/* Identity matrix, in Jsish */
function identityMatrix(n) {
    var mat = new Array(n).fill(0);
    for (var r in mat) {
        mat[r] = new Array(n).fill(0);
        mat[r][r] = 1;
    }
    return mat;
}

provide('identityMatrix', 1);

if (Interp.conf('unitTest')) {
;    identityMatrix(0);
;    identityMatrix(1);
;    identityMatrix(2);
;    identityMatrix(3);
    var mat = identityMatrix(4);
    for (var r in mat) puts(mat[r]);
}

/*
=!EXPECTSTART!=
identityMatrix(0) ==> []
identityMatrix(1) ==> [ [ 1 ] ]
identityMatrix(2) ==> [ [ 1, 0 ], [ 0, 1 ] ]
identityMatrix(3) ==> [ [ 1, 0, 0 ], [ 0, 1, 0 ], [ 0, 0, 1 ] ]
[ 1, 0, 0, 0 ]
[ 0, 1, 0, 0 ]
[ 0, 0, 1, 0 ]
[ 0, 0, 0, 1 ]
=!EXPECTEND!=
*/