test.txta=[1 2 3;4 5 6];fid=fopen('text.txt','w');count=fwrite(fid,a,'int32')closestatus=fclose(fid)fid=fopen('test.txt','r');a=fread(fid,[2 3],'int32');closestatus=fclose(fid);b=magic(3)c=a*b这里的[2 3]是什么意思?