T:=[
1.26953,
1.04297,
0.703125,
0.535156,
0.425781,
0.363281,
0.324219,
0.570312,
0.519531,
0.480469,
0.578125,
no_data, #0.6875,
0.683594,
0.664062,
0.625
];

Title:="MPI on 7 processors, integration with 2^22 trapezoids";
plotsetup(x11);

plot([p->T[1]/p,[[p,T[p]] $p=1..15]],1..15, 0..1.5, color=[blue,red], labels=[processes,"time in sec"], title=Title, legend=["perfect","actual"]);

plot({p->p,[[p,T[1]/T[p]] $p=1..15]},1..15, 0..15, color=[blue,red], labels=[processes, speedup], title=Title);

plot({p->1,[[p,T[1]/(p*T[p])] $p=1..15]},1..16, 0..1, color=[blue,red], labels=[processes, "parallel efficiency"], title=Title);