2 isident - returns 1 if matrix is an identity matrix
13 This function returns 1 if m is an 2 dimensional identity matrix,
17 > mat x[3,3] = {1,0,0,0,1,0,0,0,1};
28 mat, matdim, matfill, matmax, matmin, matsum, mattrans,
29 isassoc, isatty, isblk, isconfig, isdefined, iserror, iseven, isfile,
30 ishash, isint, islist, ismat, ismult, isnull, isnum, isobj,
31 isobjtype, isodd, isprime, isrand, israndom, isreal, isrel,
32 issimple, issq, isstr, istype