cograph (version 1.5.2)

plot_htna: Plot Heterogeneous TNA Network (Multi-Group Layout)

Description

Plots a TNA model with nodes arranged in multiple groups using geometric layouts:

• 2 groups: Bipartite (two vertical columns or horizontal rows)

• 3+ groups: Polygon (nodes along edges of a regular polygon)

Supports triangle (3), rectangle (4), pentagon (5), hexagon (6), and beyond.

Usage

plot_htna(
  x,
  node_list,
  layout = "auto",
  use_list_order = TRUE,
  jitter = TRUE,
  jitter_amount = 0.8,
  jitter_side = "first",
  orientation = "vertical",
  group1_pos = -1.2,
  group2_pos = 1.2,
  curvature = 0.4,
  group1_color = "#ffd89d",
  group2_color = "#a68ba5",
  group1_shape = "circle",
  group2_shape = "square",
  group_colors = NULL,
  group_shapes = NULL,
  angle_spacing = 0.15,
  edge_colors = NULL,
  legend = TRUE,
  legend_position = "topright",
  extend_lines = FALSE,
  scale = 1,
  ...
)

Value

Invisibly returns the result from tplot().

Arguments

x

A tna object or weight matrix.

node_list

List of 2+ character vectors defining node groups.

layout

Layout type: "auto" (default), "bipartite", "polygon", or "circular". When "auto", uses bipartite for 2 groups and polygon for 3+ groups. "circular" places groups along arcs of a circle. Legacy values "triangle" and "rectangle" are supported as aliases for "polygon".

use_list_order

Logical. Use node_list order (TRUE) or weight-based order (FALSE). Only applies to bipartite layout.

jitter

Controls horizontal spread of nodes. Options:

• TRUE (default): Auto-compute jitter based on edge connectivity

• FALSE or 0: No jitter (nodes aligned in columns)

• Numeric (0-1): Amount of jitter (0.3 = spread nodes 30\

• Named list: Manual per-node offsets by label (e.g., list(Wrong = -0.2))

• Numeric vector of length n: Direct x-offsets for each node

Only applies to bipartite layout.

jitter_amount

Base jitter amount when jitter=TRUE. Default 0.5. Higher values spread nodes more toward the center. Only applies to bipartite layout.

jitter_side

Which side(s) to apply jitter: "first", "second", "both", or "none". Default "first" (only first group nodes are jittered toward center). Only applies to bipartite layout.

orientation

Layout orientation for bipartite: "vertical" (two columns, default) or "horizontal" (two rows). Ignored for triangle/rectangle layouts.

group1_pos

Position for first group in bipartite layout. Default -1.2.

group2_pos

Position for second group in bipartite layout. Default 1.2.

curvature

Edge curvature amount. Default 0.4 for visible curves.

group1_color

Color for first group nodes. Default "#ffd89d".

group2_color

Color for second group nodes. Default "#a68ba5".

group1_shape

Shape for first group nodes. Default "circle".

group2_shape

Shape for second group nodes. Default "square".

group_colors

Vector of colors for each group. Overrides group1_color/group2_color. Required for 3+ groups if not using defaults.

group_shapes

Vector of shapes for each group. Overrides group1_shape/group2_shape. Required for 3+ groups if not using defaults.

angle_spacing

Controls empty space at corners (0-1). Default 0.15. Higher values create larger empty angles at vertices. Only applies to triangle/rectangle layouts.

edge_colors

Vector of colors for edges by source group. If NULL (default), uses darker versions of group_colors. Set to FALSE to use default edge color.

legend

Logical. Whether to show a legend. Default TRUE for polygon layouts.

legend_position

Position for legend: "topright", "topleft", "bottomright", "bottomleft", "right", "left", "top", "bottom". Default "topright".

extend_lines

Logical or numeric. Draw extension lines from nodes. Only applies to bipartite layout.

• FALSE (default): No extension lines

• TRUE: Draw lines extending toward the other group (default length 0.1)

• Numeric: Length of extension lines

scale

Scaling factor for high resolution plotting.

...

Additional parameters passed to tplot().

Examples

# --- 2-group bipartite example ---
nodes_2 <- c("Wrong", "Retry", "Right", "Attempt", "Instruction", "Skip",
              "Order", "Correct", "Hint", "Quit", "Clarify", "Question", "Praise")
set.seed(1)
m2 <- matrix(runif(length(nodes_2)^2, 0, 0.3), length(nodes_2), length(nodes_2))
diag(m2) <- 0
dimnames(m2) <- list(nodes_2, nodes_2)

node_types <- list(
  Student = c("Wrong", "Retry", "Right", "Attempt", "Instruction", "Skip"),
  AI = c("Order", "Correct", "Hint", "Quit", "Clarify", "Question", "Praise")
)
plot_htna(m2, node_types)
plot_htna(m2, node_types, jitter_amount = 0.5)

# --- Triangle layout (3 groups) ---
nodes_3 <- c("Explain", "Question", "Feedback",
              "Answer", "Ask", "Attempt",
              "Hint", "Score", "Progress")
m3 <- matrix(runif(81, 0, 0.3), 9, 9)
diag(m3) <- 0
dimnames(m3) <- list(nodes_3, nodes_3)

node_types_3 <- list(
  Teacher = c("Explain", "Question", "Feedback"),
  Student = c("Answer", "Ask", "Attempt"),
  System  = c("Hint", "Score", "Progress")
)
plot_htna(m3, node_types_3)
plot_htna(m3, node_types_3, layout = "triangle")

# --- Rectangle layout (4 groups) ---
nodes_4 <- c("Click", "Type", "Scroll",
              "Validate", "Transform",
              "Display", "Alert",
              "Save", "Load", "Cache")
m4 <- matrix(runif(100, 0, 0.3), 10, 10)
diag(m4) <- 0
dimnames(m4) <- list(nodes_4, nodes_4)

node_types_4 <- list(
  Input   = c("Click", "Type", "Scroll"),
  Process = c("Validate", "Transform"),
  Output  = c("Display", "Alert"),
  Storage = c("Save", "Load", "Cache")
)
plot_htna(m4, node_types_4)