Subplot for multiple panels in MATLAB - Time & Space Complexity

Time Complexity: Subplot for multiple panels

O(n)

Understanding Time Complexity

When creating multiple plots in MATLAB using subplots, it is important to understand how the time to draw these plots grows as the number of panels increases.

We want to know how the total work changes when we add more subplot panels.

Scenario Under Consideration

Analyze the time complexity of the following MATLAB code that creates multiple subplot panels.

for i = 1:n
    subplot(1, n, i);
    plot(rand(1, 100));
end
    

This code creates n subplot panels arranged in a 1-by-n grid and plots random data in each panel.

Identify Repeating Operations

Look at what repeats in the code.

• Primary operation: The for loop runs n times, creating and plotting in each subplot.
• How many times: Each plotting operation happens once per subplot, so n times total.

How Execution Grows With Input

As you increase the number of subplots, the total work grows roughly in direct proportion.

Input Size (n)	Approx. Operations
10	10 plotting calls
100	100 plotting calls
1000	1000 plotting calls

Pattern observation: Doubling the number of subplots roughly doubles the total work.

Final Time Complexity

Time Complexity: O(n)

This means the time to create and plot all subplots grows linearly with the number of panels.

Common Mistake

[X] Wrong: "Adding more subplots does not affect the total time much because each plot is small."

[OK] Correct: Each subplot requires separate plotting work, so more panels add up and increase total time linearly.

Interview Connect

Understanding how plotting multiple panels scales helps you write efficient visualization code and explain performance in real projects.

Self-Check

What if we changed the plotting data size from 100 points to 1000 points per subplot? How would the time complexity change?