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umap

Short Description

sm.tl.umap: The function allows users to perform dimensionality reduction using UMAP

Function

umap(adata, use_layer=None, use_raw=False, log=False, n_neighbors=15, n_components=2, metric='euclidean', min_dist=0.1, random_state=0, label='umap', **kwargs)

Parameters:

Name Type Description Default
adata

AnnData Object

required
use_layer

string, optional
Pass name of any Layer in AnnData. The default is None and adata.X is used.

 None
use_raw

bool, optional
If set to True, values in adata.raw.X will be used. The default is False.

 False
log

bool, optional
If set to True, the data will natural log transformed using np.log1p(). The default is False.

 False
n_neighbors

int, optional
The size of local neighborhood (in terms of number of neighboring sample points) used for manifold approximation. Larger values result in more global views of the manifold, while smaller values result in more local data being preserved. In general values should be in the range 2 to 100. The default is 15.

 15
n_components

int, optional
The dimension of the space to embed into. This defaults to 2 to provide easy visualization, but can reasonably be set to any integer value in the range 2 to 100. The default is 2.

 2
metric

TYPE, optional
The metric to use to compute distances in high dimensional space. Check https://umap-learn.readthedocs.io/en/latest/api.html for all available options. The default is 'euclidean'.

 'euclidean'
min_dist

float, optional
The effective minimum distance between embedded points. Smaller values will result in a more clustered/clumped embedding where nearby points on the manifold are drawn closer together, while larger values will result on a more even dispersal of points. The value should be set relative to the spread value, which determines the scale at which embedded points will be spread out. The default is 0.1.

 0.1
random_state

int, optional
If int, random_state is the seed used by the random number generator; If RandomState instance, random_state is the random number generator; If None, the random number generator is the RandomState instance used by np.random. The default is 0.

 0
label

string, optional
Key used to save the embeddings. Check adata.obsm[label] for results. The default is 'umap'.

 'umap'
**kwargs

Other umap parameters. Check https://umap-learn.readthedocs.io/en/latest/api.html

{}

Returns:

Name Type Description
adata

Modified AnnData object Embedding stored in adata.obsm[label].

 
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# Run UMAP
adata = sm.tl.umap(adata)

# plot results
sm.pl.umap(adata)
Source code in scimap/tools/_umap.py 
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def umap (adata, use_layer=None, use_raw=False, log=False,
          n_neighbors=15, n_components=2, metric='euclidean',min_dist=0.1, random_state=0, 
          label='umap', **kwargs):
    """
Parameters:

    adata : AnnData Object  

    use_layer : string, optional  
        Pass name of any `Layer` in AnnData. The default is `None` and `adata.X` is used.

    use_raw : bool, optional  
        If set to `True`, values in `adata.raw.X` will be used. The default is False.

    log : bool, optional  
        If set to `True`, the data will natural log transformed using `np.log1p()`. The default is False.

    n_neighbors : int, optional  
        The size of local neighborhood (in terms of number of neighboring sample points) 
        used for manifold approximation. Larger values result in more global views of the manifold, 
        while smaller values result in more local data being preserved. In general 
        values should be in the range 2 to 100. The default is 15.

    n_components : int, optional  
        The dimension of the space to embed into. This defaults to 2 to provide easy visualization, 
        but can reasonably be set to any integer value in the range 2 to 100. The default is 2.

    metric : TYPE, optional  
        The metric to use to compute distances in high dimensional space. 
        Check `https://umap-learn.readthedocs.io/en/latest/api.html` for all available 
        options. The default is 'euclidean'.

    min_dist : float, optional  
        The effective minimum distance between embedded points. Smaller values will 
        result in a more clustered/clumped embedding where nearby points on the manifold 
        are drawn closer together, while larger values will result on a more even 
        dispersal of points. The value should be set relative to the spread value, 
        which determines the scale at which embedded points will be spread out. The default is 0.1.

    random_state : int, optional  
        If int, random_state is the seed used by the random number generator; 
        If RandomState instance, random_state is the random number generator; 
        If None, the random number generator is the RandomState instance used by np.random. The default is 0.

    label : string, optional  
        Key used to save the embeddings. 
        Check `adata.obsm[label]` for results. The default is 'umap'.

    **kwargs : Other `umap` parameters. Check `https://umap-learn.readthedocs.io/en/latest/api.html`  

Returns:

    adata : Modified AnnData object
        Embedding stored in `adata.obsm[label]`.

Example:
```python
# Run UMAP
adata = sm.tl.umap(adata)

# plot results
sm.pl.umap(adata)
```

    """

    # adata_layer=None;use_raw=False;log=False;n_neighbors=15;n_components=2;metric='euclidean';min_dist=0.1;
    # random_state=0;
    # load data
    if use_layer is not None:
        data = adata.layers[use_layer]
    elif use_raw is True:
        data = adata.raw.X
    else:
        data = adata.X

    # log the data if user requests
    if log is True:
        data = np.log1p(data)


    # embedding
    embedding = um.UMAP(n_neighbors=n_neighbors,
                          n_components=n_components,
                          metric=metric,
                          min_dist=min_dist,
                          random_state=random_state).fit_transform(data)

    # plot
    #plt.scatter(embedding[:, 0], embedding[:, 1], s=5)

    # return data
    adata.obsm[label] = embedding
    return adata