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# Documentation

### Contents

Add lifting steps to lifting scheme

## Description

LSN = addlift(LS,ELS) returns the new lifting scheme LSN obtained by appending the elementary lifting step ELS to the lifting scheme LS.

LSN = addlift(LS,ELS,'begin') prepends the specified elementary lifting step.

ELS is either a cell array (see lsinfo)

```{TYPEVAL, COEFS, MAX_DEG}
```

or a structure (see liftfilt)

```struct('type',TYPEVAL,'value',LPVAL)
```

with

```LPVAL = laurpoly(COEFS, MAX_DEG)
```

If ELS is a sequence of elementary lifting steps, stored in a cell array or an array of structures, then each of the elementary lifting steps is added to LS.

This example shows how to start with the Haar lifting scheme and add a primal lifting step.

```LSbegin = liftwave('haar');
```

Display the lifting scheme.

```displs(LSbegin);
```
```LSbegin = {...
'd'             [ -1.00000000]  [0]
'p'             [  0.50000000]  [0]
[  1.41421356]  [  0.70710678]  []
};
```

Create a primal lifting step.

```pstep = { 'p', [-1 2 -1]/4 , 1 };
```

```LSend = addlift(LSbegin,pstep);
```

Display the final lifting scheme.

```displs(LSend);
```
```LSend = {...
'd'             [ -1.00000000]                          [0]
'p'             [  0.50000000]                          [0]
'p'             [ -0.25000000  0.50000000 -0.25000000]  [1]
[  1.41421356]  [  0.70710678]                          []
};
```