Re: How do I make a log-log plot?



>>>>> "Robert" == Robert Dodier  writes:

    Robert> Well, how about this. 

    Robert> (1) logx and logy are boolean plot_options which indicate
    Robert> logarithmic transform of the x and y axes respectively.

This is ok with me.

    Robert> (2) redefine function to plot as f(exp(x)), log(f(x)), or log(f(exp(x)))
    Robert> (hope I got that right)

    Robert> (3a) if plot type supports logarithmic transform:
    Robert> (at present I believe this is only gnuplot and mgnuplot)
    Robert> emit plot package option to turn on log transform

    Robert> (3b) otherwise: somehow indicate the axes have been transformed
    Robert> maybe change axis label? seems problematic.
    Robert> maybe print a message on the console? not sure.


Well, with gnuplot, you really want f(x) sent to gnuplot because it
computes the log of the x and/or y axes itself.  What maxima needs to
do is make sure we sample f(x) logarithmically on the x axis so the
plot is smooth.

I could make the appropriate changes for gnuplot so that logx and/or
logy sends the appropriate command to gnuplot for log plots.  I'm not
very familiar with the rest so it will take some time to support
them.  

I also will ignore the issue of the user saying logx but having a
gnuplot plot option saying not to do log x plots.

Ray