3. Matrix Klasse mit Vectoren

Matrix Klasse mit Vectoren

  • K

    Ein Hinweis nebenbei: der Container std::valarray könnte sich für numerische Operationen besser eignen als std::vector.

    Gruß Kimmi

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  • B

    Habe ein ähnliches Problem.
    Würde sich valarray auch bei großen Datentypen, wie z.B. aus gmp, auch besser eignen?
    Was hätte eine bessere Preformance?

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  • B
     

    Matrix(int d1, int d2) : mat(d1, std::vector<int>(d2)){}
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  • Welche Vorteile hat in diesem Fall ( Matrizen sind meistens von konstanter Länge ) eigentlich die Verwendung von std::vector?

    früher gabs da mal so dinge wie new und delete...

    *sich auf den Kritik-hagel vorbereitet*

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  • B

    leider funktioniert mit gmp (mpq_t) das nicht:

    Matrix(int d1, int d2) : mat(d1, std::vector<mpq_t>(d2)){}

    wahrscheinlich muss ich sowas wie laraM vorgeschlagen hat machen:

    vector<mpq_t*> mat

    machen.

    und dann auch über new und delete gehen oder?
    Hat einer sowas schonmal gemacht?

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  • B

    Was funktioniert nicht?

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  • B
     

    Matrix(int d1, int d2) : mat(d1, std::vector<mpq_t>(d2)){}

    ‘std::vector<_Tp, _Alloc>::vector(size_t, const _Tp&, const _Alloc&) [with _Tp = __mpq_struct [1], _Alloc = std::allocator<__mpq_struct [1]>]’:

 error: conversion from ‘int’ to non-scalar type ‘__mpq_struct [1]’ requested
/usr/include/c++/4.3/bits/stl_construct.h: In function ‘void std::_Destroy(_Tp*) [with _Tp = __mpq_struct [1]]’:
/usr/include/c++/4.3/bits/stl_construct.h:103:   instantiated from ‘void std::_Destroy(_ForwardIterator, _ForwardIterator) [with _ForwardIterator = __mpq_struct (*)[1]]’
/usr/include/c++/4.3/bits/stl_construct.h:128:   instantiated from ‘void std::_Destroy(_ForwardIterator, _ForwardIterator, std::allocator<_T2>&) [with _ForwardIterator = __mpq_struct (*)[1], _Tp = __mpq_struct [1]]’
/usr/include/c++/4.3/bits/stl_vector.h:300:   instantiated from ‘std::vector<_Tp, _Alloc>::~vector() [with _Tp = __mpq_struct [1], _Alloc = std::allocator<__mpq_struct [1]>]’

    ich denke das hat was damit zu tun, das ich den ersten vector erst mit mpq_init() aufrufen müßte, bevor ich zweite Dimension einfügen kann, oder?

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  • L

    Kann es sein dass die Membervariable "mat" noch vom Typ vector<vector<int> > ist?

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  • B
     

    class Matrix {
public:
	Matrix();
	Matrix(int rows, int cols): mat(rows, vector<mpq_t>(cols)){};

private:
	vector< vector<mpq_t> > mat;

};

    hmm

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  • B

    Es klappt auch schon eindimensional nicht:

    class Matrix {
public:
	Matrix();
	Matrix(int rows): mat(rows){};
private:
	vector<mpq_t > mat;

};

    selbe Fehlermeldung:

    ../Matrix.h: In constructor ‘std::vector<_Tp, _Alloc>::vector(size_t, const _Tp&, const _Alloc&) [with _Tp = __mpq_struct [1], _Alloc = std::allocator<__mpq_struct [1]>]’:
../Matrix.h:20: error: conversion from ‘int’ to non-scalar type ‘__mpq_struct [1]’ requested
/usr/include/c++/4.3/bits/stl_construct.h: In function ‘void std::_Destroy(_Tp*) [with _Tp = __mpq_struct [1]]’:
/usr/include/c++/4.3/bits/stl_construct.h:103:   instantiated from ‘void std::_Destroy(_ForwardIterator, _ForwardIterator) [with _ForwardIterator = __mpq_struct (*)[1]]’
/usr/include/c++/4.3/bits/stl_construct.h:128:   instantiated from ‘void std::_Destroy(_ForwardIterator, _ForwardIterator, std::allocator<_T2>&) [with _ForwardIterator = __mpq_struct (*)[1], _Tp = __mpq_struct [1]]’
/usr/include/c++/4.3/bits/stl_vector.h:300:   instantiated from ‘std::vector<_Tp, _Alloc>::~vector() [with _Tp = __mpq_struct [1], _Alloc = std::allocator<__mpq_struct [1]>]’
../Matrix.h:20:   instantiated from here
/usr/include/c++/4.3/bits/stl_construct.h:88: error: request for member ‘~__mpq_struct [1]’ in ‘* __pointer’, which is of non-class type ‘__mpq_struct [1]’
/usr/include/c++/4.3/bits/stl_algobase.h: In function ‘typename __gnu_cxx::__enable_if<(! std::__is_scalar::__value), _OutputIterator>::__type std::__fill_n_a(_OutputIterator, _Size, const _Tp&) [with _OutputIterator = __mpq_struct (*)[1], _Size = unsigned int, _Tp = __mpq_struct [1]]’:
/usr/include/c++/4.3/bits/stl_algobase.h:784:   instantiated from ‘_OI std::fill_n(_OI, _Size, const _Tp&) [with _OI = __mpq_struct (*)[1], _Size = unsigned int, _Tp = __mpq_struct [1]]’
/usr/include/c++/4.3/bits/stl_uninitialized.h:209:   instantiated from ‘static void std::__uninitialized_fill_n<true>::uninitialized_fill_n(_ForwardIterator, _Size, const _Tp&) [with _ForwardIterator = __mpq_struct (*)[1], _Size = unsigned int, _Tp = __mpq_struct [1]]’
/usr/include/c++/4.3/bits/stl_uninitialized.h:228:   instantiated from ‘void std::uninitialized_fill_n(_ForwardIterator, _Size, const _Tp&) [with _ForwardIterator = __mpq_struct (*)[1], _Size = unsigned int, _Tp = __mpq_struct [1]]’
/usr/include/c++/4.3/bits/stl_uninitialized.h:323:   instantiated from ‘void std::__uninitialized_fill_n_a(_ForwardIterator, _Size, const _Tp&, std::allocator<_Tp2>&) [with _ForwardIterator = __mpq_struct (*)[1], _Size = unsigned int, _Tp = __mpq_struct [1], _Tp2 = __mpq_struct [1]]’
/usr/include/c++/4.3/bits/stl_vector.h:976:   instantiated from ‘void std::vector<_Tp, _Alloc>::_M_fill_initialize(size_t, const _Tp&) [with _Tp = __mpq_struct [1], _Alloc = std::allocator<__mpq_struct [1]>]’
/usr/include/c++/4.3/bits/stl_vector.h:236:   instantiated from ‘std::vector<_Tp, _Alloc>::vector(size_t, const _Tp&, const _Alloc&) [with _Tp = __mpq_struct [1], _Alloc = std::allocator<__mpq_struct [1]>]’
../Matrix.h:20:   instantiated from here
/usr/include/c++/4.3/bits/stl_algobase.h:741: error: invalid array assignment

    schade.. kennt einer einen ausweg

    (sorry LaraM, hätte einen eigenen Beitrag aufmachen sollen 😞 )

    EDIT: Ich habe einen eigenen Beitrag aufgemacht!

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