converting an edgelist dataset to an adjacency matrix, setting missing values as 0

[Ksharp]

/*
You need process them bofore PROC IML.
*/
proc import datafile='c:\temp\book6.xlsx' out=Sheet1 dbms=xlsx replace;
sheet='Sheet1';
run;
proc import datafile='c:\temp\book6.xlsx' out=Sheet2 dbms=xlsx replace;
sheet='Sheet2';
run;

proc iml ;
use sheet1(where=(id is not missing)) ;
read all var _num_ into layer1 ;
close;
use sheet2(where=(id is not missing)) ;
read all var _num_ into layer2 ;
close;

 
/*There are only 9 columns(exclude ID),so should be 8:9*/
A = layer1[1:2,8:9] ;
B = layer2[1:2,8:9] ;
c = A # B ;
quit;

[Max123]

why aren't matrices A, B, C created in the work lib?

[Rick_SAS]

Because they are not data sets. They are matrices, which are created in RAM. They disappear after you QUIT the procedure.

If you need to write the final result to a data set, you can do that by using the CREATE/APPEND statements:
https://blogs.sas.com/content/iml/2011/04/18/writing-data-from-a-matrix-to-a-sas-data-set.html 

[Ksharp]

/*
Follow the Rick's blog,
You need more code to save these matrix .
*/

proc iml ;
use sheet1(where=(id is not missing)) ;
read all var _num_ into layer1 ;
close;
use sheet2(where=(id is not missing)) ;
read all var _num_ into layer2 ;
close;

A = layer1[1:2,8:9] ;
B = layer2[1:2,8:9] ;
c = A # B ;

create want var{A B C};
append;
close;
quit;

[Tom]

If the nodes are identified by a series of integers (and if not you could always just sort and number them) 

And the number of nodes is reasonable (and if not you are going to have a hard time doing calculations).

Then just make a 2-D array.  You can then write the 2-D array out as a dataset.

Example:

data have;
  input from to ;
cards;
1  2
1  3
4  5
5  2
6  7
8  7
;

data matrix ;
  array x[8,8] _temporary_ (64*0);
  do until (eof);
    set have end=eof;
    x[from,to]=1;
    x[to,from]=1;
  end;
  do node=1 to 8;
    array nodes [8] node1-node8 ;
    do col=1 to 8;
      nodes[col]=x[node,col];
    end;
    output;
  end;
  keep node: ;
run;

Result

Obs    node    node1    node2    node3    node4    node5    node6    node7    node8

 1       1       0        1        1        0        0        0        0        0
 2       2       1        0        0        0        1        0        0        0
 3       3       1        0        0        0        0        0        0        0
 4       4       0        0        0        0        1        0        0        0
 5       5       0        1        0        1        0        0        0        0
 6       6       0        0        0        0        0        0        1        0
 7       7       0        0        0        0        0        1        0        1
 8       8       0        0        0        0        0        0        1        0

If you want the main diagonal to be 1's then add this statement after the ARRAY statement in the DO NODE loop.

    nodes[node,node]=1;

[PGStats]

This page references 7 different measures of node centrality.

Which centrality measure do you want to calculate? And do you want to do the calculation with SAS or simply provide a well formatted file to other software?

[Max123]

Ultimately, I want the centrality (eigenvector, degree, betweenness, closeness) scores for each node, in SAS... I don't actually care for the intermediate steps. It was my assumption that I needed the adj. matrix before calculating the scores

[Tom]

---

@Max123 wrote:
Ultimately, I want the centrality (eigenvector, degree, betweenness, closeness) scores for each node, in SAS... I don't actually care for the intermediate steps. It was my assumption that I needed the adj. matrix before calculating the scores

---

And how to you propose to calculate those scores?  

Do you know the algorithm needed?

[Max123]

found this example online:
proc netflow in=network out=degree_centrality action=stats;
stats degree / type=degree;

[PGStats]

These network (graph) statistics are now available from PROC OPTGRAPH, for which you need the SAS Network Algorithms license.

From the procedure documentation, you only need a links (i.e. from-to pairs) dataset to get it going.

The centrality statistics are requested with the CENTRALITY statement.

[Max123]

unfortunately, I don't have that license. and PROC NETFLOW is not working...