Function: largestr
LARGESTR   Keep fixed ratio of largest coefficients
  Usage:  xo=largestr(x,p);
          xo=largestr(x,p,mtype);  
          [xo,N]=largestr(...);

  LARGESTR(x,p) returns an array of the same size as x keeping
  the fraction p of the coefficients. The coefficients with the largest
  magnitude are kept.

  [xo,n]=LARGESTR(xi,p) additionally returns the number of coefficients
  kept.

  *Note:* If the function is used on coefficients coming from a
  redundant transform or from a transform where the input signal was
  padded, the coefficient array will be larger than the original input
  signal. Therefore, the number of coefficients kept might be higher than
  expected.

  LARGESTR takes the following flags at the end of the line of input
  arguments:

    'hard'    Perform hard thresholding. This is the default.

    'wiener'  Perform empirical Wiener shrinkage. This is in between
              soft and hard thresholding.

    'soft'    Perform soft thresholding.  

    'full'    Returns the output as a full matrix. This is the default.

    'sparse'  Returns the output as a sparse matrix.   

  *Note:* If soft- or Wiener thresholding is selected, one less
  coefficient will actually be returned. This is caused by that
  coefficient being set to zero.


  References:
    S. Mallat. A wavelet tour of signal processing. Academic Press, San
    Diego, CA, 1998.
    
    

Url: http://ltfat.github.io/doc/sigproc/largestr.html

See also: largestn.

Package: ltfat