linalg::slice Class Reference

Vector slices corresponding to GNU Octave ranges. More...

#include <linalg.hpp>

List of all members.

Public Member Functions
	slice (size_t a, size_t b, size_t k=1)
	Create a vector slice.
slice	operator() (size_t a, size_t b, size_t k=1)
slice	set (size_t a, size_t b, size_t k=1)
size_t	begin () const
size_t	end () const
size_t	stride () const
Private Member Functions
	slice ()
	Empty and private default constructor.
Private Attributes
size_t	beg
size_t	fin
size_t	str

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Detailed Description

Vector slices corresponding to GNU Octave ranges.

Vector slices are useful for certain vectorisation routines and for referring to rows, columns, or equally spaced chunks of a vector or a matrix. Set a begininning and an end for the stride, and a step size, and this will be the elements that can be indexed by this slice in a vector or matrix. E.g. if the beginning is 2, the end 8, and the stride is 2, then this refers to the slice [2, 4, 6, 8]. The default stride is 1.

Unlike GNU Octave slices, there is no shorthand for referring to the entirety of a column or row of a matrix. Must instead create a slice for that purpose as s(1,n) where n is the number of rows or columns respectively.

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Constructor & Destructor Documentation

linalg::slice::slice	(	size_t	a,
		size_t	b,
		size_t	k = 1
	)

Create a vector slice.

Parameters:

	a	- Beginning of the slice.
	b	- End of the slice.
	k	- Stride (default is 1).

                                           {
    set(a,b,k);
  } 

linalg::slice::slice

(

)

[inline, private]

Empty and private default constructor.

{};

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Member Function Documentation

slice linalg::slice::operator()	(	size_t	a,
		size_t	b,
		size_t	k = 1
	)

For setting the slice parameters anew.

Indices start from 1.

Parameters:

	a	- Beginning of the slice.
	b	- End of the slice.
	k	- Stride (default is 1).

                                                      {
    return set(a,b,k);
  }

slice linalg::slice::set	(	size_t	a,
		size_t	b,
		size_t	k = 1
	)

                                               {
    if(b < a){
      badArgument exc;
      exc.reason = 
        "Invalid arguments to slice::set. "
        "Right endpoint must be greater than left endpoint.";
      exc.line = __LINE__; exc.file = __FILE__;
      throw exc;
    }
    else if(k==0){
      badArgument exc;
      exc.reason = 
        "Invalid arguments to slice::set. "
        "Cannot take zero stride.";
      exc.line = __LINE__; exc.file = __FILE__;
      throw exc;
    }
    else if( k > b-a){
      badArgument exc;
      exc.reason = "Invalid arguments to slice::set. " 
        "Step size cannot be greater than range.";
      exc.line = __LINE__; exc.file = __FILE__;
      throw exc;
    }
    beg = a-1;
    fin = b-1;
    str = k;
    return *this;
  }

size_t linalg::slice::begin

(

)

const [inline]

{return beg;};

size_t linalg::slice::end

(

)

const [inline]

{return fin;};

size_t linalg::slice::stride

(

)

const [inline]

{return str;};

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Member Data Documentation

size_t linalg::slice::beg [private]

size_t linalg::slice::fin [private]

size_t linalg::slice::str [private]

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

• include/linalg.hpp
• linalg.cpp