armadillo

I fiddled with this the whole day, so I thought I might make everyone benefit from my experience, please see my answer below. I first had a problem with running a compiled Mex file within Matlab, because Matlab complained that it couldn't open the shared library libarmadillo . I solved this using the environment variables LD_LIBRARY_PATH and LD_RUN_PATH ( DYLD_LIBRARY_PATH and LYLD_RUN_PATH in osx). The problem remained however, that a simple test file would segfault at runtime even though the exact same code would compile and run fine outside Matlab (not Mex'd). The segfault seems to be

I am trying to use the Armadillo matrix library to do matrix calcualtions and it needs BLAS and LAPACK. The Armadillo documentation recommended getting the precompiled versions from http://www.stanford.edu/~vkl/code/libs.html There are .lib and .dll files in there. The only problem is I don't know how to get Visual Studio (Express Edition 2008) to recognize these files. I try to copy them to the Visual C++ include and lib directories C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\include\ and C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\lib\ , but it doesn't seem to do anything

I am building an image processing application using OpenCV. I am also using the Armadillo library because it has some very neat matrix related functions. The thing is though, in order to use Armadillo functions on cv::Mat I need frequent conversions from cv::Mat to arma::Mat . To accomplish this I convert the cv::Mat to an arma::Mat using a function like this arma::Mat cvMat2armaMat(cv::Mat M) { copy cv::Mat data to a arma::Mat return arma::Mat } Is there a more efficient way of doing this? To avoid or reduce copying, you can access the memory used by Armadillo matrices via the .memptr()

The problem is that I have a variable arma::mat prob_vec and want something equivalent to rmultinom(1, 1, prob_vec) in R. I found the rmultinom function provided by RcppArmadillo has a weird argument requirement which is different from that in R! So it won't pass the compilation. I just wanna know how to draw the desired sample in RcppArmadillo, or equivalently in Armadillo. If I need to get the pointer or convert my prob_vec variable, please tell me how. Many thanks! Dirk Eddelbuettel Your friendly neighbourhood co-author of RcppArmadillo here: I can assure you that it does not provide

In a Python extension module I've written in C++, I use the following snippet of code to convert a NumPy array into an Armadillo array for use in the C++ portion of the code: static arma::mat convertPyArrayToArma(PyArrayObject* pyarr, int nrows, int ncols) { // Check if the dimensions are what I expect. if (!checkPyArrayDimensions(pyarr, nrows, ncols)) throw WrongDimensions(); const std::vector<int> dims = getPyArrayDimensions(pyarr); // Gets the dimensions using the API PyArray_Descr* reqDescr = PyArray_DescrFromType(NPY_DOUBLE); if (reqDescr == NULL) throw std::bad_alloc(); // Convert the