GSLIB Help Page: LUSIM
Description:
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Creates Gaussian-based realizations with LU matrix method
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Parameters:
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datafl: the input data are in a simplified Geo-EAS formatted
file.
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icolx, icoly, icolz, and icolvr: the column numbers for
the x,y and z coordinates, and the variable to be
simulated. One or two of the coordinate column numbers can be set
to zero which indicates that the simulation is 2-D or 1-D.
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tmin and tmax: all values strictly less than tmin
and strictly greater than tmax are ignored.
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idbg: an integer debugging level between 0 and 3. The higher
the debugging level the more output.
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dbgfl: a file for the debugging output.
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outfl: the output grid is written to this file. The output
file will contain the grid, cycling fastest on x then y
then z and last per simulation.
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nsim: the number of simulations to generate.
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nx, xmn, xsiz: definition of the grid system (x axis).
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ny, ymn, ysiz: definition of the grid system (y axis).
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nz, zmn, zsiz: definition of the grid system (z axis).
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seed: random number seed (a large odd integer).
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nst and c0: the number of variogram structures and the
isotropic nugget constant.
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For each of the nst nested structures one must define it
the type of structure; cc the c parameter;
ang1,ang2,ang3 the angles defining the geometric anisotropy;
aa_hmax, the maximum horizontal range; aa_hmin,
the minimum horizontal range; and aa_vert, the vertical range.
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Application notes:
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This program requires standard normal data and writes standard normal
simulated values. Normal score transform and back transform are to be
performed outside of this program
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Recall that the power model is not a legitimate model
for a multiGaussian phenomenon and it is not allowed in lusim
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The semivariogram model is that of the normal scores.
The kriging variance is directly interpreted as the variance of the
conditional distribution; consequently, the nugget constant c0
and c (sill) parameters should add to 1.0.