Hi, 
    I am trying to figure out how to evaluate the density function of 
multivariate normal efficiently for a large data set, the 
data set should look like this (take d=2 for example): 
          
           data                                        mean                     
                 sigma

       2.131, 3.000                       1.000,1.000                           
          1   0
                                                                                
                                0   1

       1.231,5.141                        2.000,2.000                           
           .5  -.1
            .............                                 .............         
                                 -.1 .4
                                                                                
                                 .........

that is , I need   SUM_i (log(dmvnorm(d[i], mu[i], sigma[i])).     tried to 
rewrite the dmvnorm function from mvtnorm 
package, but could not find a satisfactory method to avoid using loops.  ( 
using those "apply" functions seem to be slower
than loops) .  May I get some suggestion on this ? Thanks a lot in advance. 

best

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