“Bruteforcing” spectra with Fullprof

One day I faced the following problem: to fit the diffraction pattern knowing initial lattice parameters and crystal system, however, exact space group was unknown.

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On physics…

Чтобы построить полную теорию, фактов всегда достаточно, не хватает только фантазии.
Д. Блохинцев

[There are always enough facts to build a complete theory, only fantasy is lacking.
D. Blokhintsev]

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Last evening had a nice chat with a friend of mine from the Materials Science Department.  At a certain point we  came to a discussion  about the crystal structure and  ways to  represent it.  As my counterpart was pointing out that it’s enough to give chemical composition and a space group to define the crystal structure, he stated that  Strukturbericht notation is superfluous and useless.

We had a long and interesting discussion, which I omit here. However, we came to an agreement that at least in the following phrase, using the Strukturbericht notation is good, as it gives the shortest and clearest explanation of what is going on:

Ni2MnAl exhibits structural transitions between  the L21B2A2 phases at 990 K and 1220 K, respectively.”

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Standalone LateX

A common approach for using images in latex documents is adding \usepackage{graphicx} to the preamble and of myfile.tex inserting image in the following text with \includegraphics{my_image.eps} ( the image type can be different including png, jpg and even .pdf).

If the image type is a some kind of mathematical graph or drawing/scheme one could use  TikZ or PSTricks to draw it. However, this approach results in “double work”,  e.g. even on a minor change one needs first to compile my_image.tex to my_image.eps, then recompile myfile.tex to update picture in the resulting pdf. Additionally this method has  drawbacks, such as changing font size of the text in on resizing the my_image.eps.

One of the possible ways to solve this problem is using standalone package. It allows inserting  my_image.tex file in a myfile.tex as an image, while keeping the possibility to compile  my_image.tex as a standalone image. Example file listings can be seen in a dedicated gists.

This text is mostly based on the following discussion on tex.stackexchange.

An explanatory remark

Currently I’m a PhD student, finishing my thesis. During the preparation of the manuscript I used LaTeX for the typesetting and git for the revision control.

I would like to share certain ideas and techniques which for the preparation of the manuscript and data visualization, so following posts of this blog will cover (but won’t be limited to) this topic. And I hope that this experience will be useful for anybody else.

Maxima testsuite benchmarks

Here are some execution time benchmarks of Maxima computer algebra system.

Maxima 5.29.1 was compiled with various Lisp compilers: CLISP, ECL and SBCL. For each case function  run_testsuite(display_all = true, time=all); was used for comparison of execution speed of Maxima with these compilers.

Benchmarks were run on Funtoo runnning 3.7.5-pf kernel on i7-2630QM CPU @ 2.00GHz 4Gb RAM. The system was running single shell without X,networking, etc.  No unexpected errors (there are tests resulting in error on technical purpose) were found out of 9,519 tests with each compiler. I show the timing results under the cut. Continue reading