ELI5: Explain Like I'm 5

Matrix chain multiplication

Okay kiddo, imagine you have a big box filled with smaller boxes. Each of these smaller boxes has some numbers written on it, and we want to multiply all the numbers in each of these boxes together. Now, we can't just start multiplying these boxes all willy-nilly. We need to figure out the best way to do it so that we use the least amount of energy.

That's where matrix chain multiplication comes in. See, these boxes are actually matrices (which is just a fancy word for a grid of numbers). And we want to find the most efficient way to multiply all these matrices together.

So let's say we have 4 matrices: A, B, C, and D. We could just start multiplying them in any order we want, like (A*B)*(C*D), or (A*B*C)*D. But some ways of multiplying them will take more energy than others, because we have to do more calculations.

That's where an algorithm comes in. An algorithm is like a set of instructions that a computer can follow to solve a problem. We can use an algorithm to figure out the most efficient way to multiply these matrices together.

The algorithm for matrix chain multiplication is called the Matrix Chain Multiplication (MCM) algorithm. It tells us to break down the problem into smaller sub-problems, and to solve those sub-problems first before combining them to solve the larger problem.

In our case, we can break down the problem of multiplying (A*B*C*D) into the sub-problems of multiplying (A*B), (B*C), and (C*D). We solve each of these sub-problems using the MCM algorithm, and then combine the results to get the final answer.

By using the MCM algorithm, we can find the most efficient way to multiply all these matrices together. This can save us a lot of energy, especially if we're dealing with a lot of matrices. And that's how matrix chain multiplication works, kiddo!
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