# Documentation

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# wrcoef

Reconstruct single branch from 1-D wavelet coefficients

## Syntax

```X = wrcoef('type',C,L,'wname',N) X = wrcoef('type',C,L,Lo_R,Hi_R,N) X = wrcoef('type',C,L,'wname') X = wrcoef('type',C,L,Lo_R,Hi_R) ```

## Description

`wrcoef` reconstructs the coefficients of a one-dimensional signal, given a wavelet decomposition structure (`C` and `L`) and either a specified wavelet (`'wname'`, see `wfilters` for more information) or specified reconstruction filters (`Lo_R` and `Hi_R`).

`X = wrcoef('type',C,L,'wname',N)` computes the vector of reconstructed coefficients, based on the wavelet decomposition structure `[C,L]` (see `wavedec` for more information), at level `N`. `'wname'` is a character vector containing the wavelet name.

Argument `'type'` determines whether approximation (`'type'` `= 'a'`) or detail (`'type'` `= 'd'`) coefficients are reconstructed. When `'type'` ```= 'a'```, `N` is allowed to be 0; otherwise, a strictly positive number `N` is required. Level `N` must be an integer such that `N``length(L)-2`.

`X = wrcoef('type',C,L,Lo_R,Hi_R,N)` computes coefficients as above, given the reconstruction filters you specify.

`X = wrcoef('type',C,L,'wname')` and ```X = wrcoef('type',C,L,Lo_R,Hi_R)``` reconstruct coefficients of maximum level `N = length(L)-2`.

## Examples

```% The current extension mode is zero-padding (see `dwtmode`). % Load a one-dimensional signal. load sumsin; s = sumsin; % Perform decomposition at level 5 of s using sym4. [c,l] = wavedec(s,5,'sym4'); % Reconstruct approximation at level 5, % from the wavelet decomposition structure [c,l]. a5 = wrcoef('a',c,l,'sym4',5); % Using some plotting commands, % the following figure is generated. ```