Marc Suñé Simon - 2013-10-29

How to generate a one-dimensional random noise with any correlation function g(z)?

The basic usage of Correlated random noise generator to generate a one-dimensional random isotropic correlated noise in a domain of N points and total length N delta is employed in corr.cpp and overviewed in what follows:

* Header *disorder.h* should be included at the preamble,    #include <disorder.h\>.
* The parameters to be defined are *N* (of type int, number of discretization points of the region in which noise will be defined), *delta* (of type double, discretization length) and *seed* (of type int, seed for the random number generator).
* The variables are *g(z)* (array of *N* doubles that stores the values of the correlation function at the discretization points) and *V(z)* (array of *N* doubles that stores the noise values at the discretization points).
* The correlation function *g(z)* should be defined and evaluated at the *N/2+1* points of the space, *g(z)=g(i·delta)*, *i=0,N/2*.
* The function *disorder_1d()* should be called. Its arguments are *N*, *delta*, *seed*, *g(i·delta)* and *V(i·delta)*. The former is where the random noise is saved.
* The code must be linked with the ***Correlated random noise generator*** library as well as with the *fftw3* and *CBLAS*. On Unix systems, link with *-lgsl -lgslcblas -lfftw3 -lm*.

How to generate a two-dimensional random noise with any correlation function g(z)?

Generation of a two-dimensional random isotropic correlated noise in a domain of N·N points and (N·delta)^2 surface is analogous to the unidimensional case. Again, corr.cpp includes an example of how to generate such noise applying the library Correlated random noise generator.

* Header *disorder.h* should be included at the preamble,    #include <disorder.h\>.
* The parameters to be defined are *N* (of type int, number of discretization points along each of the two perpendicular directions of the space in which noise will be defined), *delta* (of type double, discretization length along both directions) and *seed* (of type int, seed for the random number generator).
* The variables are *g(**z**)* (array of *N·(N+2)* doubles that stores the values of the correlation function at the discretization points) and *V(**z**)* (array of *N·(N+2)* doubles that stores the noise values at the discretization points).
* The correlation function *g(**z**)* should be defined and evaluated at the *(N/2+1)^2* points of the space, *g(**z**)=g(i·delta,j·delta)*, *i=0,N/2*, *j=0,N/2*.
* The function *disorder_2d()* should be called. Its arguments are *N*, *delta*, *seed*, *g(i·delta, j·delta)* and *V(i·delta, j·delta)*. The former is where the random noise is saved.
* The code must be linked with the ***Correlated random noise generator*** library as well as with the *fftw3* and *CBLAS*. On Unix systems, link with *-lgsl -lgslcblas -lfftw3 -lm*.
 

Last edit: Marc Suñé Simon 2013-10-29