function a = indicator ( m, n ) %*****************************************************************************80 % %% INDICATOR sets the indicator matrix. % % Discussion: % % The indicator matrix has entries which reveal their row and column. % % That makes it useful for testing printing algorithms, or schemes % which select a submatrix, or extract a particular value from a % matrix, or in general, any situation in which it would be useful % to know the origin of a value that was extracted from a matrix. % % Example: % % M = 3, N = 4 % % A = % % 11 12 13 14 % 21 22 23 24 % 31 32 33 34 % % Properties: % % For a particular A, no two entries are equal. % % A is generally not symmetric: A' /= A. % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 26 October 2007 % % Author: % % John Burkardt % % Parameters: % % Input, integer M, N, the number of rows and columns % of the matrix A. % % Output, real A(M,N), the matrix. % a = zeros ( m, n ); k = 10^( i4_log_10 ( n ) + 1 ); for i = 1 : m for j = 1 : n a(i,j) = i * k + j; end end return end