The CPU usage of R

As my computer is dual core, I supposed R should run must faster than it used to. However, not really. Nowadays I’m in Hershey using their four-core computer in the lab. What I found out is that no matter how many cores you have, R only uses one core, for which it has full usage.

However, if you open another R gui, it will use another core. So what you can do to get your computation fast is multi-task at the same time. Sounds like life, right? If you really focus on one thing, it turns out there always exists a limit, however, you can make it more efficient by being eclectic.

Dropbox in dualboot system computer

Today I have my computer fixed. It is a good new version with dualboot system: windows xp and ubuntu 10.04. Quite neat! Windows xp remains the same: slow boot-up, familiar software, and convenient entertainment tools. Ubuntu comes like a charm: fast booting (So fast), easy-going operation, and still difficult start-up  (But after you got everything done, you probably will enjoy everything).

The small trick for today is about Dropbox. As I have Dropbox in both Windows and Linux, the Dropbox folders for them are different since we could not rename the folders by ourselves (“Dropbox” in Linux and “My Dropbox” in Windows). This is kind of bothering me as the fact that I couldn’t sync them. 

After searching on the internet, the discussion here gives me a pretty easy way to fix it.  Download the little tool to change the Dropbox path.  Download.  It works like a charm!

Software installation in Ubuntu

I ran into the software installation on a desktop of Ubuntu. It’s  a lot of fun, (good), but time-consuming. As simple as it could be.  The Ubuntu is kind of like Iphone apps: hard start, easy addicted.

For statistical softwares: Matlab, R, vim-r-plugin.

For fMRI research: FSL, MRIcron, ITK-SNAP.

For word processor: Gnote, Texlive.

The convenient way to copy and paste in Ubuntu is highlight the text, press the middle button of mouse (wheel), and paste it by clicking the middle button again.  This saves a lot of time since sometimes CTRL+SHIFT+V could not update immediately after you copy in Ubuntu.

Subjunctive Noun Clauses

From book: Writing Academic English, by Alice Oshima and Ann Hogue.

After certain independent clause verbs and adjectives, you must use the subjunctive form of the verb in the following noun clause. The subjunctive form of a verb is the same as the base form.

The verbs and adjectives that require the subjunctive form in the noun clauses that follow indicate urgency, advisability, necessity, and desirability.

Verbs

advise, ask, command, demand, direct, insist, order, prefer, propose, recommend, request, require, suggest, urge

Adjectives

advisable, desirable, essential, important, mandatory, necessary, urgent, vital

It is necessary that students be on time for the final exam.

Make a subjunctive verb negative by putting the word “not” in front of it

She insisted that the company not lose any more customers to its competitors.

The subjunctive also occurs when the independent clause verb is in the passive voice.

It was recommended that the department not hire new staff at this time.

Reading notes

Today’s book:  Writing Academic English, by Alice Oshima and Ann Hogue.

• We mark a paragraph by indenting the first word about a half inch (five spaces on a typewriter or computer) from the left margin.
• All paragraphs have a topic sentence and supporting sentences.
• A topic sentence has two essential parts: the topic and the controlling idea.
• There are several kinds of supporting details: examples, statistics, and quotations.

Review:

1. A good topic sentences
   • is a complete sentence with a subject, a verb, and a controlling idea.
   • is neither too general nor too specific. It clearly states the main idea of the paragraph but does not include specific details.
   • is usually the first sentence in the paragraph.
2. Good supporting sentences
   • explain or prove the topic sentence.
   • are specific and factual.
   • can be examples, statistics, or quotations.
3. A good concluding sentence
   • signals the end of paragraph.
   • summarizes the important points briefly or restates the topic sentence in different words.

The equations in the Latex

For the imaginary part “i”, what I’m using is to make it as Roman format, which can be distinguished from the index “i”.

\newcommand{\ii}{{\rm i}}

At the same time, use Roman “r” to denote the radian. (Not sure that this is the correct form)

\newcommand{\rr}{{\rm r}}

Beamer Theme “Rochester”

When I use the beamer to get the presentation slides in pdf, I choose the theme “Rochester” due to its clean structure. However, adding the page number is the important for audience to quote and also for presenter to organize. Here’s one line I added for showing the page number in each slide.

Hello!

This is the studying record on R and LaTex, or even the webpage maintenance.