As a long time user of Subversion, I’ve got used to use of svn info command. Since I started drifting to Git system, I’ve missed this command pretty much until I found git-info script crafted by Duane Johnson
Kudos to Duane! And, I suggest any SVN user who reincarnated as Git user to grab and try it.
I’ve started to experiment with the Intel Threading Building Blocks and hit a wall trying to run a very simple example:
#include <tbb/parallel_sort.h>
#include <cmath>
#include <vector>
using namespace tbb;
int main()
{
const int n = 100000;
std::vector<double> a(n);
for (int i = 0; i< n; i++)
{
a[i] = std::sin(double(i));
}
parallel_sort(a.begin(), a.end());
}$ g++ -O0 -g -DTBB_USE_DEBUG -o sort_vector sort_vector.cpp -ltbb $ gdb ./sort_vector (gdb) run Starting program: /home/mloskot/workshop/tbb/parallel_sort/sort_vector [Thread debugging using libthread_db enabled] Program received signal SIGSEGV, Segmentation fault. tbb::task_group_context::init (this=0x7ffffff9c4e0) at ../../src/tbb/task.cpp:3124 3124 ../../src/tbb/task.cpp: No such file or directory. in ../../src/tbb/task.cpp (gdb) bt #0 tbb::task_group_context::init (this=0x7ffffff9c4e0) at ../../src/tbb/task.cpp:3124 #1 0x00000000004013ff in task_group_context (this=0x7ffffff9c4e0, relation_with_parent=tbb::task_group_context::bound) at /usr/include/tbb/task.h:284 #2 0x0000000000401be4 in tbb::internal::parallel_quick_sort> (begin=0x7ffffff9c6a0, end=0x7fffffffe120, comp=...) at /usr/include/tbb/parallel_sort.h:155 #3 0x0000000000401b23 in tbb::parallel_sort > (begin=0x7ffffff9c6a0, end=0x7fffffffe120, comp=...) at /usr/include/tbb/parallel_sort.h:203 #4 0x0000000000401ab3 in tbb::parallel_sort (begin=0x7ffffff9c6a0, end=0x7fffffffe120) at /usr/include/tbb/parallel_sort.h:219 #5 0x0000000000401363 in main () at sort_vector.cpp:12
It seems like a failure during initialization of worker threads pool or close to it.
I’m using fairly recent version of TBB 2.1 installed from Ubuntu 9.10 packages, but I’m suspicious this may be a problem with this particular binary version. Let’s see what Intel folks will judge parallel_sort example throws segmentation fault. Pity Microsoft PPL does not provide parallel_sort algorithm.
Update: see parallel_sort problem fixed
Activity of the OSGeo Community quite heavily relies on the Freenode IRC network, so this may be an interesting news:
hackers are exploiting a weakness in the Mozilla Firefox browser to wreak havoc on Freenode and other networks that cater to users of internet relay chat.
Here is the whole story Firefox-based attack wreaks havoc on IRC users posted to The Register
Mr Dan Goodin, I would wish you don’t cultivate the mainstream media alignment regarding the use of word hacker. Don’t call a hacker someone who has unlawful intentions, please.
A few minutes ago, Bill Hoffman from Kitware posted short message to the CMake project mailing list with an interesting announce:
Kitware launched its first developer blog today with contributions from Company technical and business leaders.
The CMake build system is one of the main category of topics on the Kitware blog, so I presume it may be of interest of OSGeo Community as the CMake build system is slowly winning over more and more folks here :-)
First CMake-related post is about Deploying on Windows with DLL Manifest Issue
Another interesting post on the blog is Will Schroeder’s answer to the question Why Open Source Will Rule Scientific Computing? It’s really worth reading.
One of possible and reasonable answers given at gitvsmercurial.com
It’s an example of b***dy quick attempt to configure CMake-based build of a fairly large library written in C++ programming language. It is GEOS.
Seven. A lucky number. Arnulf’s nickname. Total number of lines (commands) of CMake script to configure build of GEOS C++ core as a static library using sources form SVN trunk:
Create trunk/CMakeLists.txt file:
project(geos)
cmake_minimum_required(VERSION 2.6)
set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
add_subdirectory(src)
Create trunk/src/CMakeLists.txt file:
include_directories(${CMAKE_SOURCE_DIR}/include)
file(GLOB_RECURSE geos_SRC ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp)
add_library(geos STATIC ${geos_SRC})
In fact, only six lines are really required. The third line in file trunk/CMakeLists.txt is optional.
mloskot@dog:~/dev/geos/_svn/trunk$ svn status ? CMakeLists.txt ? src/CMakeLists.txt mloskot@dog:~/dev/geos/_svn/trunk$ mkdir ../build mloskot@dog:~/dev/geos/_svn/trunk$ cd ../build/ mloskot@dog:~/dev/geos/_svn/build$ cmake ../trunk -- The C compiler identification is GNU -- The CXX compiler identification is GNU -- Check for working C compiler: /usr/bin/gcc -- Check for working C compiler: /usr/bin/gcc -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working CXX compiler: /usr/bin/c++ -- Check for working CXX compiler: /usr/bin/c++ -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Configuring done -- Generating done -- Build files have been written to: /home/mloskot/dev/geos/_svn/build mloskot@dog:~/dev/geos/_svn/build$ mloskot@dog:~/dev/geos/_svn/build$ make -j5 Scanning dependencies of target geos [ 0%] Building CXX object src/CMakeFiles/geos_lib.dir/operation/valid/RepeatedPointTester.cpp.o ...
and 53 seconds later my Intel Core 2 Duo 2.4GHz box announces:
[100%] Building CXX object src/CMakeFiles/geos.dir/linearref/LengthIndexOfPoint.cpp.o Linking CXX static library libgeos.a [100%] Built target geos
This build configuration is universal and cross platform, thus should work on all platforms supported by CMake.
Simply, you can not afford not use the best cross-platform build system that ever existed :-)
Bill Hoffman from Kitware gives presentation about CMake and a pack of related tools to the happiest easygoing working nation on the Earth:
It’s worth to watch if interested in CMake.
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