Friday, August 6, 2021

Why Dredd Blog Uses C++

Bjarne Stroustrup
1) A Dredd Blog reader is working on software infrastructure which is, among other things, the international standard for Oceanography (Wikipedia). 

2) The C++ version of the software library is available for download at no cost at here.

Here are other reasons: 

"1. Introduction

Computation has become a central tool in economics. From the solution of dynamic equilibrium models in macroeconomics or industrial organization, to the characterization of equilibria in game theory, or in estimation by simulation, economists spend a considerable amount of their time coding and running fairly sophisticated software.

And while some effort has been focused on the comparison of different algorithms for the solution of common problems in economics (see, for instance, Aruoba, Fernandez-Villaverde, and Rubio-RamÌrez, 2006), there has been little formal comparison of programming languages.

This is surprising because there is an ever-growing variety of programming languages and economists are often puzzled about which language is best suited to their needs.

Instead of a suite of benchmarks, researchers must rely on personal experimentations or on folk wisdom.

For example, it is still commonly believed that Fortran is the fastest available language or that C++ is too hard to learn.
...
In section 4, we report speed results for each language (including several implementations of the same language and different compilers), but here is a brief summary of some of our main Findings: 

'1. C++ and Fortran are still considerably faster than any other alternative, although one needs to be careful with the choice of compiler.

2. C++ compilers have advanced enough that, contrary to the situation in the 1990s and some folk wisdom, C++ code runs slightly faster (5-7 percent) than Fortran code.'"  

(A Comparison of Programming Languages in Economics, PDF; cf. A Comparison of Programming Languages, not PDF).

Posts here on Dredd Blog have shown that using the international standard is not just for scientific organizations (Build Your Own Thermosteric Computational System, 2; The World According To Measurements, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26).

Just because C++ is the fastest, doesn't mean it is the most difficult to use (see video below if you are a beginner).



Monday, August 2, 2021

Seaports With Sea Level Change - 16

Talk Talk
The Permanent Service for Mean Sea Level (PSMSL) keeps records of sea level change (SLC) around the world.

Today's post is an update of their latest data (July 19, 2021).

The previous post in this series detailed seaports and sea level changes there.

Today's post is limited to the sea level changes (sea level rise and fall) that are clearly taking place along the coastlines of the many nations where those seaports are now located.

The previous post covered this issue too (Seaports With Sea Level Change - 15), but I thought I would update that post with more recent PSMSL data.

For those who do not frequent Dredd Blog posts, and who still entertain the idea of the oceans being like a "bathtub" in the sense of having a uniform sea level, I will provide some links with contrary revelations.

As professor Jerry Mitrovica said, "nothing could be further from the truth."

Obviously sea level rises and falls before our very eyes every day in the form of high and low tide (bathtubs don't do that do they?).

The graphs show that some areas have varying degrees of sea level rise while other areas have varying degrees of sea level fall (Appendix: A-C, Appendix: D-G, Appendix: H-L, Appendix: M-O, Appendix: P-T, Appendix: U-Z).

I am not talking about tides, which they also have, I am talking about long range rising and falling of sea level.

This is caused by the melting of the Cryosphere in areas near the oceans.

Those areas such as Greenland, Antarctica, and Glacier Bay (Alaska) have sufficient mass and gravity to pull the ocean toward them, thereby raising the ocean level there.

As those areas melt, their mass and gravity diminishes so they lose their hold on that water, and it flows away from them causing sea level fall there and sea level rise elsewhere (The Bathtub Model Doesn't Hold Water, 2, 3).

Plus, thermal expansion is not 'the' or 'a' major cause of sea level change (The Young Old Sea Level Change Hoax). 

And finally, the sea level change estimates in general have been based on inaccurate ground level data (Global vulnerability to sea level rise worse than previously understood) not to mention 'the wobble' (A 'wobble' in the moon's orbit could result in record flooding).

So, check out the video below (a presentation by Professor Mitrovica).

The previous post in this series is here.




Appendix SLC P-T

 This is an appendix to: Seaports With Sea Level Change - 16























 

Appendix SLC M-O

 This is an appendix to: Seaports With Sea Level Change - 16












 

Appendix SLC H-L

This is an appendix to: Seaports With Sea Level Change - 16