I cannot use the vmatch provided by you because it has the proc optnet and I'm still on 9.3 M1.
I've used the proc optmodel but it runs out of memory:
proc optmodel;
/* define sets for cases and controls */
set <str> CASES;
set <str> CONTROLS init (union{i in 1..12574} {"control"||i});
/* define cost parameter */
num cost{CASES, CONTROLS};
/* read in data including missing values */
read data tr into CASES = [key] {j in CONTROLS} < cost[key, j] = col(j) >;
/* create a set of pairs which are possible, i.e. cost is not missing */
set <string, string> POSSIBLE = {i in CASES, j in CONTROLS: cost[i,j] >= 0};
/* we only need variables for possible pairs */
var Assign{CASES,CONTROLS} >= 0;
num maxCost = max{<i,j> in POSSIBLE} cost[i,j];
min z = sum {<i,j> in POSSIBLE} cost[i,j]*Assign[i,j] /*- sum {<i,j> in POSSIBLE} (maxCost+1)*Assign[i,j]*/;
*** Constraint that each case has to be assigned to one control ***;
con case_assign{i in CASES}: sum{<(i),j> in POSSIBLE}Assign[i,j] <= 4;
*** Constraint that each control can be used only once ***;
con control_assign{j in CONTROLS}: sum{<i,(j)> in POSSIBLE} Assign[i,j] <= 1;
/* solve the model */
solve with lp;
/* print the result */
*print Assign;
create data assign from [i j] = {i in CASES, j in CONTROLS: Assign[i,j] >= 0.5} cost;
quit;
I've tried the vmatch downloaded from Mayo but it runs 24 hours and I stopped:
%vmatch(dist = tr, idca = key, a = 1, b = 4, lilm = 12574, n = 3069, firstco = control3453, lastco = control1999
,print = n, out = result);
Finally I'm trying a simple proc assign, that with some modifications (deleting the controls picked,...) I'll repeat 4 times in order to get 4 controls but I got the error posted above:
proc assign data = tr out = result_1;
cost &start -- &end;
id key;
run;
