In Matlab, how can I draw the bar graph in a semi-log scale? I know
this can be done easily from a plot command, but what I want is to
have a bar graph in semi-log scale.

Hello Matlabuser,

The page at
  http://mathforum.org/epigone/comp.soft-sys.matlab/flelblerdvim
or more directly at
http://mathforum.org/epigone/comp.soft-sys.matlab/flelblerdvim/eef3ea3.1@webx.raydaftYaTP
describes a method that generates a chart that basically does what you
are asking for. The steps can be summarized as follows:

1. Plot a "simple" set of data as semilogx or [more likely] semilogy.

2. Hide the simple data plot (retaining the axes).

3. Plot the bars for that data, axes, and so on.

Note for step 3 that you need to avoid using zero as a value for the
log scale and pick a reasonable "upper limit" as well. The page I
refer to goes into more detail for a pair of data points.

Another alternative is to convert your Y values to log(Y). Then
generate your bar chart and provide the original Y values in another
way (e.g., label each bar with the original Y value or an accompanying
table).

Neither method is particularly elegant but both are feasible in
Matlab. Another alternative is to export the data and generate a
semilog chart using another tool such as Microsoft Excel, GNUplot
(free), or several other programs.

Search phrases included:
  matlab bar chart scale
  matlab bar chart semilog

  --Maniac