MPI programs are more difficult to debug than other programs because of their parallel nature. The MPI programming model follows the single program multiple data paradigm or the multiple program multiple data paradigm. Debugging MPI programs is complicated by the following characteristics: Several processes run in parallel in a coordinated way. These processes may all… Continue reading MPI debugging
Modern digital system cameras and also some digital compact cameras allow to create and to store images in a so-called raw format. A raw image contains the minimally pre-processed sensor data, meta-data about the picture such as camera model, lens model and camera settings under which the picture has been taken and possibly a fully… Continue reading From numbers to images – Raw image processing with Python
In C++11 we got range-based for loops which allow one to iterate over the elements of a container easily. In some situations, however, having sequential access to each element of the container is not sufficient for the task that shall be done in the loop body. Commonly an additional counting index is required. In this… Continue reading Range-based for loops with counters
FizzBuzz is a popular test that is commonly used in job interviews for software developers. In this test one is asked to write a function that prints the numbers from 1 to 100. But for multiples of three “Fizz” has to be printed instead of the number and for the multiples of five the word… Continue reading FizzBuzz or the beauty of compile-time calculations in C++17
The R programming language has gained some popularity in recent years. It is widely used for developing statistical software and data analysis but also for Monte Carlo simulations. Such Monte Carlo simulations require high-quality (pseudo) random numbers. Roland Schmid and Riccardo Porreca of Mirai Solutions have written an R package providing access to the TRNG… Continue reading R as random
Floating-point exceptions During a numerical calculation various kinds of run-time errors may occur. In C++, such an error may be indicated via floating-point exceptions or via the (global but thread-local) variable errno. Floating-point exceptions are completely unrelated to C++ exceptions. When an floating-point exception is raised by an erroneous operation, the exception is simply noted… Continue reading C++11/14 for scientific computing VI
The Intel Math Kernel Library (MKL) contains a collection of highly optimized numerical functions. Among others, it provides implementations of Blas functions and Lapack functions for various linear algebra problems. A program, which is dynamically linked against the standard Blas and Lapack libraries, can easily benefit from alternative optimized implementations by replacing libblas.so and liblapack.so… Continue reading Boosting NumPy with MKL
Some programming languages have functions with named parameters. Named parameters let the programmer pass the parameters to a function in any order and they are distinguished by a name. So the programmer can explicitly pass all the needed parameters and default values without worrying about the order used in the function declaration. In C++, however,… Continue reading Revisiting the named parameter idiom in C++14
A new version of TRNG (Tina’s Random Number Generator Library) has been released. TRNG may be utilized in sequential as well as in parallel Monte Carlo simulations. It does not depend on a specific parallelization technique, e.g., POSIX threads, MPI and others. The new version 4.18 is a bug-fix and maintenance release and can be… Continue reading New TRNG release
In earlier posts I gave an introduction to the Message Passing Library (MPL). With MPL processes can send and receive messages with data of different data types. What kind of data types are supported by MPL? MPL supports the same kinds of elementary data types as MPI does. These are: the integer types char, short… Continue reading MPL – Data types