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MultiArrayView< N, T, C > Class Template Reference

Base class for, and view to, vigra::MultiArray. More...

#include <vigra/multi_array.hxx>

List of all members.

Public Types

enum  ActualDimension
typedef const value_typeconst_pointer
typedef const value_typeconst_reference
typedef
vigra::detail::MultiIteratorChooser
< C >::template Traverser
< actual_dimension, T, T const
&, T const * >::type 
const_traverser
typedef MultiArrayShape
< actual_dimension >::type 
difference_type
typedef MultiArrayIndex difference_type_1
typedef MultiArray< N, T > matrix_type
typedef value_typepointer
typedef value_typereference
typedef difference_type size_type
typedef
vigra::detail::MultiIteratorChooser
< C >::template Traverser
< actual_dimension, T, T &, T * >
::type 
traverser
typedef T value_type
typedef MultiArrayView< N, T, C > view_type

Public Member Functions

template<unsigned int M>
MultiArrayView< N-1, T,
typename
vigra::detail::MaybeStrided< M >
::type > 
bind (difference_type_1 d) const
MultiArrayView< N-1, T,
StridedArrayTag
bindAt (difference_type_1 m, difference_type_1 d) const
template<unsigned int M>
MultiArrayView< N-M, T,
StridedArrayTag
bindInner (const TinyVector< MultiArrayIndex, M > &d) const
MultiArrayView< N-1, T,
StridedArrayTag
bindInner (difference_type_1 d) const
template<unsigned int M>
MultiArrayView< N-M, T, C > bindOuter (const TinyVector< MultiArrayIndex, M > &d) const
MultiArrayView< N-1, T, C > bindOuter (difference_type_1 d) const
difference_type_1 coordinateToScanOrderIndex (const difference_type &d) const
template<class U , class CN >
void copy (const MultiArrayView< N, U, CN > &rhs)
void copy (const MultiArrayView &rhs)
pointer data () const
difference_type_1 elementCount () const
bool hasData () const
template<class U >
MultiArrayViewinit (const U &init)
MultiArrayView< N+1, T, C > insertSingletonDimension (difference_type_1 i) const
bool isInside (difference_type const &p) const
 MultiArrayView ()
 MultiArrayView (const difference_type &shape, pointer ptr)
 MultiArrayView (const difference_type &shape, const difference_type &stride, pointer ptr)
NormTraits< MultiArrayView >
::NormType 
norm (int type=2, bool useSquaredNorm=true) const
template<class U , class C1 >
bool operator!= (MultiArrayView< N, U, C1 > const &rhs) const
const_reference operator() (difference_type_1 x, difference_type_1 y, difference_type_1 z, difference_type_1 u, difference_type_1 v) const
reference operator() (difference_type_1 x)
reference operator() (difference_type_1 x, difference_type_1 y)
reference operator() (difference_type_1 x, difference_type_1 y, difference_type_1 z)
reference operator() (difference_type_1 x, difference_type_1 y, difference_type_1 z, difference_type_1 u)
reference operator() (difference_type_1 x, difference_type_1 y, difference_type_1 z, difference_type_1 u, difference_type_1 v)
const_reference operator() (difference_type_1 x) const
const_reference operator() (difference_type_1 x, difference_type_1 y) const
const_reference operator() (difference_type_1 x, difference_type_1 y, difference_type_1 z, difference_type_1 u) const
const_reference operator() (difference_type_1 x, difference_type_1 y, difference_type_1 z) const
template<class U , class C1 >
MultiArrayViewoperator*= (MultiArrayView< N, U, C1 > const &rhs)
MultiArrayViewoperator*= (T const &rhs)
MultiArrayViewoperator+= (T const &rhs)
template<class U , class C1 >
MultiArrayViewoperator+= (MultiArrayView< N, U, C1 > const &rhs)
MultiArrayViewoperator-= (T const &rhs)
template<class U , class C1 >
MultiArrayViewoperator-= (MultiArrayView< N, U, C1 > const &rhs)
template<class U , class C1 >
MultiArrayViewoperator/= (MultiArrayView< N, U, C1 > const &rhs)
MultiArrayViewoperator/= (T const &rhs)
MultiArrayViewoperator= (MultiArrayView const &rhs)
template<class U , class C1 >
MultiArrayViewoperator= (MultiArrayView< N, U, C1 > const &rhs)
template<class U , class C1 >
bool operator== (MultiArrayView< N, U, C1 > const &rhs) const
template<unsigned int M>
MultiArrayView< N-M, T,
StridedArrayTag
operator[] (const TinyVector< MultiArrayIndex, M > &d) const
reference operator[] (difference_type_1 d)
const_reference operator[] (difference_type_1 d) const
const_reference operator[] (const difference_type &d) const
reference operator[] (const difference_type &d)
MultiArrayView< N, T,
StridedArrayTag
permuteDimensions (const difference_type &s) const
MultiArrayView< N, T,
StridedArrayTag
permuteStridesAscending () const
MultiArrayView< N, T,
StridedArrayTag
permuteStridesDescending () const
difference_type scanOrderIndexToCoordinate (difference_type_1 d) const
difference_type_1 shape (difference_type_1 n) const
const difference_typeshape () const
difference_type_1 size () const
difference_type_1 size (difference_type_1 n) const
NormTraits< MultiArrayView >
::SquaredNormType 
squaredNorm () const
difference_type_1 stride (int n) const
const difference_typestride () const
MultiArrayView< N, T,
StridedArrayTag
stridearray (const difference_type &s) const
difference_type strideOrdering () const
MultiArrayView subarray (const difference_type &p, const difference_type &q) const
template<class T2 , class C2 >
void swapData (MultiArrayView< N, T2, C2 > rhs)
void swapData (MultiArrayView rhs)
MultiArrayView< N, T,
StridedArrayTag
transpose () const
traverser traverser_begin ()
const_traverser traverser_begin () const
const_traverser traverser_end () const
traverser traverser_end ()

Static Public Member Functions

static difference_type strideOrdering (difference_type strides)

Protected Attributes

pointer m_ptr
difference_type m_shape
difference_type m_stride

Detailed Description

template<unsigned int N, class T, class C>
class vigra::MultiArrayView< N, T, C >

Base class for, and view to, vigra::MultiArray.

This class implements the interface of both MultiArray and MultiArrayView. By default, MultiArrayViews are tagged as unstrided. If necessary, strided arrays are constructed automatically by calls to a variant of the bind...() function.

If you want to apply an algorithm requiring an image to a MultiArrayView of appropriate (2-dimensional) shape, you can create a vigra::BasicImageView that acts as a wrapper with the necessary interface -- see Wrap aref vigra::MultiArrayView in.

The template parameter are as follows

    N: the array dimension

    T: the type of the array elements

    C: a tag determining whether the array's inner dimension is strided
       or not. An array is unstrided if the array elements occupy consecutive
       memory location, strided if there is an offset in between (e.g.
       when a view is created that skips every other array element).
       The compiler can generate faster code for unstrided arrays.
       Possible values: UnstridedArrayTag (default), StridedArrayTag

#include <vigra/multi_array.hxx>

Namespace: vigra


Member Typedef Documentation

typedef T value_type
typedef const value_type& const_reference
typedef value_type* pointer
typedef const value_type* const_pointer
typedef MultiArrayShape<actual_dimension>::type difference_type
typedef vigra::detail::MultiIteratorChooser< C>::template Traverser<actual_dimension, T, T &, T *>::type traverser
typedef vigra::detail::MultiIteratorChooser< C>::template Traverser<actual_dimension, T, T const &, T const *>::type const_traverser
typedef MultiArrayView<N, T, C> view_type
typedef MultiArray<N, T> matrix_type

Member Enumeration Documentation

the array's actual dimensionality. This ensures that MultiArrayView can also be used for scalars (that is, when N == 0). Calculated as:

            actual_dimension = (N==0) ? 1 : N

Constructor & Destructor Documentation

default constructor: create an invalid view, i.e. hasData() returns false and size() is zero.

MultiArrayView ( const difference_type shape,
pointer  ptr 
)

construct from shape and pointer

MultiArrayView ( const difference_type shape,
const difference_type stride,
pointer  ptr 
)

Construct from shape, strides (offset of a sample to the next) for every dimension, and pointer. (Note that strides are not given in bytes, but in offsets of the respective pointer type.)


Member Function Documentation

MultiArrayView& operator= ( MultiArrayView< N, T, C > const &  rhs)

Assignment. There are 3 cases:

  • When this MultiArrayView does not point to valid data (e.g. after default construction), it becomes a copy of rhs.
  • When the shapes of the two arrays match, the array contents are copied.
  • Otherwise, a PreconditionViolation exception is thrown.
MultiArrayView& operator= ( MultiArrayView< N, U, C1 > const &  rhs)

Assignment of a differently typed MultiArrayView. Fails with PreconditionViolation exception when the shapes do not match.

MultiArrayView& operator+= ( MultiArrayView< N, U, C1 > const &  rhs)

Add-assignment of a compatible MultiArrayView. Fails with PreconditionViolation exception when the shapes do not match.

MultiArrayView& operator-= ( MultiArrayView< N, U, C1 > const &  rhs)

Subtract-assignment of a compatible MultiArrayView. Fails with PreconditionViolation exception when the shapes do not match.

MultiArrayView& operator*= ( MultiArrayView< N, U, C1 > const &  rhs)

Multiply-assignment of a compatible MultiArrayView. Fails with PreconditionViolation exception when the shapes do not match.

MultiArrayView& operator/= ( MultiArrayView< N, U, C1 > const &  rhs)

Divide-assignment of a compatible MultiArrayView. Fails with PreconditionViolation exception when the shapes do not match.

MultiArrayView& operator+= ( T const &  rhs)
MultiArrayView& operator-= ( T const &  rhs)
MultiArrayView& operator*= ( T const &  rhs)
MultiArrayView& operator/= ( T const &  rhs)
reference operator[] ( const difference_type d)

array access.

const_reference operator[] ( const difference_type d) const

array access.

MultiArrayView<N-M, T, StridedArrayTag> operator[] ( const TinyVector< MultiArrayIndex, M > &  d) const

equvalent to bindInner(), when M < N.

reference operator[] ( difference_type_1  d)

array access in scan-order sense. Mostly useful to support standard indexing for 1-dimensional multi-arrays, but works for any N. Use scanOrderIndexToCoordinate() and coordinateToScanOrderIndex() for conversion between indices and coordinates.

const_reference operator[] ( difference_type_1  d) const

array access in scan-order sense. Mostly useful to support standard indexing for 1-dimensional multi-arrays, but works for any N. Use scanOrderIndexToCoordinate() and coordinateToScanOrderIndex() for conversion between indices and coordinates.

difference_type scanOrderIndexToCoordinate ( difference_type_1  d) const

convert scan-order index to coordinate.

difference_type_1 coordinateToScanOrderIndex ( const difference_type d) const

convert coordinate to scan-order index.

reference operator() ( difference_type_1  x)

1D array access. Use only if N == 1.

reference operator() ( difference_type_1  x,
difference_type_1  y 
)

2D array access. Use only if N == 2.

Reimplemented in Matrix< T, ALLOC >, and Matrix< T >.

3D array access. Use only if N == 3.

4D array access. Use only if N == 4.

5D array access. Use only if N == 5.

const_reference operator() ( difference_type_1  x) const

1D const array access. Use only if N == 1.

const_reference operator() ( difference_type_1  x,
difference_type_1  y 
) const

2D const array access. Use only if N == 2.

Reimplemented in Matrix< T, ALLOC >, and Matrix< T >.

3D const array access. Use only if N == 3.

4D const array access. Use only if N == 4.

5D const array access. Use only if N == 5.

MultiArrayView& init ( const U &  init)
void copy ( const MultiArrayView< N, T, C > &  rhs)

Copy the data of the right-hand array (array shapes must match).

void copy ( const MultiArrayView< N, U, CN > &  rhs)

Copy the data of the right-hand array (array shapes must match).

void swapData ( MultiArrayView< N, T, C >  rhs)

swap the data between two MultiArrayView objects.

The shapes of the two array must match.

void swapData ( MultiArrayView< N, T2, C2 >  rhs)

swap the data between two MultiArrayView objects.

The shapes of the two array must match.

MultiArrayView< N-M, T, C > bindOuter ( const TinyVector< MultiArrayIndex, M > &  d) const

bind the M outmost dimensions to certain indices. this reduces the dimensionality of the image to max { 1, N-M }.

Usage:

            // create a 3D array of size 40x30x20
            typedef MultiArray<3, double>::difference_type Shape;
            MultiArray<3, double> array3(Shape(40, 30, 20));

            // get a 1D array by fixing index 1 to 12, and index 2 to 10
            MultiArrayView <1, double> array1 = array3.bindOuter(TinyVector<int, 2>(12, 10));
MultiArrayView< N-M, T, StridedArrayTag > bindInner ( const TinyVector< MultiArrayIndex, M > &  d) const

bind the M innermost dimensions to certain indices. this reduces the dimensionality of the image to max { 1, N-M }.

Usage:

            // create a 3D array of size 40x30x20
            typedef MultiArray<3, double>::difference_type Shape;
            MultiArray<3, double> array3(Shape(40, 30, 20));

            // get a 1D array by fixing index 0 to 12, and index 1 to 10
            MultiArrayView <1, double, StridedArrayTag> array1 = array3.bindInner(TinyVector<int, 2>(12, 10));
MultiArrayView< N-1, T, typename detail::MaybeStrided< M >::type > bind ( difference_type_1  d) const

bind dimension M to index d. this reduces the dimensionality of the image to max { 1, N-1 }.

Usage:

            // create a 3D array of size 40x30x20
            typedef MultiArray<3, double>::difference_type Shape;
            MultiArray<3, double> array3(Shape(40, 30, 20));

            // get a 2D array by fixing index 1 to 12
            MultiArrayView <2, double> array2 = array3.bind<1>(12);

            // get a 2D array by fixing index 0 to 23
            MultiArrayView <2, double, StridedArrayTag> array2a = array3.bind<0>(23);
MultiArrayView< N-1, T, C > bindOuter ( difference_type_1  d) const

bind the outmost dimension to a certain index. this reduces the dimensionality of the image to max { 1, N-1 }.

Usage:

            // create a 3D array of size 40x30x20
            typedef MultiArray<3, double>::difference_type Shape;
            MultiArray<3, double> array3(Shape(40, 30, 20));

            // get a 2D array by fixing the outermost index (i.e. index 2) to 12
            MultiArrayView <2, double> array2 = array3.bindOuter(12);
MultiArrayView< N-1, T, StridedArrayTag > bindInner ( difference_type_1  d) const

bind the innermost dimension to a certain index. this reduces the dimensionality of the image to max { 1, N-1 }.

Usage:

            // create a 3D array of size 40x30x20
            typedef MultiArray<3, double>::difference_type Shape;
            MultiArray<3, double> array3(Shape(40, 30, 20));

            // get a 2D array by fixing the innermost index (i.e. index 0) to 23
            MultiArrayView <2, double, StridedArrayTag> array2 = array3.bindInner(23);
MultiArrayView< N-1, T, StridedArrayTag > bindAt ( difference_type_1  m,
difference_type_1  d 
) const

bind dimension m to index d. this reduces the dimensionality of the image to max { 1, N-1 }.

Usage:

            // create a 3D array of size 40x30x20
            typedef MultiArray<3, double>::difference_type Shape;
            MultiArray<3, double> array3(Shape(40, 30, 20));

            // get a 2D array by fixing index 2 to 15
            MultiArrayView <2, double, StridedArrayTag> array2 = array3.bindAt(2, 15);
MultiArrayView< N+1, T, C > insertSingletonDimension ( difference_type_1  i) const

Add a singleton dimension (dimension of legth 1).

Singleton dimensions don't change the size of the data, but introduce a new index that can only take the value 0. This is mainly useful for the 'reduce mode' of transformMultiArray() and combineTwoMultiArrays(), because these functions require the source and destination arrays to have the same number of dimensions.

The range of i must be 0 <= i <= N. The new dimension will become the i'th index, and the old indices from i upwards will shift one place to the right.

Usage:

Suppose we want have a 2D array and want to create a 1D array that contains the row average of the first array.

            typedef MultiArrayShape<2>::type Shape2;
            MultiArray<2, double> original(Shape2(40, 30));

            typedef MultiArrayShape<1>::type Shape1;
            MultiArray<1, double> rowAverages(Shape1(30));

            // temporarily add a singleton dimension to the destination array
            transformMultiArray(srcMultiArrayRange(original),
                                destMultiArrayRange(rowAverages.insertSingletonDimension(0)),
                                FindAverage<double>());
MultiArrayView subarray ( const difference_type p,
const difference_type q 
) const

create a rectangular subarray that spans between the points p and q, where p is in the subarray, q not.

Usage:

            // create a 3D array of size 40x30x20
            typedef MultiArray<3, double>::difference_type Shape;
            MultiArray<3, double> array3(Shape(40, 30, 20));

            // get a subarray set is smaller by one element at all sides
            MultiArrayView <3, double> subarray = array3.subarray(Shape(1,1,1), Shape(39, 29, 19));
MultiArrayView<N, T, StridedArrayTag> stridearray ( const difference_type s) const

apply an additional striding to the image, thereby reducing the shape of the array. for example, multiplying the stride of dimension one by three turns an appropriately layed out (interleaved) rgb image into a single band image.

MultiArrayView<N, T, StridedArrayTag> transpose ( ) const

Transpose an array. If N==2, this implements the usual matrix transposition. For N > 2, it reverses the order of the indices.

Usage:

            typedef MultiArray<2, double>::difference_type Shape;
            MultiArray<2, double> array(10, 20);

            MultiArray<2, double, StridedArrayTag> transposed = array.transpose();

            for(int i=0; i<array.shape(0), ++i)
                for(int j=0; j<array.shape(1); ++j)
                    assert(array(i, j) == transposed(j, i));

Reimplemented in Matrix< T, ALLOC >, and Matrix< T >.

MultiArrayView< N, T, StridedArrayTag > permuteDimensions ( const difference_type s) const

permute the dimensions of the array. The function exchanges the meaning of the dimensions without copying the data. In case of a 2-dimensional array, this is simply array transposition. In higher dimensions, there are more possibilities.

Usage:

            typedef MultiArray<2, double>::difference_type Shape;
            MultiArray<2, double> array(10, 20);

            MultiArray<2, double, StridedArrayTag> transposed = array.permuteDimensions(Shape(1,0));

            for(int i=0; i<array.shape(0), ++i)
                for(int j=0; j<array.shape(1); ++j)
                    assert(array(i, j) == transposed(j, i));
MultiArrayView< N, T, StridedArrayTag > permuteStridesAscending ( ) const

Permute the dimensions of the array so that the strides are in ascending order. Determines the appropriate permutation and then calls permuteDimensions().

MultiArrayView< N, T, StridedArrayTag > permuteStridesDescending ( ) const

Permute the dimensions of the array so that the strides are in descending order. Determines the appropriate permutation and then calls permuteDimensions().

difference_type strideOrdering ( ) const

Compute the ordering of the strides in this array. The result is describes the current permutation of the axes relative to the standard ascending stride order.

MultiArrayView< N, T, C >::difference_type strideOrdering ( difference_type  strides) [static]

Compute the ordering of the given strides. The result is describes the current permutation of the axes relative to the standard ascending stride order.

difference_type_1 elementCount ( ) const

number of the elements in the array.

Reimplemented in Matrix< T, ALLOC >, and Matrix< T >.

difference_type_1 size ( ) const

number of the elements in the array. Same as elementCount(). Mostly useful to support the std::vector interface.

const difference_type& shape ( ) const

return the array's shape.

return the array's size at a certain dimension.

return the array's shape at a certain dimension (same as size(n)).

const difference_type& stride ( ) const

return the array's stride for every dimension.

difference_type_1 stride ( int  n) const

return the array's stride at a certain dimension.

bool operator== ( MultiArrayView< N, U, C1 > const &  rhs) const

check whether two arrays are elementwise equal.

bool operator!= ( MultiArrayView< N, U, C1 > const &  rhs) const

check whether two arrays are not elementwise equal. Also true when the two arrays have different shapes.

bool isInside ( difference_type const &  p) const

check whether the given point is in the array range.

NormTraits<MultiArrayView>::SquaredNormType squaredNorm ( ) const

Compute the squared Euclidean norm of the array (sum of squares of the array elements).

Reimplemented in Matrix< T, ALLOC >, and Matrix< T >.

NormTraits< MultiArrayView< N, T, C > >::NormType norm ( int  type = 2,
bool  useSquaredNorm = true 
) const

Compute various norms of the array. The norm is determined by parameter type:

  • type == 0: maximum norm (L-infinity): maximum of absolute values of the array elements
  • type == 1: Manhattan norm (L1): sum of absolute values of the array elements
  • type == 2: Euclidean norm (L2): square root of squaredNorm() when useSquaredNorm is true,
    or direct algorithm that avoids underflow/overflow otherwise.

Parameter useSquaredNorm has no effect when type != 2. Defaults: compute L2 norm as square root of squaredNorm().

pointer data ( ) const

return the pointer to the image data

bool hasData ( ) const

returns true iff this view refers to valid data, i.e. data() is not a NULL pointer. (this is false after default construction.)

traverser traverser_begin ( )

returns the N-dimensional MultiIterator pointing to the first element in every dimension.

const_traverser traverser_begin ( ) const

returns the N-dimensional MultiIterator pointing to the const first element in every dimension.

traverser traverser_end ( )

returns the N-dimensional MultiIterator pointing beyond the last element in dimension N, and to the first element in every other dimension.

const_traverser traverser_end ( ) const

returns the N-dimensional const MultiIterator pointing beyond the last element in dimension N, and to the first element in every other dimension.


Member Data Documentation

difference_type m_shape [protected]

the shape of the image pointed to is stored here.

the strides (offset of a sample to the next) for every dimension are stored here.

pointer m_ptr [protected]

pointer to the image.


The documentation for this class was generated from the following file:

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de)
Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany

html generated using doxygen and Python
vigra 1.7.0 (Thu Aug 25 2011)