LOGLOGPN

LOGLOGPN(...) is the same as LOGLOG(...), except that the Y data may have positive and negative values. This is useful to detect unexpected negative values in the Y data (causing repeated 'Negative data ignored' warnings), or to visualize the magnitude of an oscillating signal in log scale.

LOGLOGPN(X,Y) plots X versus Y in log-log scale, where Y may have positive and negative values. By default, negative values are plotted with dashed lines and positive values with full lines. If X is not specified, Y is plotted versus its index.

LOGLOGPN(X,Y,LineSpecPos,LineSpecNeg) specifies LineSpecPos and LineSpecNeg for the line types, marker symbols and colors for the positive and negative values of Y. For instance, LOGLOGPN(X,Y,'ro-','b*') plots the positive Y with red line and 'o' markers and the negative Y with blue stars '*'.

LOGLOGPN(X,Y,LineSpecPos,LineSpecNeg,'PropertyName',PropertyValue,...) sets property values for all lineseries graphics objects created by LOGLOGPN. See the line reference page for more information.

[HP, HN] = LOGLOGPN(...) returns the handles to the two lineseries graphics objects.

Similarly, SEMILOGYPN(...) works like SEMILOGY(...).

Examples:
x = linspace(1,10,200);
y = sin(x*2)./x;
loglogpn(x,y,'r.','bo');
axis([1 10 1e-2 1]);

loglogpn(x,y,'b-','r:','LineWidth',2);

[hp, hn] = loglogpn(x,y,'k');
set(hp, 'LineWidth', 1);
set(hp, 'LineWidth', 2);