Visualizer for Loss Functions

Visualize one or multiple loss functions.

Super class

vistool::Visualizer -> VisualizerLossFuns

Public fields

losses

(`list`)
List of LossFunction objects.

task_type

(`character(1)`)
Task type (regr or classif).

y_pred

(`numeric()`)
Predicted values.

y_true

(`numeric()`)
True values.

input_type

(`character(1)`)
Input scale for classification tasks: `"score"` (margin‑based, default) or `"probability"`.

Methods

Public methods

• VisualizerLossFuns$new()

• VisualizerLossFuns$plot()

• VisualizerLossFuns$add_points()

• VisualizerLossFuns$clone()

Inherited methods

• vistool::Visualizer$resolve_layer_colors()
• vistool::Visualizer$save()
• vistool::Visualizer$set_theme()
• vistool::Visualizer$theme()

---

Method new()

Creates a new instance of this [R6][R6::R6Class] class.

Usage

VisualizerLossFuns$new(
  losses,
  y_pred = NULL,
  y_true = NULL,
  input_type = "auto",
  ...
)

Arguments

losses

(`list`)
List of LossFunction objects.

y_pred

(`numeric()`)
Predicted values. Optional.

y_true

(`numeric()`)
True values. Optional.

input_type

(`character(1)`)
Desired input scale. One of `"auto"`, `"score"`, `"probability"`. `"auto"` (default) chooses the common `input_default` of the supplied losses.

...

Additional arguments (currently unused).

---

Method plot()

Create and return the ggplot2 plot with model-specific layers.

Usage

VisualizerLossFuns$plot(
  n_points = 1000L,
  y_curves = "both",
  line_width = NULL,
  line_col = NULL,
  line_type = NULL,
  ...
)

Arguments

n_points

(`integer(1)`)
Number of points to use for plotting the loss functions. Default is 1000.

y_curves

(`character(1)`)
When `input_type = "probability"`, choose which curves to display: `"both"`, `"y1"`, or `"y0"`. Default is "both".

line_width

(`numeric()`)
Line widths for different loss functions. If NULL, uses default width of 1.2 for all lines.

line_col

(`character()`)
Line colors for different loss functions. If NULL, uses automatic color assignment.

line_type

(`character()`)
Line types for different loss functions. If NULL, uses "solid" for all lines.

...

Additional arguments passed to the parent plot method.

Returns

A ggplot2 object.

---

Method add_points()

Add points to the loss function visualization with optional vertical lines. Points are automatically positioned on the loss curve by evaluating the selected loss function at the given x-coordinates.

Usage

VisualizerLossFuns$add_points(
  x,
  loss_id = NULL,
  show_line = TRUE,
  color = "auto",
  size = NULL,
  alpha = NULL,
  line_color = NULL,
  line_alpha = NULL
)

Arguments

x

(`numeric()`)
x-coordinates where to place points on the loss curves. These represent the residual values (y-f for regression, y*f for classification scores, or probabilities for classification probability mode).

loss_id

(`character(1)`)
ID of the loss function to use for y-value calculation. If NULL (default), uses the first loss function.

show_line

(`logical(1)`)
If TRUE (default), draws vertical lines from points to x-axis.

color

(`character(1)`)
Color of the points and lines. Use "auto" for automatic color assignment. Default is "auto".

size

(`numeric(1)`)
Size of the points. If NULL, uses theme$point_size. Default is NULL.

alpha

(`numeric(1)`)
Alpha transparency of points and lines. If NULL, uses theme$alpha. Default is NULL.

line_color

(`character(1)`)
Color of vertical lines. If NULL, uses the same color as points.

line_alpha

(`numeric(1)`)
Alpha transparency of vertical lines. If NULL, uses alpha * 0.7.

---

Method clone()

The objects of this class are cloneable with this method.

Usage

VisualizerLossFuns$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.