R: Lower-triangular matrix

lower {ecodist} | R Documentation

## Lower-triangular matrix

### Description

Convert a symmetric distance matrix to a column order lower triangular matrix.

### Usage

      lower(m)

### Arguments

`m` | a symmetric distance matrix.

### Details

Converts a symmetric matrix, for example a dissimilarity matrix, into a column order lower-triangular matrix. This may be useful to format the input for certain clustering and ordination functions. Note that `lower()` used on a 1x1 matrix will return the single element, which may not be the correct behavior in all cases, while `full()` used on a single element will return a 2x2 matrix.

### Value

column order lower triangular matrix.

### Author(s)

Sarah Goslee

### See Also

`full`, `fixdmat`

### Examples

    x.vec <- seq_len(6)
    x.vec

    # Make an R-style column order symmetric matrix
    full(x.vec)

    # Extract the lower triangle from a symmetric matrix
    # in column order
    lower(full(x.vec))

    # Convert to or from a row order symmetric matrix
    fixdmat(x.vec)
    lower(fixdmat(x.vec))

    fixdmat(c(1, 2, 4, 3, 5, 6))

[Package ecodist version 2.0.7 Index]