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read

Read values of WPTREE

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    Syntax

    value = read(T,propname,propparam)

    Description

    value = read(T,propname,propparam) returns the value of the wavelet packet tree T property specified by propname. propparam is an optional parameter depending on the value of propname.

    You can specify one or more properties in any order. propname-propparam arguments must appear after other arguments. For example, [value1,value2,value3,value4] = read(T,propname1,propname2,propname3,propparam3,propname4,propparam4).

    example

    Examples

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    Open Live Script

    Create a wavelet packet tree.

    x = rand(1,512);
t = wpdec(x,3,"db3");
t = wpjoin(t,[4;5]);

    Display the tree.

    plot(t)

    Figure contains 2 axes objects and other objects of type uimenu. Axes object 1 with title Tree Decomposition contains 21 objects of type line, text. Axes object 2 with title data for node: 0 or (0,0). contains an object of type line.

    Obtain the size of the data at every node in ascending node index order.

    sAll = read(t,"sizes")
    sAll = 11×2

     1   512
     1   258
     1   258
     1   131
     1   131
     1   131
     1   131
     1    68
     1    68
     1    68
      ⋮

    Obtain the size of the data at nodes of indices 0, 4 and 5.

    sNod = read(t,"sizes",[0,4,5])
    sNod = 3×2

     1   512
     1   131
     1   131

    Obtain the entropy of all the nodes.

    eAll = read(t,"ent")
    eAll = 11×1

  116.3597
   45.9147
   39.1646
  -30.2074
   17.6607
   20.8560
   18.8364
 -114.8913
   11.4664
    9.2578
      ⋮

    Obtain the entropy at nodes of indices 0, 4 and 5.

    eNod = read(t,"ent",[0,4,5])
    eNod = 3×1

  116.3597
   17.6607
   20.8560

    Obtain the wavelet filters and wavelet coefficients.

    [loD,hiD,loR,hiR] = read(t,"wfilters");
[loD1,loR1,hiD1,hiR1] = read(t,"wfilters","l","wfilters","h");
[max(abs(loD-loD1)) max(abs(hiD-hiD1)) ...
    max(abs(loR-loR1)) max(abs(hiR-hiR1))]
    ans = 1×4

     0     0     0     0

    Obtain the wavelet coefficients at all nodes.

    dAll = read(t,"data");

    Obtain the wavelet coefficients at nodes of indices 4 and 5.

    dNod = read(t,"data",[4;5]);
[ent,cfs4,cfs5]  = read(t,"ent","cfs",4,"cfs",5);
[max(abs(dNod{1}-cfs4)) max(abs(dNod{2}-cfs5))]
    ans = 1×2

     0     0

    Plot the coefficients at node index 4.

    plot(cfs4)
title("Node 4 Wavelet Coefficients")

    Figure contains an axes object. The axes object with title Node 4 Wavelet Coefficients contains an object of type line.

    Input Arguments

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    Wavelet packet tree, specified as a WPTREE object.

    Wavelet packet tree property name, specified as one of the following:

    Property Name (propname)

    Property Parameter (propparam)

    "ent", "ento" or "sizes" (see wptree)

    Without propparam or with propparam = Vector of node indices, value contains the entropy (or optimal entropy, or size) of the tree nodes in ascending node index order.

    "cfs"

    With propparam = One terminal node index. value = read(T,"cfs",NODE) is equivalent to value = read(T,"data",NODE) and returns the coefficients of the terminal node NODE.

    "entName", "entPar", "wavName" (see wptree) or "allcfs"

    Without propparam. value = read(T,"allcfs") is equivalent to value = read(T,"data"). value contains the desired information in ascending node index order of the tree nodes.

    "wfilters" (see wfilters)

    Without propparam or with propparam = "d","r","l","h".

    "data"

    Without propparam or with propparam = One terminal node index or propparam = Column vector of terminal node indices. In this last case, value is a cell array. Without propparam, value contains the coefficients of the tree nodes in ascending node index order.

    Example: [value1,value2,value3,value4] = read(T,"wavName","allcfs","cfs",4,"wfilters","h")

    Parameter associated with the property propname, specified as an integer or vector of integers.

    Version History

    Introduced before R2006a

    See Also

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