Dear friends,

I am doing cokriging and i could not fit the LMC to my variograms
automatically, therefore i ftted the LMC manually. i have a total of 15
variograms (direct variograms and cross variograms). eg:

clay.g$model$clay[1,2]
clay.g$model$clay[1,2] = 0.22
clay.g$model$clay[2,2] = 0.15
clay.g$model$evi[1,2] = 0.005
clay.g$model$evi[2,2] = 0.0105
clay.g$model$clay.evi[1,2] = 0.185
clay.g$model$clay.evi[2,2] = 0.025

then i checked my matrices with this condition which they need to
satisfy:nugget(clay.evi)
=<sqrt(nugget(clay) * nugget(evi)) and i got something like this for
example:
clay.g$model$clay[1,2] = 0.22
clay.g$model$clay[2,2] = 0.15
clay.g$model$evi[1,2] = 0.005
clay.g$model$evi[2,2] = 0.0105
clay.g$model$clay.evi[1,2] = 0.030
clay.g$model$clay.evi[2,2] = 0.025


still after this correction i am getting this error:
 predict.gstat(clay.g, newdata = dem)
non-positive definite coefficient matrix in structure 1non-positive definite
coefficient matrix in structure 2Warning: No Intrinsic Correlation or Linear
Model of Coregionalization found
Reason: coefficient matrix not positive definite
Warning: [add `set nocheck = 1;' to the command file to ignore the following
error]
Error in predict.gstat(clay.g, newdata = dem) :
  gstat: value not allowed for: variograms do not satisfy a legal model
May you please help, what went wrong and how to solve this.
Thanks for your usual co-operation,

Nikkie

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