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uBLAS - Calculation of Inverse and/or Least Squares
by jonny5cents <jon_nichols95＠hotmail.com> 07 Jan '03

07 Jan '03

Hello All, Can anyone suggest the best way to use uBLAS to calculate the inverse of a matrix?? One of the reasons I want to do this is to solve a linear least squares problem, which I know can be done without explicitly solving for the inverse. Does anyone know if this is possible?? thanks, jon

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ublas - newbie question and comment
by Mike Hayford 07 Jan '03

07 Jan '03

I discovered uBLAS a week ago and am very impressed by the design and implementation of the library. To learn the library I have been porting a few non-linear least squares codes from FORTRAN into uBLAS. A real hinderance is the documentation. There is no user's guide or set of example code to orient the new user to uBLAS. Some of the most valuable features are undocumented - such as scalar_vector, vector_indirect, and matrix_indirect. The widespread adoption of uBLAS by the C++ numeric community would be more rapid if these omissions were addressed. I would be willing to write up some of the *simple* examples I have done, if people think it would be useful. If my implementations can be improved, that would be even better. I'm new to Boost and haven't yet completely RTFM'd the requirements for Boost doc contributions so point me in the right direction if I'm going astray here. Having said that, I have a specific problem I'm trying to solve. I'm looking for the best "uBLAS-style" solution - I can do an element-by-element brute force solution. Problem: write the product of a diagonal matrix and a vector when the diagonal matrix is stored as a vector. So what I want to do figuratively is: int n = 5; vector<double> x(n), y(n), diag(n); diagonal_matrix<double> dMat(n); dMat = diag; x = prod(dMat, y); Is there a matrix adaptor of some sort that can fill the role of diagonal_matrix<> above? I looked in the header files and didn't see anything obvious. Thanks in adavance for your help. Mike Hayford --------------------------------- Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now [Non-text portions of this message have been removed]

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[date_time] error C2782: _STL::abs() : template parameter 'T' is ambiguous
by Nick Toze <geeky_nick＠yahoo.co.uk> 06 Jan '03

06 Jan '03

Hello, Seems a bit similar to an earlier post, but this is using msvc6. The ambiguity is with "stlport\stl\_complex.h" (version 4.5.3). The error is: d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(33) : error C2782: ' __cdecl _STL::abs()' : template parameter 'T' is ambiguous could be 'long double' or 'const struct _STL::complex<long double> &' d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(33) : error C2785: ' __cdecl _STL::abs()' and 'long double __cdecl _STL::abs(const struct _STL::complex<long double> &)' have different return types d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(30) : see declaration of 'abs' d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(33) : error C2782: ' __cdecl _STL::abs()' : template parameter 'T' is ambiguous could be 'double' or 'const struct _STL::complex<double> &' d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(33) : error C2785: ' __cdecl _STL::abs()' and 'double __cdecl _STL::abs(const struct _STL::complex<double> &)' have different return types d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(30) : see declaration of 'abs' d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(33) : error C2782: ' __cdecl _STL::abs()' : template parameter 'T' is ambiguous could be 'float' or 'const struct _STL::complex<float> &' d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(33) : error C2785: ' __cdecl _STL::abs()' and 'float __cdecl _STL::abs(const struct _STL::complex<float> &)' have different return types d:\c_plus_plus\boost_1_29_0\boost\date_time\compiler_config.hpp(30) : see declaration of 'abs'

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error C2668: 'abs' : ambiguous call to overloaded function
by Black Ice 06 Jan '03

06 Jan '03

boost version 2002-01-02 VC 7.1 Final Beta "error C2668: 'abs' : ambiguous call to overloaded function" when compile following code. The same code can be built successfully in vc6. Any suggestion are appreciated. #define DATE_TIME_INLINE #define BOOST_DATE_TIME_POSIX_TIME_STD_CONFIG #include <iostream> #include <string> using namespace std; #include <boost/date_time/gregorian/gregorian.hpp> #include <boost/date_time/posix_time/posix_time.hpp> using namespace boost::gregorian; using namespace boost::posix_time; void testDateTime2() { date d(2002, Nov, 1); //an arbitrary date ptime t1(d, hours(5) + nanosec(100));//date + time of day offset ptime t2 = t1 - minutes(4)+seconds(2); ptime now = second_clock::local_time(); //use the clock //Get the date part out of the time date today = now.date(); date tommorrow = today + date_duration(1); ptime tommorrow_start(tommorrow); //midnight cout << "d is " << to_iso_extended_string(d) << endl; cout << "t1 is " << to_iso_extended_string(t1) << endl; cout << "t2 is " << to_iso_extended_string(t2) << endl; cout << "now is " << to_iso_extended_string(now) << endl; cout << "today is " << to_iso_extended_string(today) << endl; cout << "tommorrow is " << to_iso_extended_string(tommorrow) << endl; cout << "tommorrow_start is " << to_iso_extended_string(tommorrow_start) << endl; //starting at current time iterator adds by one hour time_iterator titr(now,hours(1)); for (; titr < tommorrow_start; ++titr) { cout << to_iso_extended_string(*titr) << endl; } } -- /*******************/ ×ÔÓÉ£šliberty£©ÎÞ·ÇŸÍÊÇÕâÑùÒ»ÖÖ³ÐÅµ£ºÃ¿žöÈËœ«»áµÃµœÒ»ÖÖ±£ÕÏ£¬±£ÕÏÎÒÃÇ¿ÉÒÔÓë ÈšÍþ¡¢¶àÊý¡¢Á÷Ë×Œ°ÓßÂÛµÄÓ°ÏìÏà¿¹ºâ¡£ /*******************/

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RE: [Boost-Users] Re: error C2668: 'abs' : ambiguous call to overloaded function
by Jeff Garland 06 Jan '03

06 Jan '03

> After I move the line 'using std namespace', the error still occurs. > The error occurs in file date_time/time_duration.hpp, line 66. > min_type minutes() const > { > return std::abs(((ticks() / (60*rep_type::res_adjust())) % 60)); > } > It seems like the abs function declared in boost/date_time/compiler_config. hpp will not be included due to the macro configuration. The relavant code snippet is: //boost/date_time/compiler_config.hpp //Work around compilers that don't have std::abs #if (__GNUC__ <= 3)|| (defined(BOOST_MSVC) && _MSC_VER <= 1200) # define BOOST_NO_LONG_LONG_ABS #endif #if defined(BOOST_NO_LONG_LONG_ABS) namespace std { template <typename T> // JDG [7/6/02 made a template] inline T abs(T x) { return x < 0 ? -x : x; } } #endif You might try altering this so that the function will be defined. Something like (line 22) #if (__GNUC__ <= 3)|| defined(BOOST_MSVC) should do the trick. The only thing is that past testing with newer versions of MSVC did not require this so I'm a bit suprised that this is needed. This will only work if the problem is that the compiler is trying to convert the underlying type boost::int64_t into a long or another type because it lacks a std::abs for this type. Jeff

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Re: [Boost-Users] Re: error C2668: 'abs' : ambiguous call to overloade
by martynl＠cix.compulink.co.uk 06 Jan '03

06 Jan '03

In-Reply-To: <av5tpc$fmj$1(a)main.gmane.org> Black Ice, > After I move the line 'using std namespace', the error still occurs. > The error occurs in file date_time/time_duration.hpp, line 66. > min_type minutes() const > { > return std::abs(((ticks() / (60*rep_type::res_adjust())) % 60)); > } For VC++ 7.1, we've enabled by default conformant overloads of abs that were previously disabled by default. As a result, you'll need to cast the result of your math to a specific type to ensure you get the abs you want. Martyn Lovell Software Architect Visual C++ Team - Libraries email: lnytram(a)tfosorcim.moc [Spam-avoidance: reverse each word in the email address before use] This posting is provided "AS IS" with no warranties, and confers no rights.

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Compile error when build boost with vc 7 and vc 7.1
by Black Ice 04 Jan '03

04 Jan '03

The last version of boost has got by CVS. set BOOST_ROOT=d:\boost\boost set VC7_ROOT=D:\Program Files\Microsoft Visual Studio .NET 2003\Vc7 bjam "-sTOOLS=vc7" Command line error D2016 : '/Za' and '/Ze' command-line options are incompatible -- /*******************/ ×ÔÓÉ£šliberty£©ÎÞ·ÇŸÍÊÇÕâÑùÒ»ÖÖ³ÐÅµ£ºÃ¿žöÈËœ«»áµÃµœÒ»ÖÖ±£ÕÏ£¬±£ÕÏÎÒÃÇ¿ÉÒÔÓë ÈšÍþ¡¢¶àÊý¡¢Á÷Ë×Œ°ÓßÂÛµÄÓ°ÏìÏà¿¹ºâ¡£ /*******************/

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auto_array?
by Duane Murphy 04 Jan '03

04 Jan '03

Is there a class filling in the missing piece to the memory management puzzle for an auto_array? We have: scoped_ptr and scoped_array, shared_ptr and shared_arry, and auto_ptr. I would like to have an auto_array. Basically the feature that is missing is to create an array, initialize it and then transfer ownership as a way of managing exceptions during the initialization phase. For the time being I am using a shared_array. Thank for any suggestions. ...Duane

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Re: [Boost-Users] Re: Re: Re: Slight Alteration to Boost Directory Structure
by William E. Kempf 04 Jan '03

04 Jan '03

> From: "Paul Mensonides" <yg-boost-users(a)m.gmane.org> > "William E. Kempf" <wekempf(a)cox.net> wrote in message > news:20030108174453.YIAW22825.lakemtao04.cox.net@smtp.east.cox.net... > > > > That is not what he (or I) means. He is suggesting that the path to > > > "shared_ptr.hpp" should be "$INCLUDE/boost/shared_ptr.hpp" rather than > > > "$INCLUDE/boost/boost/shared_ptr.hpp", which is the way it is now. > > > Everything would still be the same for including headers except that > only a > > > single search path is necessary to setup with the compiler. > > > > That's the way it is now *only* if you set your include directories > incorrectly. When they are properly set to $BOOST_ROOT then it's only > <boost/shared_ptr.hpp>, not <boost/boost/shared_ptr.hpp>. > > ...which is precisely the point. You have to have a separate include > directory for Boost, rather than a single directory which contains various > libraries. I.e. it would be nice to have a directory structure like this: > > $INCLUDE/ > Loki/*.* > Boost/*.* > > And then have only a single header directory: $INCLUDE. I'm not talking > about the paths in the source code (i.e. <boost/shared_ptr.hpp>); I'm > talking about the include directories that the compiler searches, which is > external to the source code. That still misses the point. Boost currently won't help you to install the library, but installation certainly wouldn't entail copying the entire $BOOST_ROOT tree to the $INCLUDE directory on your system. You'd only copy the $BOOST_ROOT/boost tree there. William E. Kempf wekempf(a)cox.net

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RegEx: (?= ) and (?! )
by Yutaka Emura <yutaka＠emurasoft.com> 02 Jan '03

02 Jan '03

Hi, I am using RegEx in Boost v1.29.0. (?= ) and (?! ) expressions do not seem to work at a certain condition. In the following example, "(?=a)b" should match "b" in "xyzabcdefg", but does not. Similarly, "(?!a)b" should not match "b" in "xyzabcdefg" but it does. Can please let me know what is wrong? Thank you for your reply in advance. Yutaka Emura --------- boost::regex expression; boost::match_results<std::string::const_iterator> subexp; expression.assign("(?=a)b", boost::regbase::perl); if (boost::regex_search((std::string::const_iterator)"xyzabcdefg", (std::string::const_iterator)"xyzabcdefg" + 10, subexp, expression, boost::match_default)) { { // should go here } else { // goes here } expression.assign("(!=a)b", boost::regbase::perl); if (boost::regex_search((std::string::const_iterator)"xyzabcdefg", (std::string::const_iterator)"xyzabcdefg" + 10, subexp, expression, boost::match_default)) { { // goes here } else { // should go here }

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