can get a variable with name $x_t$ by entering x\_t-tab, but when I try
to get an $x_b$ by entering x\_b-tab, it expands to x\_beta.
And I can't figure out how to do multi-character subscripts,
That clears it up. Thank you.
On Thursday, October 22, 2015 at 4:09:57 PM UTC-4, Yichao Yu wrote:
>
> On Thu, Oct 22, 2015 at 3:58 PM, John Gibson <johnf...@gmail.com
> > wrote:
> > I can't figure out how to enter a few simple things with the latex-based
> > unicod
That clears it up. Thank you.
On Thursday, October 22, 2015 at 4:09:57 PM UTC-4, Yichao Yu wrote:
>
> On Thu, Oct 22, 2015 at 3:58 PM, John Gibson <johnf...@gmail.com
> > wrote:
> > I can't figure out how to enter a few simple things with the latex-based
> > unicod
Having a language where you don't worry about types and the compiler
handles optimization is possible in Fortran because it has a dead-simple,
nonextendable set of types. The downside is that you can't do abstraction
in Fortran, and all your code ends up being a long sequence of low-level
I have to take back a couple things. The Julia docs are clearer than I
thought about the BigFloat type: it's fixed-sized but arbitrarily large,
with size resettable by a function call. Second,
julia> eps(BigFloat)
Why are you trying to roll your own sin(x) function? I think you will be
hard pressed to improve on the library sin(x) in either speed or accuracy.
John
On Saturday, October 17, 2015 at 3:38:17 AM UTC-4, Jeffrey Sarnoff wrote:
>
> I had tried to find a clean way to jump into the taylor series
Search for the comment that begins "OK kiddies, time for the pros"
in
http://stackoverflow.com/questions/2284860/how-does-c-compute-sin-and-other-math-functions
John
On Saturday, October 17, 2015 at 9:00:35 AM UTC-4, John Gibson wrote:
>
> Why are you trying to rol
t ~100 sigbits for angles in -2pi..2pi, but too
> slowly.
>
>
> On Saturday, October 17, 2015 at 9:12:38 AM UTC-4, John Gibson wrote:
>
>> Search for the comment that begins "OK kiddies, time for the pros" in
>> http://stackoverflow.com/questions/2284860/how-d
Does it work from the REPL?
On Monday, October 5, 2015 at 10:28:57 PM UTC-4, halim hamadi wrote:
>
>
>
> I have a problem about the plot data on juno using pyplot.
>
> using PyCall
> using PyPlot
> x = linspace(0,2*pi,1000); y = sin(3*x + 4*cos(2*x))
> plot(x, y, color="red", linewidth=2.0,
See https://github.com/stevengj/PyPlot.jl/issues/140 . The problem stems
from name conflicts between the system libraries libopenblas.so and
liblapack.so and the versions of those two libraries that Julia downloads,
compiles, and installs internally.The solution (at least on Linux) is to
find
Also having gatherings at the University of New Hampshire in the Integrated
Applied Math program, so far watching JuliaCon2015 videos for our video
seminar series, and using Julia in my graduate numerical linear algebra
class instead of Matlab. Can I just say, it's freaking fabulous? I am so
I might have jumped the gun here. Not sure if your uuid problem is caused
by the library name conflict. But it's worth trying the preload.
On Saturday, October 3, 2015 at 11:46:36 AM UTC-4, LarryD wrote:
>
> Hi
>
> I started by removing my old version of Julia and deleting the
>
Marius: I think you'd be better off in learning to write fast Julia code if
you presented an straightforward implementation of a classic PDE problem
and asked for help in optimizing that. Maybe 2D heat equation would be a
good place to start. The code you've presented is not really intelligible
Probably it's for something like indexing by Fourier wavenumber. You
represent a real-valued periodic function as a linear combination of
Fourier modes exp(2 pi i k x/L) where k varies from -K to K-1. The primary
representation in data is an array of complex coefficients for those modes.
It
Run df ~. That'll tell you where the file system containing your home
directory is mounted. If it says nfs:/..., it's NFS-mounted.
John
On Wednesday, August 26, 2015 at 11:12:48 AM UTC-4, Chris wrote:
Hello,
I recently got access to a new Linux machine, and I've been trying to run
some
Charles:
Thanks for your response. I understand now that your application is
ecological, but the mathematical nature and the discretization of your
system is still unclear. You might consider a 'lazy' approach, in which you
compute a distance when you need it, rather than computing them all
What do you mean by distances between sites at different resolution maps?
The word resolution suggests that the N x N size of the matrix results
from the discretization of a continuous function into N data points and the
computation of N^2 distances between those data points. If that's the
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