Warning: Negative data ignored

I want to know how to plot negative value. I have imported data from excel file to plot in matlab. In data i have negative value but i can't able to see graph at negative value.

Plz help to find solution. And how to do to see negative curve.

 plot(freq,x);hold all;plot(freq,y);hold off;figure(gcf);
Warning: Negative data ignored 
Warning: Negative data ignored

Answer 1

[Tom Lane]

Could you have already had "hold on" in effect for a plot with log axes? The following commands illustrate what I mean:

semilogy(rand(10,1),rand(10,1),'bo') % you could get the error by doing this,
hold on                              % then turning hold on,
plot(rand(10,1),randn(10,1),'rx')    % <- if your code fragment started here

Answer 2

[Image Analyst]

Try using "hold on" instead of "hold all".

[Jan]

Why? "hold all" cares about the color order also, as far as I remember.

[Image Analyst]

I thought that maybe hold all would lock down the Y axis limits and then if you tried to plot y outside of those limits, then it might not be able to plot some. It was just a guess.

Answer 3

[Jan]

The shown code works with negative values also:

freq = 1:10;
x = linspace(-5, 5, 10);
y = linspace(5, -5, 10);

plot(freq,x);
hold('all');
plot(freq,y);
hold('off');
figure(gcf);

Therefore something else must be going wrong. Perhaps you have set any properties or other GUI obejcts to invalid values before, e.g. the 'Value' of an uicontrol to -1. Please post the relevant part of the code then.