[R] matrix balancing on margins

[PALMIER Patrick - CETE NP/INFRA/TRF]

Hello,

Is there any package in R for balancing matrix

I want to estimate a matrix with

    *  a initial matrix (1 everywhere for example)
    * Row margin
    * Col margin
    * distance class  vector  (each cell of the matrix  belong to a
      distance class) and I want that the distance class repartition
      will be preserved

How can I do such thing?
Is there any function already existing or should I compute an iterative 
script myself?

Thanks
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