Skip to content

Latest commit

 

History

History
190 lines (113 loc) · 18.9 KB

File metadata and controls

190 lines (113 loc) · 18.9 KB

The Essentials of Precision and Quantization Made Easy

img.png

Ever think about how space rockets work, why songs on your phone sound so clear, or if your laptop can run smart AI programs? Well, you might have bumped into two big ideas without even knowing it: precision and making things simpler, or "quantization." Let's talk about why these ideas are super important when we use technology.

Different Types of Numbers

But first, you need to know about numbers. Numbers are everywhere in math and science. They come in different types, some of them you must be familiar with, the others you might not have heard of before. Let's take a look at them.

  1. Integer: Whole numbers like 1, 2, or 3 are called integers. These are the basic numbers with no fractional or decimal parts. They can be positive, negative, or zero. Examples include -3, 0, 7. In programming, 'integer' typically refers to a data type that represents these whole numbers.

  2. Real Numbers: In mathematics, real numbers include all the numbers on the continuous number line. This includes both rational numbers (like 1/2, which can be expressed as a fraction) and irrational numbers (like √2, which can't be accurately expressed as a simple fraction).

The term 'rational' is derived from the concept of a ratio. A rational number is one that can be represented as the ratio of two integers. For example, 1/2 is a rational number because it represents the ratio of 1 to 2. Conversely, an irrational number is a number that cannot be expressed as the ratio of two integers. For instance, √2 is an irrational number as it does not have a simple fractional representation.

In the Japanese language, these terms are translated as 'ゆうりすう(有理數)' for 'rational number' and 'むりすう(無理數)' for 'irrational number'. The word '有理' implies 'reasonable', while '無理' suggests 'unreasonable'. Thus, in a rather amusing twist, '有理數' (rational numbers) are deemed 'reasonable numbers', and '無理數' (irrational numbers) are seen as 'unreasonable numbers'. Koreans also use the terms '유리수(有理數)' and '무리수(無理數)', sometimes without really thinking about why. This linguistic quirk is a vestige of Koreans adopting these mathematical concepts from Japan. Moreover, China, Japan, and Korea share the same Chinese character system, which adds a layer of complexity to the terminology. In Chinese, '有理數' is 'yǒulǐshù', and '無理數' is 'wúlǐshù'.

This translation has often led to confusion among many Koreans and Japanese. To clarify, '無理數' refers to 'irrational numbers' and '有理數' to 'rational numbers'. It's important to remember that rationality in this context has nothing to do with being reasonable; it's about a number's ability to be expressed as a ratio of two integers.

  1. Float and Double: These terms come from programming and represent numbers with fractional parts. The difference between them is in their precision and the amount of memory they use. A 'float' is a single-precision floating-point number, and a 'double' is a double-precision floating-point number. Double has more digits and is more accurate than float.

You may have heard of the term 'FLOPS' thrown around in the media. "FLOPS" stands for Floating Point Operations Per Second, and it's a measure used to quantify the performance of a computer or a processor. These are arithmetic calculations involving numbers with fractional parts: floating-point numbers. Examples include multiplying 3.14 (a float) by 2.56 (another float) or dividing 5.678 by 3.21. These operations are more complex and resource-intensive than integer operations.

FLOPS measures how many of these operations a computer can perform in one second. It's a speed measure.

In fields like scientific computing, engineering simulations, weather forecasting, or any area that requires a lot of calculations with real numbers, the ability to perform many floating-point operations quickly is crucial.

FLOPS is typically used to measure the performance of supercomputers, servers, and high-performance computing systems. It's also relevant in the context of graphics processing units (GPUs) used for gaming, 3D rendering, and deep learning.

Here's how FLOPS are usually quantified:

  • Kiloflops (KFLOPS): Thousands of FLOPS.
  • Megaflops (MFLOPS): Millions of FLOPS.
  • Gigaflops (GFLOPS): Billions of FLOPS.
  • Teraflops (TFLOPS): Trillions of FLOPS.
  • Petaflops (PFLOPS): Quadrillions of FLOPS.
  • Exaflops (EFLOPS): Quintillions of FLOPS.

The higher the FLOPS rating, the more powerful the processor is in handling complex calculations involving floating-point numbers.

The U.S. government recently restricted the export of NVIDIA's and AMD's advanced AI chips, including GPUs, to certain countries, notably China and some Middle Eastern nations. The export ban particularly targets high-end GPUs, which are crucial for the development of generative AI systems like large language models. The restrictions aim to prevent the sale of AI chips that exceed a certain performance threshold measured in FLOPS per square millimeter. To cope with these restrictions, NVIDIA developed pared-back versions of its latest GPUs.

  1. Complex Numbers: These are numbers that include a real part and an imaginary part. They are usually written in the form a + bi, where 'a' is the real part, 'b' is the imaginary part, and 'i' is the square root of -1. Complex numbers are useful in advanced mathematics and engineering fields, particularly when dealing with waves and oscillations.

Each type has its specific use, depending on what you want to represent or calculate.

Numbers in Python

Here are Python examples for each type of number:

  1. Integer:

    integer_example = 5
    print(integer_example)
  2. Real Numbers (represented as float in Python):

    real_number_example = 3.14159
    print(real_number_example)
  3. Float:

    float_example = 0.123
    print(float_example)

    float_example here is a floating-point number, which in Python, is the default type for any number with a decimal.

  4. Double: Python doesn't have a separate double type as it treats float and double similarly. Both are represented as float with double precision.

  5. Complex Numbers:

    complex_example = 2 + 3j
    print(complex_example)

    In Python, complex numbers are defined using the j or J suffix to denote the imaginary part.

Each example shows how to declare these types in Python and print them out. Remember, Python is dynamically typed, so you don't need to explicitly define the type of a variable like in some other languages. If you happen to see what C programmers have to do even for simple things like printing a number, you'll appreciate Python's simplicity.

In C:

#include <stdio.h>

int main() {
    int number = 10;
    printf("The number is %d\n", number);
    return 0;
}

In Python:

number = 10
print(f"The number is {number}")

But appearances can be deceiving. Python is a high-level language that hides a lot of complexity under the hood, but slow performance is the price you pay for this convenience: C is much faster than Python. In fact, many high-performance computing frameworks, including NumPy, PyTorch, and MLX, are indeed written in C or C++ for reasons.

When Rockets Fail: It's All About Being Exact

Launching rockets is really tricky, and getting the numbers right is what makes them fly properly or blow up. They're put together with really exact science and math. A little mistake in the numbers can make a rocket go the wrong way or even explode. Like how the Challenger space shuttle accident in 1986 happened. I am old enough to have witnessed that on TV. It wasn't a math error, but it shows that not being careful with small details, like how cold affects rubber parts, can lead to big problems.

Precision in numbers, such as the value of Pi, is paramount in programming. For instance, while some might simply use 3.14, others might extend it to 3.14159. The exactness of this number in your code could be critical, potentially the difference between success and failure in sensitive applications like rocket launches. It's crucial to handle numbers with utmost accuracy.

dtype = torch.float32
dtype = mx.float32

When working with numerical data in programming, it's crucial to define the type of numbers we'll be dealing with. This is where dtype comes into play in libraries like PyTorch and MLX.

dtype = torch.float32 in PyTorch and dtype = mx.float32 in MLX both specify that the numbers we are working with are floating-point numbers. As previously explained, floating-point numbers are numbers with decimal points, allowing for the representation of fractions or decimals, not just whole numbers.

The float32 part refers to the precision of these floating-point numbers. Specifically, it means that 32 bits of memory are used to store each number. This amount of memory allows for a balance between the range of values that can be represented and the precision (or accuracy) of these values.

In simpler terms, using dtype = torch.float32 or dtype = mx.float32 is like telling the computer, "We're going to work with numbers that have decimal points, and we need a reasonable level of precision for these numbers." This is particularly important in calculations where the exactness of decimal values matters, such as in scientific computing or machine learning algorithms.

You might imagine that float16 is less precise than float32, and float64 is more precise than float32. This precision comes at a cost: higher precision numbers consume more memory.

This concept gives you a sense of quantization, right? By adjusting the precision of numbers, you can make them more compact and quicker to process: float16 takes up less space than float32, and float32 uses less space than float64.

Now you basically know what all those quantized models mean and in what bits they are stored. For example, a quantized model with 8 bits means that the model is stored in 8 bits. The lower the number of bits, the smaller the model size, and the faster the model runs. But the lower the number of bits, the less accurate the model is. So it's a trade-off between speed and accuracy.

In order to make models to run on low-end computers with limited memory and processing power, even integer models can be created. These models use integers (whole numbers) instead of floating-point numbers. Through quantization, the weights and sometimes the activations of a model from floating-point numbers (like float32) can be converted to integers. Quantization reduces the model size and can significantly speed up inference while using less power. This is essential for deploying models on low-end devices.

Digital Music: Keeping the Human Touch

onemanband.png

I play in a one-man band just for fun, using guitars, bass, keyboards, and drums, making tons of mistakes. But I just keep recording, knowing that I can fix them later with quantization in Logic Pro X.

Quantization in making music is like snapping your notes onto a beat grid, so they're perfectly in time. It's super useful for cleaning up the little timing mistakes that might happen when someone's jamming out on an instrument. But here's the thing – if you go overboard with it, your music could end up sounding like a robot’s playing it and lose that cool, human touch that a real-life drummer brings.

drums.png

Now, you might think quantizing stuff in music has nothing to do with what tech geeks talk about in machine learning. But actually, it's a pretty similar deal. In both worlds, quantizing means you're taking something that can be super precise with lots of in-between values and boiling it down to simpler, chunkier bits. Like, imagine you've got all the numbers from 1 to 2 – in the land of whole numbers, it's just 1 and 2, that's your lot. But if we're talking about the more detailed floating-point numbers, there's a whole universe of numbers we could pick. Quantization’s about ditching that endless sea of options and sticking to the essentials, whether that's making music time perfectly or helping computers do math stuff without breaking a sweat.

In this context, let's take a look at some other quantization examples you might have heard of. The concept of quantization, in the sense of converting continuous information into discrete units, is applied in various fields beyond machine learning and music production.

  1. Digital Imaging: In digital photography and image processing, quantization refers to the process of converting the continuous range of color tones and brightness levels in an image into a finite number of discrete levels. This is essential in digital imaging because computers can only handle discrete values. For example, an 8-bit color depth can represent 256 discrete levels of red, green, and blue.

  2. Signal Processing: In the field of signal processing, quantization is used to convert continuous analog signals into discrete digital signals. This is a critical step in analog-to-digital conversion, where continuous signals (like sound or radio waves) are converted into a format that digital systems can process and analyze.

  3. Quantum Computing: In quantum computing, the term 'quantum' itself implies the fundamental nature of quantization. Here, information is represented using quantum bits or qubits, which, unlike classical binary bits, can exist in a superposition of states (0 and 1 simultaneously), but when measured, they give a discrete outcome (either 0 or 1).

  4. Telecommunications: In digital communication systems, quantization is used when encoding analog signals into digital signals for transmission. The continuous amplitude of the analog signal is quantized into a set of discrete levels for efficient digital representation and transmission.

  5. Economics and Finance: In these fields, quantization can refer to the discretization of continuous financial data for modeling or analysis purposes. For example, stock prices, which fluctuate continuously over time, can be quantized into discrete time intervals for analysis, like daily closing prices.

  6. Medical Imaging: Techniques like MRI or CT scans involve quantization. These scans measure physical properties in a continuous space but ultimately represent these measurements in a discrete digital image composed of pixels, each with a quantized value representing different aspects of the tissue being imaged.

In all these examples, the core concept of quantization is consistent: it involves the conversion of a continuous spectrum of values into a discrete set, facilitating easier processing, analysis, storage, or transmission in a digital format.

Continuous means infinite, and discrete means finite. Continuous values can take on any value within a range, while discrete values can only take on specific values within a range. That's the gist of simplifying things by quantizing them.

In statistics, which is another essential area for AI, or darn happier life in general, understanding the concept of continuous and discrete values is crucial.

Now you understand why I place such strong emphasis on the four pillars of object orientation. Every darn thing is an object. Every darn thing can be inherited. Every darn thing can exhibit polymorphism. Every darn thing can be encapsulated.

Object-Orientation-Made-Easy.md

Digital vs. Analog

Can you define what digital and analog mean? You might have thought you knew, but if you do, define them using your own own words, without looking them up.

In the digital world, we often need to represent real-world, analog data in a form that computers can understand and process. Analog data is continuous by nature, meaning it can take any value within a given range. For example, the temperature in a room can be 20.1, 20.15, 20.151, and so on.

To digitally represent this continuous data, we use quantization. This process involves converting the infinite possibilities of continuous data into a finite set of discrete values. Using the temperature example, if we quantize it to whole numbers, 20.1 and 20.9 would both be represented as 20 in digital form.

This conversion is crucial because digital systems, like computers, operate on discrete data. By quantizing, we transform continuous, analog signals into a digital format that can be easily stored, processed, and transmitted by digital systems.

So, quantizing in digital music probably sounds a lot more relatable now, huh?

Your music tracks are digital, which means they’ve been quantized. We constantly hear about high-definition audio and video. Yet, despite the hype, all these formats are quantized; none are truly continuous. This is precisely why die-hard enthusiasts argue they're a notch below the genuine, pure analog experience. It's also why vinyl records are making a comeback. They're analog, meaning they present sound continuously, without quantization—unlike digital formats, they're the 'real deal' to many.

However, this viewpoint isn't entirely accurate, considering that much of the music is initially recorded using digital technology, and the vinyl simply serves as a means to store these digital recordings. Plus, the playback equipment could be digital as well. If we're talking about experiencing music in its most authentic analog form, attending a live performance is the way to go. But it's interesting to note that even then, the sound waves are ultimately 'quantized' by your ears and brain. You can't hear beyond the range of human hearing or see beyond the range of human vision. All these sensations are quantized by your body. Thus, it all comes down to the degree of quantization.

The main takeaway is that quantization is a crucial concept when discussing digital systems that take samples from the real world.

Honestly, I could nerd out and dive way deeper into this topic, but then we'd be here all day, and I've probably lost you already. When you've got a sec, ponder why I specifically said 'taking samples from the real world.' It's a stats game, my friend—from analog to digital and back again. The act of taking samples means we are skipping some data points, which is a form of quantization. Consequently, the resulting data is discrete, not continuous.

In Summary

Precision and quantization are two sides of the same coin. They exist in a complex dance, intersecting at the heart of modern technological challenges and innovations. Whether it be the spectacular display of a rocket as it cleaves through the atmosphere, the rhythmic heart of electronic music, or the subtle reasoning of AI, both precision and quantization need to be carefully managed to achieve both functionality and artistry. They give us the ability to touch the stars, to move to an electrical beat, and to witness the birth of intelligence in our machines. Understanding and mastering these concepts allows us to push boundaries, innovate, and turn impossibilities into realities.