Hello Francesc,
The problem appears to related to my lack of optimization in the
compilation. If I use
gcc -O3 -c my_lib.c -fPIC -fopenmp -ffast-math
the C executable and ctypes/python versions behave almost identically.
Getting decent behavior takes some thought, though, far from the
incredi
Sebastian,
Optimization appears to be important here. I used no optimization in my
previous post, so you could try the -O3 compile option:
gcc -O3 -c my_lib.c -fPIC -fopenmp -ffast-math
for na=329 and nb=340 I get (about 7.5 speedup)
c_threads 1 time 0.00103106021881
c_threads 2 time 0.000
A Saturday 12 February 2011 21:19:39 Eric Carlson escrigué:
> Hello All,
> I have been toying with OpenMP through f2py and ctypes. On the whole,
> the results of my efforts have been very encouraging. That said, some
> results are a bit perplexing.
>
> I have written identical routines that I run
Update:
I just noticed that using Eric's OpenMP code gave me only a 1.35x
speedup when comparing 3 threads vs. my non OpenMP code. However, when
comparing 3 threads vs. 1 thread, I could call this a 2.55x speedup.
This obviously sounds much better, but is obviously not the number
that matters...
(E
Hi,
Thanks for the two solutions.
Indeed, there are much faster than the brute force method using in.
The setmember1d is deprecate din newer python releases, therefore I already
switched to in1d().
(Thanks Josef.)
Andreas
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Eric,
this is amazing !! Thanks very much, I have rarely seen such a compact
source example that just worked.
The timings I get are:
c_threads 1 time 0.00155731916428
c_threads 2 time 0.000829789638519
c_threads 3 time 0.00061688839
c_threads 4 time 0.000704760551453
c_threads 5 t
I want to use unwrap to process a sequence of segments, such that the sequence
appears continous. That is, unwrap maintains a state which represents a
multiple of 2\pi. I want to continue that state with the next call to unwrap.
Or in other words, I'd like to specify an initial phase for the st
Matthieu,
I got it to run in valgrind (using the options from your blog).
For dist2d() it says under "Types":
--
Event Type Incl.SelfShort Formula
-
Found a solution myself:
I tried to compile the fib1.f file directly using the gfortran compiler, and
found that indentation in the (fixed format) file was wrong. Correcting this
took care of the "target file xxx not generated" error, but still an error
resulted:
...
...
error: Unable to find vcv
Hi all,
I'm glad to inform you about new, 4th OpenOpt Suite module:
SpaceFuncs - a tool for 2D, 3D, N-dimensional geometric modeling with
possibilities of parametrized calculations, numerical optimization and
solving systems of geometrical equations with automatic
differentiation.
Chris,
OK, sorry -- I miss read (cdist doc says A and B must have same number
of "columns"(!) not "rows").
On my machine I got the exact same timing as my (non OpenMP) C code.
That is really got, compared to normal ufunc based numpy code.
But my question in this thread is, how to get better than th
On 16/feb/2011, at 00:04, numpy-discussion-requ...@scipy.org wrote:
>
> I'm sorry that I don't have some example code for you, but you
> probably need to break down the problem if you can't fit it into
> memory: http://en.wikipedia.org/wiki/Overlap-add_method
>
> Jonathan
Thanks! You saved my
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