Solved by ptrblck in post #4 
              
              
                This should be the case when using scatter_, and I guess I had some intermediate results stored in Fint_MAT. 
After rerunning I get these results: 
tensor([[-0.8591,  0.8688,  1.2835,  0.9208,  0.1976,  1.0741, -1.4244,  0.9609,
          1.0544,  0.2955, -2.0284,  2.2574,  0.2363, -0.5887,  0.4460,…