The module "mat2groups" of the Mastrave modelling library
Copyright © 2005,2006,2007,2008,2009,2010,2011 Daniele de Rigo
The file mat2groups.m is part of Mastrave.
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groups = mat2groups( matrix , groups_length , mode = '--none' )
Returns a sparse matrix groups whose nonzeros elements are the elements of the input argument matrix . groups has an amount of columns equal to the number of elements of the vector of non-negative integers groups_length . Each column of groups has an amount of rows equal to the corresponding element of groups_length . Depending on the value of mode , the elements of each groups column may be in the same order of the corresponding elements of matrix (default behaviour), or may be ordered in ascending or descending order.
matrix ::numeric:: Matrix of numbers. groups_length ::natural:: Vector containing the desired length of each group in which matrix has to be splitted. mode ::string:: Direction in which each column of the cell-array groups will be sorted. Valid modes are: mode │ meaning ──────────────┼─────────────────────────────────────── 'none' │ Leave the elements of groups in '--none' │ the same order of those of matrix : (default) │ nonzeros( groups ) == matrix (:) . ──────────────┼─────────────────────────────────────── 'ascend' │ Sort in ascending order. '--ascend' │ ──────────────┼─────────────────────────────────────── 'descend' │ Sort in descending order. '--descend' │
% Basic conversion n_elems = [2 0 3 4 0 0 5 3 ] data = randn( 1, sum(n_elems) ) sp_data = mat2groups( data, n_elems ); full( sp_data ) all( nonzeros(sp_data) == data(:) ) % Adding sort for no-empty elements sp_data = mat2groups( data, n_elems, '--descend' ); full( sp_data ) sp_data = mat2groups( data, n_elems, '--ascend' ); full( sp_data ) % Difference between mat2groups and score [rev_id, sorted_data, sort_id] = score( sp_data , '--ascend' ); full( sorted_data )
See also: mat2multi, multi2mat Keywords: matrices, sparse matrices Version: 0.5.1
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