ismatrix

ismatrix(ones(10,5))
ismatrix(1)
ismatrix(["s" "t" "u"; "t" "s" "u"])
ismatrix(rand(2,1,3)) //because of singleton
ismatrix(rand(2,2,3)) //hypermatrix
s = struct();
ismatrix(s) // Empty structure
clear s
s(1,2).a = 3;
s(1,3).b = %z;
ismatrix(s) // Row array of structures
clear s
s(2,1).a = "w"; 
s(3,1).b = %t;  
iscolumn(s) // Column array of structures
clear s
s(1,2).a = -2;
s(3,1).b = %pi;
ismatrix(s) // 2D not-square array of structures
clear s
s(2,1,2).a = 3;
s(1,1,2).b = "test";
ismatrix(s) // 3D array of structures (with a singleton dim)
clear s
s(1,1,2).a = 3;
s(1,1,3).b = "test";
ismatrix(s) // 3D array of structures (with 2 singleton dims)
clear s
s(2,2,2).a = %f; 
s(1,2,1).b = list(%e, %s);
ismatrix(s) // 3D (cubic) array of structures