Reference documentation for deal.II version Git 282b7d48aa 20200330 20:24:33 +0200

Public Member Functions  
Reference (const Accessor *accessor, const bool dummy)  
operator number () const  
const Reference &  operator= (const number n) const 
const Reference &  operator+= (const number n) const 
const Reference &  operator= (const number n) const 
const Reference &  operator*= (const number n) const 
const Reference &  operator/= (const number n) const 
Private Attributes  
const Accessor *  accessor 
Reference class. This is what the accessor class returns when you call the value() function. The reference acts just as if it were a reference to the actual value of a matrix entry, i.e. you can read and write it, you can add and multiply to it, etc, but since the matrix does not give away the address of this matrix entry, we have to go through functions to do all this.
The constructor takes a pointer to an accessor object that describes which element of the matrix it points to. This creates an ambiguity when one writes code like iterator>value()=0 (instead of iterator>value()=0.0), since the right hand side is an integer that can both be converted to a number
(i.e., most commonly a double) or to another object of type Reference
. The compiler then complains about not knowing which conversion to take.
For some reason, adding another overload operator=(int) doesn't seem to cure the problem. We avoid it, however, by adding a second, dummy argument to the Reference constructor, that is unused, but makes sure there is no second matching conversion sequence using a oneargument right hand side.
The testcase oliver_01 checks that this actually works as intended.
Definition at line 219 of file sparse_matrix.h.
SparseMatrixIterators::Accessor< number, false >::Reference::Reference  (  const Accessor< number, false > *  accessor, 
const bool  dummy  
) 
Constructor. For the second argument, see the general class documentation.
SparseMatrixIterators::Accessor< number, false >::Reference::operator number  (  )  const 
Conversion operator to the data type of the matrix.
const Reference& SparseMatrixIterators::Accessor< number, false >::Reference::operator=  (  const number  n  )  const 
Set the element of the matrix we presently point to to n
.
const Reference& SparseMatrixIterators::Accessor< number, false >::Reference::operator+=  (  const number  n  )  const 
Add n
to the element of the matrix we presently point to.
const Reference& SparseMatrixIterators::Accessor< number, false >::Reference::operator=  (  const number  n  )  const 
Subtract n
from the element of the matrix we presently point to.
const Reference& SparseMatrixIterators::Accessor< number, false >::Reference::operator*=  (  const number  n  )  const 
Multiply the element of the matrix we presently point to by n
.
const Reference& SparseMatrixIterators::Accessor< number, false >::Reference::operator/=  (  const number  n  )  const 
Divide the element of the matrix we presently point to by n
.

private 
Pointer to the accessor that denotes which element we presently point to.
Definition at line 268 of file sparse_matrix.h.