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User forums => Using Code::Blocks => Topic started by: Glxblt76 on December 27, 2015, 11:29:40 am

Title: [SOLVED] koolplot: merging several functions expressions to one graph
Post by: Glxblt76 on December 27, 2015, 11:29:40 am

Dear Code::Blocks users and developers, :)

I'm looking for the right platform to ask my question but it turns to be quite difficult. It concerns the koolplot plugin implemented in Code::blocks EP, which enables to print graphs easily from C code. More information >> here  (http://koolplot.codecutter.org/) <<.

My question is simple. How to specify to koolplot functions a "spline" function, that is, a function which follows different expressions in different ranges? For example, from x=-6 to x=-4, I want a kind of minus inverse function, then from -4 to -3 I want a linear function, and from -3 to 0 I want a constant function (horizontal line). How to specify such thing to Plotdata or whatever so it displays only one function with these 3 behaviors?

I tried to put several functions and to use breakplot, but I couldn't specify the range in which each function is defined, so for example I had the minus inverse function, the linear function and the horizontal line superimposed from -6 to 0.

Any help would be greatly appreciated.  :)

Title: Re: koolplot in Code::blocks EP: merging several functions expressions to one graph
Post by: Glxblt76 on December 30, 2015, 08:54:37 am

Trying to look for the answer myself, I found the solution to this problem. The solution was to use only one function, and generate manually all points using a function that I defined myself, then to append all points to the koolplot function. The code looks like this:

My user defined function:

Code

double ts_f_ln_c(double x, double tension_surface_cmc, double cmc, double pc20)
{
    /*all variables declarations and constants calculations*/

    if(x < log(cmc/1000.0)/2.303)
    {
        if(x < -pc20)
        {
                 y = /*something of minus inverse type*/;
        }
        else
        {
                y = /*something of linear type */;
        }
    }
    else
    {
        y = /*something constant*/;
    }
    return y;
}

And the koolplot part in my main:

Code

    /**kooplot graph of function with three different expressions**/
    plotdata x, y;
    clear(x);
    clear(y);
    for(i = 0 ; i < 1000 ; i ++)
    {
        x_graphe[i] = 0.0;
        y_graphe[i] = 0.0;
        x_graphe[i] = log(cmc/1000.0)/2.303 - 4.5 + 6.0 / 1000.0 * i;
        y_graphe[i] = ts_f_ln_c(x_graphe[i], tension_surface_cmc, cmc, pc20);
    }
    insert(x, x_graphe, 1000);
    insert(y, y_graphe, 1000);
    axesBotLeft(x, y, log(cmc/1000.0)/2.303 - 4.5, 20);
    axesTopRight(x, y, log(cmc/1000.0)/2.303 + 1.5, 80);
    plot(x, y);

So I consider this topic as SOLVED  :)