g_covariance: Visualization of Covariance Matrix

In tern.mmrm: Tables and Graphs for Mixed Models for Repeated Measures (MMRM)

Visualization of Covariance Matrix

Description

Plot of covariance (or correlation) matrix as a function of lag or time. The covariance structure is vectorized internally and lag or time distances are computed and can be used for visualization.

Usage

g_covariance(
  vcov_matrix,
  time_prefix = NULL,
  x_var = c("lag", "time_diff"),
  xlab = NULL,
  ylab = ""
)

Arguments

vcov_matrix	(matrix) symmetric covariance matrix with identical row and column names.
time_prefix	(string) string in the names of vcov_matrix that precedes the time point value.
x_var	(string) can be lag or time_diff for lag or time difference, respectively.
xlab	(string or NULL) x-axis label, if NULL then automatically determined from x_var.
ylab	(string) y-axis label.

Details

The default time_prefix value is NULL, which assumes that the names of the input matrix don't have any character string other than time point value. If a time_prefix is specified, this string should appear in front of all the names in vcov_matrix.

Value

The ggplot object.

Examples

vcov_matrix <- matrix(
  c(49, 12, 12, 23),
  nrow = 2, ncol = 2,
  dimnames = list(
    c(1, 2),
    c(1, 2)
  )
)
g_covariance(vcov_matrix, x_var = "time_diff")

tern.mmrm documentation built on Sept. 30, 2024, 9:20 a.m.