Description of dense

dense<int MemLoc=internal>		Programmers Guide
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Category:containers,selectors

Component type:type

Description

TwoD Storage Type Selectors

This is the most common way of storing matrices, and consists of one contiguous piece of memory that is divided up into rows or columns of equal length. The following example shows how a matrix can be mapped to linear memory in either a row-major or column-major fashion.

 [ 1 2 3 ]
 [ 4 5 6 ]
 [ 7 8 9 ]
  
 row major:
 [ 1 2 3 4 5 6 7 8 9 ]
  
 column major:
 [ 1 4 7 2 5 8 3 6 9 ]

OneD Storage Type Selectors

This specifies a normal dense vector to be used as the OneD part of matrix with array storage.

Example

In swap_rows.cc:

  typedef matrix< double,
                  rectangle<>, 
                  dense<external>,
                  column_major>::type Matrix; 
  const Matrix::size_type N = 3;
  Matrix::size_type large;
  double dA[] = { 1, 3, 2, 1.5, 2.5, 3.5, 4.5, 9.5, 5.5 };
  Matrix A(dA, N, N);
  //  Find the largest element in column 1.
  large = max_index(A[0]);
  // Swap the first row with the row containing the largest
  // element in column 1.
  swap( rows(A)[0] , rows(A)[large]);

More examples can be found in general_matvec_mult.cc

Definition

matrix.h

Template Parameters

Parameter	Description	Default
`MemLoc`	Specify whether the memory used is "owned" by the matrix or if it was provided to the matrix from some external source (with a pointer to some data)	`internal`

Model of

Members

Member	Where defined	Description
`size_type`
`enum { id = DENSE, oned_id, ext=MemLoc, issparse=0, index }`

New members

Notes

See also