NAME
    isident - returns 1 if matrix is an identity matrix

SYNOPSIS
    isident(m)

TYPES
    m		any

    return	int

DESCRIPTION
    This function returns 1 if m is an 2 dimensional identity matrix,
    0 otherwise.

EXAMPLE
    > mat x[3,3] = {1,0,0,0,1,0,0,0,1};
    > isident(x)
	    1

LIMITS
    none

LIBRARY
    none

SEE ALSO
    mat, matdim, matfill, matmax, matmin, matsum, mattrans,
    isassoc, isatty, isblk, isconfig, isdefined, iserror, iseven, isfile,
    ishash, isint, islist, ismat, ismult, isnull, isnum, isobj,
    isobjtype, isodd, isprime, isrand, israndom, isreal, isrel,
    issimple, issq, isstr, istype