Logarithmic Axes

Mix.install([
  {:plotly_ex, "~> 0.3"},
  {:kino, "~> 0.18"}
])

Section

layout.xaxis.type: "log" switches the x-axis to a base-10 log scale. The data values remain in linear space — Plotly converts them automatically. Set layout.yaxis.type: "log" for the y-axis too.

Note: this duplicates the Fundamentals "Logarithmic Axes" notebook but in the context of Scientific Charts where log plots are typically used (e.g. exponential growth data).

alias Plotly.{Figure, Scatter}

# Exponential growth: y = 2^x
x = Enum.to_list(0..20)
y = Enum.map(x, fn i -> :math.pow(2, i) end)

Figure.new()
|> Figure.add_trace(Scatter.new(x: x, y: y, mode: "lines+markers", name: "y = 2^x"))
|> Figure.update_layout(
  title: "Logarithmic Y-Axis",
  xaxis: %{title: "x"},
  yaxis: %{title: "2^x", type: "log"}
)
|> Plotly.show()

Show both axes log:

# Power law: y = x^2 — straight line on log-log
x2 = [1, 2, 5, 10, 20, 50, 100, 200, 500, 1000]
y2 = Enum.map(x2, fn v -> v * v end)

Figure.new()
|> Figure.add_trace(Scatter.new(x: x2, y: y2, mode: "lines+markers", name: "y = x²"))
|> Figure.update_layout(
  title: "Log-Log Plot (straight line for power laws)",
  xaxis: %{title: "x", type: "log"},
  yaxis: %{title: "x²", type: "log"}
)
|> Plotly.show()