How can I convert a variable whose value is double to integer or to float?

How can I convert a variable whose value is double to integer or to float? So I think I can fix the problem:

Undefined function 'roundn' for input arguments of type 'double'.

Error in plot_litho_061015 (line 58) drawLine([0 roundn(z1),2], [0 min(z1)]); hold on; % Vertical line at x = 0;

ps: z1 value= 2601x1double

Answer 1

[bio lim]

z1 = rand(2601,1);
int_z1 = int8(z1);

I don't really understand what you mean by "float". Are you refering to single-precision? If so,

 single(z1)

In general, MATLAB functions usually require doubles.

[Marco Ottina]

yeah, "float" is the name of "single-precision" in C and C++

Answer 2

[SIFISO NICHOLUS]

double Z = 2.55555