Animating two functions

[tmiethlinger]

Hello,

I wanted to ask if it's possible to animate two functions? I tried to expand the "demo_animation" in example-misc.cc, but that didn't work.

I tried the following code, among others:

#include
#include
#include
#include
#include
#include

#include "gnuplot-iostream.h"

#define M_PI 3.14159265358979323846

#include <unistd.h>
inline void mysleep(unsigned millis)
{
::usleep(millis * 1000);
}

void animation()
{
Gnuplot gp;

std::cout << "Press Ctrl-C to quit (closing gnuplot window doesn't quit)." << std::endl;

gp << "set yrange [-1:1]\n";

const int N = 1000;
std::vector<double> f1(N);
std::vector<double> f2(N);

double theta = 0;
while(true)
{
    for(int i=0; i<N; i++)
    {
        double alpha = (static_cast<double>(i)/N - 0.5) * 10;
        f1[i] = sin(alpha*8.0 + theta) * exp(-alpha*alpha/2.0);
        f2[i] = sin(alpha*8.0 + theta) * exp(-alpha*alpha/1.0);
    }

    // 1 function: works
    gp << "plot" << " '-' binary" << gp.binFmt1d(f1, "array") << "with lines title 'f1(x)'\n";
    gp.sendBinary1d(f1);
    gp.flush();

    // 2 functions: doesn't work
    //gp << "plot" << " '-' binary" << gp.binFmt1d(f1, "array") << "with lines notitle";
    //gp.sendBinary1d(f1);
    //gp << "plot" << " '-' binary" << gp.binFmt1d(f2, "array") << "with lines notitle\n";
    //gp.sendBinary1d(f2);
    //gp.flush();

    mysleep(10);
    theta += 0.05;
}

}

int main(int argc, char *argv[])
{
animation();
}

How can I include more than one function in the animation? And is it necessary to use binary here, or could I also use other functions like add_plot1d?

Thank you for your help,
Thomas

[dstahlke]

Try it like this:

gp << "plot" << " '-' binary" << gp.binFmt1d(f1, "array") << "with lines notitle";
gp << ", '-' binary" << gp.binFmt1d(f2, "array") << "with lines notitle\n";
gp.sendBinary1d(f1);
gp.sendBinary1d(f2);
gp.flush();

And yes, you can use add_plot1d. Though it's not an animation, example-data-1d.cc gives an example of plotting many functions at once. To animate, you'd just have to call it in a loop.