I have a question on the use of %macro. I am using the code of a published paper to build my own indicator  and I faced many  problems.    Code :      %macro decomp(ctr,num); proc iml; use vbs; read all var _all_ into vbs; use texpfd(drop = ctr sec domdmd texpfd) ; read all var _all_ into expf; /*make DVAsh to zero */ k = 0; do i = 1 to 1435 by 35;   j = i+34;   k = k + 1; rows = i:j; cols = k:k; vbs[rows,cols] = 0; end; indvaexp=vbs[,&num]#expf; quit; %mend decomp   my problem is  %macro (ctr ,num)  . Is num refering to the fact that it is a numeric variable ?  and the last code indvaexp=vbs[,&num]#expf. What is the meaning of vbs[,&num] . I know that we use & to make reference to a macro variable but I tried to compute without macro ( indvaexp=vbs#expf) but I don't get the same result .    Can you help me please ? ... View more