# Grok all the things

grok (v): to understand (something) intuitively.

# Artificial Neural Networks

ðŸ™„ Â Cynics & grumps

Ah, Artificial Neural Networks (ANNs). The magical buzzword that promises to solve all our problems and bring about a utopia where machines can think just like humans. Well, hold on to your hats, folks, because we're about to dive into the world of ANNs and see what they're really all about.

First, let's clear the air: ANNs are not some magical, sentient being that can mimic the human brain. They are just a mathematical model â€“ a bunch of linear algebra and calculus â€“ that tries to approximate functions. That's it. A glorified curve-fitting machine. But hey, amidst the hype, they do have their merits.

ANNs are loosely inspired by the human brain â€“ because, of course, humans love to make everything about themselves. We've got layers of interconnected nodes (neurons), and each node takes inputs, does some math, and fires off an output. There's a whole lot of multiplying, summing, and applying activation functions, like the ever-popular ReLU (Rectified Linear Unit) or sigmoid. And let's not forget the backpropagation algorithm, which is just a fancy way of saying, "we messed up, let's go back and fix our mistakes."

``````import numpy as np

def sigmoid(x):
return 1 / (1 + np.exp(-x))

def sigmoid_derivative(x):
return sigmoid(x) * (1 - sigmoid(x))
``````

Here's the kicker, though: ANNs have been around since the 1940s. That's right; this "cutting-edge" technology is older than the first moon landing. It's just that they've only recently become trendy, thanks to the ever-growing deluge of data and the insatiable hunger for machine learning solutions.

But let's step back for a moment. What are ANNs even good for? Well, they can be used for classification, regression, and even generating new data â€“ all while masquerading as "thinking" like a human brain. In reality, though, they're just really good at finding patterns in the data and making predictions based on those patterns.

Now, you might be thinking, "That sounds pretty useful!" And you're right; it is. But here's the thing: ANNs are not a one-size-fits-all solution. They can be finicky, requiring a meticulous balance of hyperparameters, like learning rate, number of layers, and number of nodes. Too few layers, and you've got an underfitted model; too many, and you're overfitting like there's no tomorrow. It's a delicate dance that can leave even the most seasoned data scientist pulling their hair out.

``````import keras
from keras.models import Sequential
from keras.layers import Dense

ann_model = Sequential()