Round to the nearest odd multiple of a number

Question

is there a MATLAB function that can round to the nearest odd multiple of a number? For instance, if x = 1.1 and the number is 0.5, then x should be rounded to 1.5

I could come up with a function to round to the nearest multiple but not the nearest odd multiple

x = round(x*(1/number))/(1/number);

Answer 1

You need to modify your approach as follows:

• Use twice the step, that is, 2*number;
• Shift the input by half of the new step;
• Undo the shifting in the output.

y = round((x/(2*number)-.5))*(2*number)+number;

Example:

number = 2.5;
x = [-10:.01:10];
y = round((x/(2*number)-.5))*(2*number)+number;
plot(x,y)
grid on, axis equal, axis([-15 15 -12.5 12.5])