 Usage:  {ur, h} = chbase (u, oldh)  
 
 Input:

  u                      vector commands 
                         
  oldh                   n x 1 array old coefficients 
                         
 Output:

  ur                     vector commands 
                         
  h                      m x p array new coefficients 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
