# write

Write values in WPTREE fields

## Syntax

``T = write(T,"cfs",node,coefs)``

## Description

````T = write(T,"cfs",node,coefs)` writes coefficients `coefs` for the terminal node `node`.You can specify one or more pairs of nodes and coefficients in any order. For example, ```T = write(T,"cfs",node1,coefs1,"cfs",node2,coefs2,"cfs",node3,coefs3)```.```

example

## Examples

collapse all

Load a signal. Create a wavelet packet tree.

```load wecg x = wecg; t = wpdec(x,3,"db3"); t = wpjoin(t,[4;5]);```

Plot the tree.

`plot(t)`

The terminal nodes at (2,1), (2,2), and (3,0) have indices 4, 5, and 7, respectively. The terminal node (3,0) corresponds to filtering the signal at the lowest frequency subband. Set the coefficients at the three nodes to 0.

```sNod = read(t,"sizes",[4,5,7]); cfs4 = zeros(sNod(1,:)); cfs5 = zeros(sNod(2,:)); cfs7 = zeros(sNod(3,:)); t = write(t,"cfs",4,cfs4,"cfs",5,cfs5,"cfs",7,cfs7);```

Plot the tree again, and view the data at the root node. The plot shows the reconstruction of the signal after setting the coefficients at the three terminal nodes to 0.

`plot(t)`

## Input Arguments

collapse all

Wavelet packet tree, specified as a `wptree` object.

Terminal node index, specified as an integer.

Coefficients to write for the terminal node, specified as a vector.

The vector must have the correct size for the specified terminal node. You can use `s = read(T,"sizes",node)` to obtain the correct size. To obtain the sizes of multiple terminal nodes, use `s = read(T,"sizes",[node1;node2;…])`, where `node1`, `node2`, …, are the node indices.

## Version History

Introduced before R2006a