computer science

Renjin

Renjin 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 Renjin rather than just read about it. In short: Renjin is an implementation of the R programming language atop the Java Virtual Machine. It is free software released under the GPL.

Key takeaways

Renjin 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 Renjin to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Renjin from memory before moving on to harder problems.

Reference excerpt

Renjin is an implementation of the R programming language atop the Java Virtual Machine. It is free software released under the GPL. Renjin is tightly integrated with Java to allow the embedding of the interpreter into any Java application with full two-way access between the Java and R code. Renjin's development is primarily supported by BeDataDriven, but ultimately made possible by several current and past contributors, including Mehmet Hakan Satman, Hannes Mühleisen, and Ruslan Shevchenko.

History Renjin's roots lie in an abortive 2010 attempt to compile the GNU R interpreter for the JVM via nestedvm, a toolchain which involves cross-compiling C and Fortran code to a static MIPS binary, which nestedvm can then translate to JVM bytecode. This proved challenging as GNU R had grown to rely heavily on dynamic linking and the best C standard library implementation available at the time for the MIPS architecture, Newlib, was not fully compatible with the GNU C Library, against which GNU R had been developed. The experience with the R4JVM project provided the BeDataDriven team with in depth look at the GNU R codebase, and convinced them that a new implementation, written in Java, was a feasible undertaking. Development on Renjin began in October 2010, and rapidly resulted in a functional, if minimal, interpreter for the R language.

References

External links Official website

Worked examples

Example 1 — a first encounter with Renjin

Start with the simplest possible case. Write down what Renjin 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 Renjin 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 Renjin 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 Renjin

In research: Renjin 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 Renjin 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: Renjin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Array programming languages, Cross-platform free software, Data-centric programming languages, so understanding it makes those chapters shorter.
In everyday life: Look for Renjin 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 Renjin in 20 minutes

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

Frequently asked questions

What is Renjin in simple terms?

Renjin is an implementation of the R programming language atop the Java Virtual Machine. It is free software released under the GPL.

Why does Renjin 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 Renjin?

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 Renjin.