# Documentation of pnsemilogy

Global Index (all files) (short | long) | Local Index (files in subdir) (short | long)

## Function Synopsis

`[h, c] = pncont(xa, ya, x, clev, lab, s);`

## Help text

```     [h, c] = pncont(xa, ya, x, clev, lab, s);

This function will plot positive contours of x in solid
lines, and negative contours of x in dashed lines.

pncont(x) pncont's the matrix 'x'.
pncont(xa, ya, x) uses xa and ya as the x and y axes resp.
pncont(xa, ya, x, clev) uses levels outlined in 'clev', or if
clev is an integer, uses clev levels.
pncont(xa, ya, x, clev, lab) lab = 0 => don't label contours (default)
lab = 1 => label contours

pncont(xa, ya, x, clev, lab, s) s is a string containing the
various plotting conventions.
e.g. s = ['--k'] or whatever.

```

## Cross-Reference Information

This function calls

## Listing of function pnsemilogy

```function [h, c] = pncont(xa, ya, x, clev, lab, s);

%cla
nexta = lower(get(gca, 'NextPlot'));
nextf = lower(get(gcf, 'NextPlot'));

if ~hold_state; cla; end;

lw = 1;

if nargin == 1;
x = xa;
[m, n] = size(x);
xa = 1:n;
ya = 1:m;
end;
if nargin < 4; clev = 10; end;
if nargin < 5; lab = 0; end;
if nargin < 6;
if nargin == 5
if isstr(lab);
s = lab; lab = 0;
else
lab = s; s = [];
end
else
s = [];
end
end

if isscalar(clev);
minx = min(min(x));
maxx = max(max(x));
cint = (maxx - minx + 2*eps) / clev;
clev = (minx+eps):cint:(maxx+eps);
end

[m,n] = size(x);

xp = eps * ones(m,n);
xn = -1 * eps * ones(m,n);
for i = 1:m;
for j = 1:n;
if x(i,j) <= 0;
xp(i,j) = 0;
xn(i,j) = x(i,j);
else;
xp(i,j) = x(i,j);
xn(i,j) = 0;
end;
end;
end;
hold on
h = []; c = [];
if (max(max(x)) > clev(find(clev == min(clev(find(clev > 0))))))
[a, b] = semilogy(xa, ya, xp, clev(find(clev)), ['-' s]);
if lab; clabel(a, b, 'manual'); end;
set(b,'linewidth',lw);
h = [b];
c = [a];
end;
if (min(min(x)) < clev(find(clev == max(clev(find(clev < 0))))));
[cc, d] = semilogy(xa, ya, xn, clev(find(clev)), ['--' s]);
if lab; clabel(c, d, 'manual'); end;
set(d,'linewidth',lw);
h = [h; d];
c = [c cc];
end;
if (max(max(x)) > 0) & (min(min(x)) < 0 & ismember(0,clev) )
[e, f] = semilogy(xa, ya, x, [0 0], ['-' s]);
if lab; clabel(e, f, 'manual'); end;
set(f,'linewidth',2*lw);
h = [h; f];
c = [c e];
end;
hold off
grid on;

```