MATLAB: How to set XTickLabel with equal width between the ticks?for 1,2, 127, and 128

Question

width between 1 and 2 is small, similarly for 127 and 128. I need equal width for 1,2,127 and 128

Answer 1

Your graph is reproduced (with random y-values) by

x = [1 2 8:8:120 127 128];
y = rand(size(x));
figure, plot(x,y)
set(gca,'xtick',x)

Alternatively, you can plot y against the index of x:

xi = 1:19;
figure, plot(xi,y)

Now we can put the xticks at the index, but use x for the ticklabels:

set(gca,'xtick',xi,'xticklabel',x)

Not sure if this result is what you meant (or why it would be useful). Let me know if it helps.