Cfrtjryk

I use this function:

documentclass{standalone}

usepackage{tikz}

usepackage{pgfplots}

pgfplotsset{compat=1.15}



    begin{document}

        newcommand{xmax}{14}

        newcommand{fmin}{(pi/3)}

        newcommand{fmax}{(2*pi)}

    begin{tikzpicture}

    [domain=xmax:0, samples=500]





    % The following line uses linear frequency increase

    %draw[ultra thick, red] plot (x, {sin(deg((fmin+x*((fmax-fmin))/xmax)*x))} );

    % The following line uses exponential frequency increase

    draw[ultra thick, red] plot (x, {sin(deg(exp(ln(fmin)+x/xmax*(ln(fmax)-ln(fmin)))*x))} );

    end{tikzpicture}

    end{document}

I need to evaluate the x parameter.
How can I print it's value?
also on log file is ok

Renato

To print all the points that the draw...plot is using, you can:

documentclass{article}

usepackage{tikz}

usepackage{pgfplots}

pgfplotsset{compat=1.15}



begin{document}

newcommand{xmax}{14}

newcommand{fmin}{(pi/3)}

newcommand{fmax}{(2*pi)}

begin{tikzpicture}

    [domain=xmax:0, samples=500]

    draw[ultra thick, red] plot (x, {sin(deg(exp(ln(fmin)+x/xmax*(ln(fmax)-ln(fmin)))*x))} );

end{tikzpicture}



pgfmathsetmacro{step}{xmax/500}

foreach x in {0,step,...,xmax} {

    x, qquad 

    pgfmathparse{sin(deg(exp(ln(fmin)+x/xmax*(ln(fmax)-ln(fmin)))*x))}pgfmathresult

    par

}



end{document}

(continuing...)

If you want the output on the log file, you can add (after the par, for example)

 wlog{x is xspace and the function pgfmathresult} 

and you'll have in your .log file:

x is 0 and the function 0.0

x is 0.028 and the function 0.02939

x is 0.056 and the function 0.05899

x is 0.084 and the function 0.08878

x is 0.112 and the function 0.11867

For the strange space, see Space after command with write

Clearly, to have it only on the log file, use as the loop:

foreach x in {0,step,...,xmax} { 

        pgfmathparse{sin(deg(exp(ln(fmin)+x/xmax*(ln(fmax)-ln(fmin)))*x))}

        wlog{x is xspace and the function pgfmathresult} 

    }

You don't give us much information in your question, so I'm just using some dummy numbers....

documentclass{article}



usepackage{tikz}





begin{document}



defx{0.5}

defxmax{1}

deffmin{1}

deffmax{5}





pgfmathparse{sin(deg(exp(ln(fmin)+x/xmax*(ln(fmax)-ln(fmin)))*x))}pgfmathresult





end{document}