It is a function that returns a matrix X with elements smaller than U.
  For this purpose all elements superior to U are truncated to U.

  After starting the main routine just type the following command at the
  prompt:
  X1=threshold2d(X,U);
  [X1 X2]=threshold2d(X,U);

  Input:
  X   is a 2D matrix that needs be truncated.
  U   is the threshold of matrix X. He makes all values higher than U are set to U.
      U can be the matrix X or a scalar value.

  Output:
  X1  is the truncated matrix to threshold U.
  X2  [Optional] is the complement of the truncated matrix to threshold U. 
      X2 + X1 = X


  For help, bug reports and feature suggestions, please visit:
  http://nongnu.org/bsltl/

Package: bsltl