topic Re: Multiply and substract matrices as datasets in SAS/IML Software and Matrix Computations

Multiply and substract matrices as datasets

Minh2710 — Sun, 28 Feb 2021 00:30:09 GMT

Hello everyone. I wonder how I can multiply and substract matrices if they are presented as datasets in SAS. It would be great if anyone can show me an example of how I can do it with the two datasets below:

data matrix_1;
	input a b c;
	cards;
	2 6 7
	1 8 3
	6 3 8
	;

data matrix_2;
	input a b c;
	cards;
	8 3 6
	1 7 9
	3 6 2
	;
run;

proc print data = matrix_1 noobs; run;
proc print data = matrix_2 noobs; run;

Re: Multiply and substract matrices as datasets

joseenrique1 — Sun, 28 Feb 2021 03:22:55 GMT

Hi,

Surely, there is a way to do it with data steps, but you can also do it with the IML procedure.

data matrix_1;
	input a b c;
	cards;
	2 6 7
	1 8 3
	6 3 8
	;

data matrix_2;
	input a b c;
	cards;
	8 3 6
	1 7 9
	3 6 2
	;
run;

proc iml;
	edit work.matrix_1;
	read all var _NUM_ into matrix_1[colname=numVars];;
	close work.matrix_1;	
	
	print matrix_1;

	edit work.matrix_2;
	read all var _NUM_ into matrix_2[colname=numVars];;
	close work.matrix_2;	
	
	print matrix_2;
	
	mult = matrix_1*matrix_2;
	
	print mult;
	
	subs = matrix_1 - matrix_2;
	
	print subs;

run;

results

Hope that this can help you

Enrique

Re: Multiply and substract matrices as datasets

PeterClemmensen — Sun, 28 Feb 2021 06:52:52 GMT

Moved the thread to the IML Forum.

Re: Multiply and substract matrices as datasets

Rick_SAS — Sun, 28 Feb 2021 12:03:42 GMT

Enrique gave the correct answer, although I recommend that you use the USE statement to read the matrices:

	use matrix_1;
	read all var _NUM_ into matrix_1;
	close;

If needed, you can also read individual variables into SAS/IML vectors.

Re: Multiply and substract matrices as datasets

Minh2710 — Sun, 28 Feb 2021 16:33:20 GMT

Thank you very much. It worked like a charm.