semilogx
Semi-log plots, with logarithmic scaling along the x-axis.
semilogx(x)
semilogx(x,plotspec)
semilogx(x,y)
semilogx(x,y, plotspec)
semilogx(x1,y1, plotspec1, x2, y2, plotspec2,...)
 Inputs x A matrix. y A matrix. {x1, y1, x2, y2,..} Matrices. plotspec Plot style specification string. {plotspec1, plotspec2,..} Plot style specification strings.

Description
semilogx(x) draws the semilog plot of the input, with logarithmic (to the base 10) scaling of the coordinates along the x-axis. If the input is a vector, its elements are plotted against the vector [1:n] where n is the size of the input. If x is a matrix, the vectors x[:,i], i>1 are plotted against the first column x[:,1] of the input.

semilogx(x, y) displays a semilog plot of the columns in y vs. the columns in x . The numbers of rows is in y must be identical to the number of rows in x or, if x is a vector, to the number of elements in it.

If the first input is a vector, the semilog plots of every column in y vs. x are displayed.

If the two inputs have identical number of columns, the function displays the area plot of every column in y vs. the corresponding column in x .

If the number of columns, n , in x is not identical to p , the number of columns in y , the area plots of y[:,i] vs. x[:,mod(i,n)+1] for 1<=i<=p are displayed.

The parameter plotspec may be used to control the style and the color of each plot as defined in plot.

The call semilogx(x1,y1, plotspec1, x2, y2, plotspec2,...) is similar to semilogx(x, y, plotspec) in that the function displays a semilogx plot for each of the triples {x1, y1, plotspec1} , {x2, y2, plotspec2} in the same manner as the call with three arguments.
Example
>>y=rand(100,1)
>>semilogx([1:100],y,'r')
>>title("Semi-Log-X Plot")
>>xlabel("X-Axis")
>>ylabel("Y-Axis")