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Precision (computer science)

Precision (computer science) is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Precision (computer science) rather than just read about it. In short: In computer science, the precision of a numerical quantity is a measure of the detail in which the quantity is expressed. This is usually measured in bits, but sometimes in decimal digits.

Key takeaways

  • Precision (computer science) belongs to computer science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Precision (computer science) to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Precision (computer science) from memory before moving on to harder problems.

Reference excerpt

In computer science, the precision of a numerical quantity is a measure of the detail in which the quantity is expressed. This is usually measured in bits, but sometimes in decimal digits. It is related to precision in mathematics, which describes the number of digits that are used to express a value. Some of the standardized floating-point precision formats are:

Half-precision floating-point format Single-precision floating-point format Double-precision floating-point format Quadruple-precision floating-point format Octuple-precision floating-point format Of these, octuple-precision format is rarely used. The names refer to the size of a computer word, commonly 32-bits on many current computer architectures. A single-precision value occupies one word, a half-precision half of a word, double-precision two words, etc. The single- and double-precision formats are most widely used and supported on nearly all platforms. The use of half-precision format and minifloat formats has been increasing especially in the field of machine learning since many machine learning algorithms are inherently error-tolerant.

Rounding errors

Precision is often the source of rounding errors in computation. The number of bits used to store a number will often cause some loss of accuracy. An example would be to store "sin(0.1)" in IEEE single-precision floating point standard. The error is then often magnified as subsequent computations are made using the data (although it can also be reduced).

See also Approximate computing Arbitrary-precision arithmetic Extended precision Granularity IEEE754 (IEEE floating point standard) Integer (computer science) Minifloat (8-bit and less) Significant figures Truncation

References

Worked examples

Example 1 — a first encounter with Precision (computer science)

Start with the simplest possible case. Write down what Precision (computer science) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Precision (computer science) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Precision (computer science) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Precision (computer science)

In research
Precision (computer science) appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Precision (computer science) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Precision (computer science) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Approximations, Computer data, so understanding it makes those chapters shorter.
In everyday life
Look for Precision (computer science) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Precision (computer science) in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Precision (computer science) means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Precision (computer science) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Precision (computer science) in simple terms?

In computer science, the precision of a numerical quantity is a measure of the detail in which the quantity is expressed. This is usually measured in bits, but sometimes in decimal digits.

Why does Precision (computer science) matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Precision (computer science)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Precision (computer science).

Tags

  • Approximations
  • Computer data

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