Matlab is a great programming language and environment because of its ease of use, great visualization, and rapid prototyping abilities. Matlab has a feature called MEX, Matlab Executables. See: Matlab MEX Introduction MEX files allow Matlab scripts to call user-supplied functions written in C/C++ and… Read more
Introduction Message Passing Interface (MPI) is a portable library of subprograms which can be used to facilitate parallel computing. The MPI subprograms can be called from C and Fortran programs. Parallel Computing Parallel computing enables large scale numerical problems to be solved in a timely… Read more
Here is a Fortran program which performs matrix inversion using the LU decomposition method: INVERSE_MATRIX.F It is compiled via: gfortran -o INVERSE_MATRIX INVERSE_MATRIX.F -llapack It compiles & runs under both Ubuntu & Cygwin. See also: http://www.nag.com/numeric/fl/nagdoc_fl23/examples/source/f07ajfe.f90 * * * The INVERSE_MATRIX.F program uses the subroutines:… Read more
Passing 1D array as function argument Example… // prototype function declaration void calc(double *x); double a[1000]; int main() { // call calc calc(a); } void calc(double *x) { // do some calculations } *************************************************************** Dynamic Memory Allocation for 1D Array int* a = NULL; //… Read more
This is another matrix multiplication project using the BLAS function dgemm. It is complied and run in an Ubuntu system. The set consists of two programs: (right mouse click. save target or link as) matrix_mult_cf.cpp fort_matmul_main.f The set calculates: C = A*B The C++ program… Read more
MinGW stands for Minimalist GNU for Windows. MinGW is a native software port of the GNU Compiler Collection (GCC) and GNU Binutils for use in the development of native Microsoft Windows applications. MinGW can be downloaded with Code::Blocks. Or it can be downloaded via soureforge.… Read more
The following program reads a 2D array of numbers. The array may have an arbitrary or unknown number of rows and columns up to a certain cell limit. The program counts the number of columns and rows as it reads the data. The program souce… Read more
Here is a program that uses dgemm to multiply two matrices: matrix_mult.cpp The dgemm function is implemented using gsl blas. It can be compiled under Cygwin as: gcc -o matrix_mult_alt matrix_mult_alt.cpp -lgsl -lstdc++ And under Ubuntu as: gcc -o matrix_mult_alt matrix_mult_alt.cpp -lgsl -lgslcblas -lstdc++ *… Read more
Blas and Lapack may be installed on an Ubuntu system using the instructions at: Generalized Eigenvalue Problem * * * C++ programs that use Lapack can be compiled in Terminal or Bash shell mode via: g++ file_in -o file_out -lgfortran -llapack -lm where file_in is… Read more
The goal of this project is to solve a “very large” generalized eigenvalue problem in a “reasonable” amount of time using library functions. The mass and stiffness matrices may be either dense or sparse. Optimum routines are desired for each case. Here is description of… Read more