Sure. Thanks! ... View more

I like it! Thanks! ... View more

Thanks! I like it! ... View more

Thanks very much WarrenKuhfeld, but I could't see your code clearly. Could you please make up a matrix (say a={1 2 3 5}) and retype the code? ... View more

Great! This works! ... View more

Thanks for your reply. Any more specific suggestions? ... View more

Thanks very much for your reply, Ksharp. The result we want should have 6 elements {1,2,3,5,6,10,15}, but yours returns more than that. I think the problem is that when you define bad_idx, you only include the indexes of the diagonal elements.  Could you please revise your code? ... View more

Hi Rick, thanks for your help. I figured out how to use HDIR when matrices have missing value.  However, a new issue comes out. Since we have 17 interested variables, we will get 17*17=289 terms when we use HDIR, but what we want is just 17*16/2=136 two-way interaction terms. The result by using HDIR has repeated interaction terms besides quadratic terms. Say if we have 3 variables a,b,and c, HDIR will give us aa,ab,ac,ba,bb,bc,ca,cb,and cc.  Do you have any suggestions on this? ... View more

Thanks very much. I like your ideas. ... View more

Thanks very much. You answer really helps. ... View more

I read "Matrix multiplication with missing values in SAS" before. However, it does not answer my questions on HDIR. ... View more

Thanks very much for your reply. I am doing my research on interaction effects. We have a large dataset with 17 interested predictors. All the predictor variables have missing values. I need to create a new data set with all the 2-way interaction effects. I think horizontal direct product (HDIR) in SAS can help me create those interaction effects. First, I have successfully read all the predictor variables into a matrix (denoted by matrix_L18_Q34) in SAS.  Then I try to do use the code "interaction_matrix_L18_Q34 = hdir(matrix_L18_Q34, matrix_L18_Q34)". However, it shows that "ERROR: (execution) Matrix has not been set to a value."   Here is the log:   1 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK; 59 60 /* read all interested predictor variables (a to q) into matrix matrix_L18_Q34 */ 61 proc iml; NOTE: IML Ready 62 use L18_Q34; 63 read all var ("a":"q") into matrix_L18_Q34[colname=varNames]; 64 print varNames; 65 print matrix_L18_Q34; 66 67 68 /*Horizontal Direct Product*/ NOTE: Exiting IML. NOTE: PROCEDURE IML used (Total process time): real time 2.64 seconds user cpu time 2.61 seconds system cpu time 0.00 seconds memory 4135.40k OS Memory 32168.00k Timestamp 07/02/2017 07:29:14 PM Step Count 24 Switch Count 50 Page Faults 0 Page Reclaims 847 Page Swaps 0 Voluntary Context Switches 157 Involuntary Context Switches 272 Block Input Operations 0 Block Output Operations 1440   69 proc iml;   NOTE: IML Ready 70 interaction_matrix_L18_Q34 = hdir(matrix_L18_Q34, matrix_L18_Q34); ERROR: (execution) Matrix has not been set to a value.   operation : HDIR at line 70 column 34 operands : matrix_L18_Q34, matrix_L18_Q34   matrix_L18_Q34 0 row 0 col (type ?, size 0)     matrix_L18_Q34 0 row 0 col (type ?, size 0)     statement : ASSIGN at line 70 column 1 71 print interaction_matrix_L18_Q34; ERROR: Matrix interaction_matrix_L18_Q34 has not been set to a value.   statement : PRINT at line 71 column 1 72 73 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK; 85 ... View more