The module "mat2layers" of the Mastrave modelling library

Copyright and license notice of the function mat2layers

Copyright © 2006,2009,2011,2012 Daniele de Rigo

The file mat2layers.m is part of Mastrave.

Mastrave is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Mastrave is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with Mastrave. If not, see http://www.gnu.org/licenses/.

Function declaration

layer_array = mat2layers( matrix                     , 
                          valuemap = @sortable2index )

Description

Module for transforming a matrix matrix into a three-dimensional array of boolean layers. The matrix values are mapped into corresponding indices by means of the optional input argument valuemap . If valuemap is not passed, the function @sortable2index is used instead. Each layer has the same size of the original matrix . The elements of the i-th layer are true where the corresponding elements of matrix are mapped into the index i.

Input arguments

 matrix            ::matrix,!sparse::
                   Numeric, charachter or cell-array matrix (whose number
                   of dimensions cannot exceed 2).

 valuemap          ::function_handle::
                   Handle to a custom function for mapping the elements
                   of  matrix  into corresponding indices. The function
                   is expected to accept as input argument a 
                   ::matrix,!sparse:: and to return a matrix of positive
                   integer indices.
                   If omitted, the default value is @sortable2index.

Example of usage

   % Basic usage:
   M1  = [1 3 2;2 1 1]
   M2  = m1*10 -15
   LM1 = mat2layers( M1 )
   LM2 = mat2layers( M2 )
   assert( isequal( LM1, LM2 ) )
   rev = @(L)sum( 1-cumsum( L, 3 ), 3)+1
   assert( isequal( M1, rev( LM1 )       ) )
   assert( isequal( M2, rev( LM1 )*10-15 ) )

   % Passing as input a cell-array of strings
   C1  = {'foo' 'bar' '' 'foo' 'foo' 'bar'}
   C2  = {'foo' 'bar' '';'foo' 'foo' 'bar'}
   LC1 = mat2layers( C1 )
   LC2 = mat2layers( C2 )

   % Passing a custom valuemap function
   LM3 = mat2layers( M1, @(x)(x>=2)+1   )
   LM4 = mat2layers( M1, @(x)mod(x,2)+1 )

See also:
   mat2multi, multi2mat, mdeal



Keywords:
   multidimensional-array, data-transformation, matrix, boolean



Version: 0.8.1

Support

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