Re: Regarding Standalone Program

[Jaroslav Hajek]

On Wed, Jul 30, 2008 at 2:25 PM, Raghavendra K <address@hidden> wrote:
> Hi Jaroslav,
> Yeah I have been coding C and MPI all my life (never done anything regarding
> C++)
> Actually I was trying to use Octave with C and then now trying to use C++.
> I have one last query. I have a matrix A
> Now I want to find the AXAXAXA (i.e A multiplied 100 times byitself).
> How can I do that in Octave when called by a C++ program?
> Generally in the Octave prompt I used to give A^100.
> Is there any multiplication function implemented?

#include <xpow.h> (or octave/xpow.h, depends on configuration, usually
both works)

...

Matrix AXAXAXA = xpow (A, 100);


> Hoping for a reply again.
>
> Will definitely help you if you happen to be on the MPI forums & stuck with
> something :)
>

Thanks ;)

> On Wed, Jul 30, 2008 at 5:05 PM, Jaroslav Hajek <address@hidden> wrote:
>>
>> On Wed, Jul 30, 2008 at 1:28 PM, Raghavendra K <address@hidden>
>> wrote:
>> > Hi,
>> > Thanks for the reply.
>> > I am trying to use only expm function. (If I get that working all my
>> > problems will be resolved).
>> > When I tried using Matrix:expm(T_a);
>> > I got this error
>> >
>> > test.cc:9: error: no matching function for call to
>> > `Matrix::expm(Matrix&)'
>> >
>> > /garl/garl-alpha1/home1/raghu/july1508_matlab/octave/octave-3.0.1/octave/include/octave-3.0.1/octave/dMatrix.h:258:
>> > error: candidates
>> >    are: Matrix Matrix::expm() const
>> >
>> > What does this mean? ... How can I fix it?
>> > Please do throw some light.
>> >
>>
>>
>> Matrix T_a = something;
>> T_a = T_a.expm ();
>>
>> It seems you're not much familiar with C++, right?
>>
>> > On Wed, Jul 30, 2008 at 4:43 PM, Jaroslav Hajek <address@hidden>
>> > wrote:
>> >>
>> >> On Wed, Jul 30, 2008 at 10:11 AM, Raghavendra K
>> >> <address@hidden>
>> >> wrote:
>> >> > Hi,
>> >> >   I am trying to use 2 functions of Octave in my C++ program, they
>> >> > are
>> >> > zeros and expm
>> >> > When I was using MatlabI was able to contact the matlab engine from
>> >> > the
>> >> > C
>> >> > program using this
>> >> > ep = engOpen("/usr/local/Matlab/bin/matlab
>> >> > and then execute any function of matlab like this
>> >> > engEvalString(ep, "T_a = expm(T_a);");
>> >> >
>> >> > Is there any equivalent way of doing this in Octave?
>> >> > If yes can you please provide some pointers as to how to go about it.
>> >> > Thanks a lot for your time.
>> >> >
>> >>
>> >> As David suggested, there's no need to use "zeros" - the Matrix
>> >> constructor will do the trick.
>> >> Similarly, the Matrix::expm () method will give you the matrix
>> >> exponential.
>> >> You *can* evaluate Octave commands from within C++ using eval_string
>> >> (declared in parse.h). However, as David noted, to use the parser
>> >> engine you first need to initialize it, and you'll need to transfer
>> >> the data to and from the symbol table (if you use normal C++
>> >> variables). Unless you need to call an m-file function, there is
>> >> normally a more straightforward way that avoids using the parser.
>> >>
>> >> > On Wed, Jul 30, 2008 at 1:32 PM, David Bateman
>> >> > <address@hidden>
>> >> > wrote:
>> >> >>
>> >> >> Raghavendra K wrote:
>> >> >>>
>> >> >>> Hi,
>> >> >>>  I am trying to call octave functions from C, but getting an error.
>> >> >>> This is the code that I am using
>> >> >>>
>> >> >>>     #include <iostream>
>> >> >>>     #include <octave/oct.h>
>> >> >>>     int
>> >> >>>     main (void)
>> >> >>>     {
>> >> >>>       std::cout << "Hello Octave world!\n";
>> >> >>>       int n = 2;
>> >> >>>       Matrix a_matrix = Matrix (n, n);
>> >> >>>       a_matrix = zeros(n, n);
>> >> >>>       std::cout << a_matrix;
>> >> >>>       return 0;
>> >> >>>     }
>> >> >>>
>> >> >>
>> >> >> Try
>> >> >>
>> >> >> #include <iostream>
>> >> >> #include <octave/oct.h>
>> >> >> int
>> >> >> main (void)
>> >> >> {
>> >> >>  std::cout << "Hello Octave world!\n";
>> >> >>  int n = 2;
>> >> >>  Matrix a_matrix = Matrix (n, n, 0.);
>> >> >>  std::cout << a_matrix;
>> >> >>  return 0;
>> >> >> }
>> >> >>
>> >> >>
>> >> >> instead. You can't call zeros like that but must use the feval
>> >> >> function,
>> >> >> and if you need feval you have to initialize the parser. There are
>> >> >> threads
>> >> >> in the mailing list about this..
>> >> >>
>> >> >> Regards
>> >> >> David
>> >> >>
>> >> >> --
>> >> >> David Bateman
>> >> >>  address@hidden
>> >> >> Motorola Labs - Paris                        +33 1 69 35 48 04 (Ph)
>> >> >> Parc
>> >> >> Les Algorithmes, Commune de St Aubin    +33 6 72 01 06 33 (Mob)
>> >> >> 91193
>> >> >> Gif-Sur-Yvette FRANCE                  +33 1 69 35 77 01 (Fax)
>> >> >> The information contained in this communication has been classified
>> >> >> as:
>> >> >> [x] General Business Information [ ] Motorola Internal Use Only [ ]
>> >> >> Motorola Confidential Proprietary
>> >> >>
>> >> >
>> >> >
>> >> >
>> >> > --
>> >> > Regards,
>> >> > Raghavendra K
>> >> >
>> >> > _______________________________________________
>> >> > Help-octave mailing list
>> >> > address@hidden
>> >> > https://www.cae.wisc.edu/mailman/listinfo/help-octave
>> >> >
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> RNDr. Jaroslav Hajek
>> >> computing expert
>> >> Aeronautical Research and Test Institute (VZLU)
>> >> Prague, Czech Republic
>> >> url: www.highegg.matfyz.cz
>> >
>> >
>> >
>> > --
>> > Regards,
>> > Raghavendra K
>> >
>>
>>
>>
>> --
>> RNDr. Jaroslav Hajek
>> computing expert
>> Aeronautical Research and Test Institute (VZLU)
>> Prague, Czech Republic
>> url: www.highegg.matfyz.cz
>
>
>
> --
> Regards,
> Raghavendra K
>



-- 
RNDr. Jaroslav Hajek
computing expert
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz