Miscellaneous articles, lessons ...
Une petite synthése sur le codage informatique des nombres, des formats utilisés ainsi que des conséquences du point de vue précision, algorytmique ....
This article is about numerical precision, algorithm choice and optimisation. The whole on the existential question of the best method of computing sin or cos function.
After writing a few lines of program, you probably faced with source codes containing small words difficult to understand. The few lines of this article discuss some useful aspects of these C and C++ identifiers/modifiers.
The C, C++: new, delete malloc and free commands use often complicated memory management mechanisms. A misuse of this management very often leads to the unexplained "crash" of a program. In this article, we will try to get a clearer view of this management as well as the management of Objects managed automatically or not by the compiler. You will find attached to this article a library (also available for download in the arduino download area) allowing you to experiment and may be more clear about it.
Note: this article is written in English AND French (two versions in the same file).
This article describes how to make a compiler of simple mathematical expressions using a computer grammar. It provides an overview of the tools used in such an operation. A fully executable version to compile for an arduino mega (written in C++) allows to understand the link between theory and practice. Finally it can be a good starting point for many improvements.
We are fed with curves, figures derived from sampled data often with a small asterisk (average of the sliding window). In the same way, on our mobile phones, we listen to averaged sampled sounds... In this article, we will try to demystify this asterisk and discuss under different aspects of sliding averages, their uses, the manipulations, as well as the programming of these averages.
This article proposes to explain without mathematical excesses what the Fourier transform is. It also approaches the "numerical calculation" aspect of this transform with a comparison of two calculation algorithms. Finally, in a C++ application designed for an arduino, it proposes an almost "real time" view-meter of the transform of a sound.
You will find a French and an English version of this article. As French is not my mother language, I apologize in advance for any translations that might disturb the citizens of its majesty. The captions of some illustrations could not be translated.