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Lagrange interpolation over a larger set of data
Hi all. I have a Lagrange program that uses a 4-point data set to interpolate some non-tabulated value in between any of those data points. I want to extend this script to act on a large input file, call it file1.dat, where the data is arranged in two columns Xin Yin. Then the script should... -
solving linear system with zero rows(picking rows and columns)
I'm trying to solve the following linear (6x6) system that contains a row of zeros in it using LU decomposition and LU back substitution. coefficient matrix = 0.07192 -0.05664 -0.22443 -159.36051 0.00000 -0.01644 0.00000 -0.00000 -0.00000 -0.00000 0.00000 -0.00000 -0.14818... -
Using LAPACK library in fortran codes
Has anyone ever used LAPACK in their fortran(90) codes? I believe this can help me compare the results from my hand-coded linear-algebra codes - or even replace these in case LAPACK gives far better performance. Small pieces of example code might be helpful. I've also tried installing this... -
Appropriate use of allocatable arrays
When I compile and link the following piece of code in the relevant program (main), all works perfectly and the executable is formed successfully. But when running the executable I find that the matrix "A" in "Ax=b" is singular (only zeros, in fact). I suspect this is due to the way I have used... -
3D array data storage
Hi. I'm working with 1D and 2D f90 arrays. Actually, for a fixed value of a looping/iteration index, I have to form a 2D (dimension(6,6) ) array that holds some Jacobian matrix. Calling this iteration counter i, where i ranges from 0 to n (say n=5000), this means I need to compute the 6x6... -
Finite difference approximation of Jacobian
Hi. I'm implementing a forward finite difference approximation of the Jacobian matrix (2x2). I have adapted a subroutine (fdjac) from somewhere.The issue is that this subroutine requires explicit interfaces because of the deferred shapes of the involved arrays. 1. May I please have tips on... -
Linking Fortran 90 code with 'gfortran' compiler on linux ubuntu 11.10
Hi. Please pardon me if this is not a very relevant topic here. I just thought someone might help out. I have a slight problem linking my f90 code now on my linux ubuntu 11.10 system. Compiling procedes well. However, when linking, an error message is generated. This started after I installed... -
implementing Newton-Raphson mehtod in f90
I am adapting a version of the Newton-Raphson code found in Numerical Recipes in Fortran90 (page 275/572) for solving f(x) = 0. The code (a fortran function) together with a subroutine plus a driver (main) program I have made appear to work with some function f(x). But a different f(x) gives...
