- Boost-users - lists.preview.boost.org

Ublas >> operators
by Amit Bhatia 08 Jul '03

08 Jul '03

Hello All, I was looking for sowe way to write the matrix to some filestream and read the same way from some file stream. Was just wondering if Ublas has any operators as << and >> defined default? I have been able to find none though. thanks, regards, amit.

2 1

Re: Using BOOST_REQUIRE outside the Test framework?
by Gennadiy E. Rozental 08 Jul '03

08 Jul '03

> Is there some macro/facility/whatever which behaves like assert(): > a) works without the Boost Test Framework > b) *AND* integrates into the BTF in those cases where the BTF is used? > > Regards, > > Joaquín M López Muñoz > Telefónica, Investigación y Desarrollo Jonh Torio developing SMART_ASSERT facility that supposed to satisfy your requirements. Look into main list archive. Gennadiy.

1 0

boost_1_30_0: cannot compile red hat gcc
by sebMarc 07 Jul '03

07 Jul '03

I must be freakin stupid. I have the simplest config possible, gcc 2.96 with a red hat system. Downloaded boot1_30_0, unzipped it, tried to compile thread and got: bash-2.05a$ bjam "-sTOOLS=gcc" ...found 341 targets... ...updating 37 targets... MkDir1 ../../../libs/thread/build/bin-stage : command not found MkDir1 ../../../libs/thread/build/bin : command not found mkdir: cannot create directory `\r': File exists mkdir ../../../libs/thread/build/bin ...failed MkDir1 ../../../libs/thread/build/bin... Being jam ignorant, this is it, i am stuck :-(. Sigh.. Tried to run configure and got: bash-2.05a$ chmod +x configure bash-2.05a$ ./configure : bad interpreter: No such file or directory Seb.

3 3

Memory leaks in Solaris
by Lev Assinovsky 07 Jul '03

07 Jul '03

Hi All! I caught a memory leak (24 bytes) when using recursive_mutex class. This class initializes a pthread_mutexattr attribute but never destroys it thus leaving the leak. We use tons of the recursive mutexes in our huge app and that leak leads to significant memory loss. Regards, Lev Assinovsky Aelita Software Corporation O&S Core Division, Programmer ICQ# 165072909

1 0

Using BOOST_REQUIRE outside the Test framework?
by Joaquín Mª López Muñoz 07 Jul '03

07 Jul '03

I'm deploying a library which implements some basic invariant checking when a certain control macro is defined. class A { void foo1(){VERIFY(*invariant conditions *); ...} ... void foon(){VERIFY(*invariant conditions *); ...} }; I use the word VERIFY for reference purposes only. Now, VERIFY is resolved to a call to assert(), which is sensible enough as: * Invariant errors are critical * Invariant checking is only enabled explictly by the user, presumably under testing conditions. On a second thought, it'd be nice if VERIFY could be seamlessly integrated into the Boost Test Framework, i.e. invariant errors are caught by the test execution monitor as other errors defined by BOOST_CHECK, BOOST_REQUIRE etc. Unfortunately, replacing VERIFY with say BOOST_REQUIRE forces the user to link with the Boost Test Framewok object modules. So my question is: Is there some macro/facility/whatever which behaves like assert(): a) works without the Boost Test Framework b) *AND* integrates into the BTF in those cases where the BTF is used? Regards, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

1 0

multi_array performance
by Marco Segurini 07 Jul '03

07 Jul '03

Hi, I am very new in using Boost library. I start replacing row memory array with 'multi_array' class template but the performace slow down a lot. Running this test program... //begin------------------ #include "windows.h" #include <iostream> #include "boost\multi_array.hpp" using namespace std; using namespace boost; int main() { const size_t DimX = 2000; const size_t DimY = 1500; const size_t DimZ = 1; multi_array<int,3> V3(extents[DimZ][DimY][DimX]); int iVal; unsigned long time1 = GetTickCount(); for (size_t Z=0; Z<DimZ; ++Z) for (size_t Y=0; Y<DimY; ++Y) for (size_t X=0; X<DimX; ++X) iVal = V3[Z][Y][X]; unsigned long time2 = GetTickCount(); cout << "Multi_array: " << time2-time1 << endl; int * pInt = V3.data(); time1 = GetTickCount(); for (size_t Z=0; Z<DimZ; ++Z) for (size_t Y=0; Y<DimY; ++Y) for (size_t X=0; X<DimX; ++X) iVal = pInt[(Z*DimY+Y)*DimX+X]; time2 = GetTickCount(); cout << "Pointer....: " << time2-time1 << endl; return 0; } //end------------------ ... the output (using vc++ in release mode with no optimization) is Multi_array: 1663 Pointer....:70 So, where am I wrong? Thanks. Marco.

6 6

[BGL] dijkstra_shortest_paths and the single-pair problem
by Richard Jepps 04 Jul '03

04 Jul '03

I would like to use the dijkstra_shortest_paths algorithm to find the shortest path from one specified vertex to another. The standard Boost implementation will find this, but it will continue until it has found the shortest paths to all nodes in the graph (i.e. solved the single source problem). The BGL book (Section 5.1, pp76) says: "It turns out that there are no algorithms for solving the single-pair problem that are asymptotically faster than the algorithms that solve the single-source problem". I think this is because the single-source algorithms all have the property that it is possible to determine whether the shortest path to any given node has been found during the execution of the algorithm, therefore you can use the same algorithm to solve both types of problem provided that the termination criterion is appropriate to the problem. Consider this problem: "find the shortest path from a source vertex u to a nearby destination vertex v in an infinitely large directed weighted graph G in finite time." The single-source problem can only be solved in infinite time, but the single-pair problem can be solved relatively quickly (because the two vertices are near each other). I think that the termination criterion is quite straightforward using a DijkstraVisitor - it is when vis.finish_vertex(u, g) is called and u == destination_node. Unfortunately I can't see how to stop the algorithm in a reasonable way. An unreasonable solution is to provide a custom graph and turn off all its edges when the termination criterion is met. This is unreasonable because the responsibility for termination belongs to the algorithm, not the data structure - I shouldn't have to modify the data structure to terminate the algorithm. It's also unreasonable because I have to customise both the graph and the algorithm to do something very simple. Is there a better way? Thanks Richard

3 5

function object with lambda
by Matt Hurd 04 Jul '03

04 Jul '03

Not sure how to force a for_each with a lambda to invoke the random function object successively. In the for_each version below get_long is called just once. Not sure how to use var, std_function, bind or something else to overcome this. I'm sure the answer is straight forward... anyone? Regards, Matt. #include <iostream> #include <boost/random.hpp> #include <vector> #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> typedef boost::mt19937 base_generator_type; base_generator_type generator( 100123u ); boost::uniform_int<base_generator_type,long> gen_long(generator,-100,100); using namespace std; using namespace boost::lambda; int main(int argc, char *argv[]) { vector<long> v(10); for_each(v.begin(),v.end(), _1 = gen_long() ); for_each(v.begin(), v.end(), cout << _1 << ' '); cout << "\n"; for( vector<>::iterator i = v.begin(); i != v.end(); ++i ) { *i = gen_long(); } for_each(v.begin(), v.end(), cout << _1 << ' '); cout << "\n"; system("PAUSE"); return 0; }

2 4

Re: [Boost-Users] [BGL] dijkstra_shortest_paths and the single-pair problem
by JOAQUIN LOPEZ MU?Z 03 Jul '03

03 Jul '03

Throw an exception? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo ----- Mensaje Original ----- De: Richard Jepps <yg-boost-users(a)m.gmane.org> Fecha: Martes, Julio 1, 2003 3:00 pm Asunto: [Boost-Users] [BGL] dijkstra_shortest_paths and the single-pair problem > I would like to use the dijkstra_shortest_paths algorithm to find the > shortest path from one specified vertex to another. > > The standard Boost implementation will find this, but it will > continue until > it has found the shortest paths to all nodes in the graph (i.e. > solved the > single source problem). > > The BGL book (Section 5.1, pp76) says: "It turns out that there > are no > algorithms for solving the single-pair problem that are asymptotically > faster than the algorithms that solve the single-source problem". > I think this is because the single-source algorithms all have the > propertythat it is possible to determine whether the shortest path > to any given node > has been found during the execution of the algorithm, therefore > you can use > the same algorithm to solve both types of problem provided that the > termination criterion is appropriate to the problem. > > Consider this problem: "find the shortest path from a source > vertex u to a > nearby destination vertex v in an infinitely large directed > weighted graph G > in finite time." > The single-source problem can only be solved in infinite time, but the > single-pair problem can be solved relatively quickly (because the two > vertices are near each other). > > I think that the termination criterion is quite straightforward > using a > DijkstraVisitor - it is when vis.finish_vertex(u, g) is called and > u == > destination_node. Unfortunately I can't see how to stop the > algorithm in a > reasonable way. > > An unreasonable solution is to provide a custom graph and turn off > all its > edges when the termination criterion is met. > This is unreasonable because the responsibility for termination > belongs to > the algorithm, not the data structure - I shouldn't have to modify > the data > structure to terminate the algorithm. > It's also unreasonable because I have to customise both the graph > and the > algorithm to do something very simple. > > Is there a better way? > > Thanks > > Richard > > > > > > > > ------------------------ Yahoo! Groups Sponsor -------------------- > -~--> > Get A Free Psychic Reading! Your Online Answer To Life's Important > Questions.http://us.click.yahoo.com/Lj3uPC/Me7FAA/ySSFAA/EbFolB/TM > ------------------------------------------------------------------- > --~-> > > Info: <" target="l">http://www.boost.org> > Wiki: <" target="l">http://www.crystalclearsoftware.com/cgi- > bin/boost_wiki/wiki.pl>Unsubscribe: <')" >mailto:boost-users- > unsubscribe(a)yahoogroups.com> > > Your use of Yahoo! Groups is subject to > http://docs.yahoo.com/info/terms/ > > >

5 5

boost::numeric::ublas::map_array support for the complete std::map interface?
by Markus Werle 03 Jul '03

03 Jul '03

Hi! While trying to test boost::numeric::ublas::map_array as replacement for a std::map in my own code, I found that some memfuns like lower_bound and key_comp are missing. I also found that these can be added quite easily, since e.g. lower_bound exists as external function and only needs to be called in an appropriate way. Though the functions mentioned may not be useful in ublas apps, they would help improve the reusability of map_array. Before I start stalking through the code: Are there any plans to add these features already? Or is there somebody who knows the ublas code better than me and can help me avoid breaking existsing code? best regards, Markus -- Build your own Expression Template Library with Daixtrose! Visit http://daixtrose.sourceforge.net/

2 1