How to take 100 samples of a plot.
Show older comments
I have a task to take 100 samples of a plot at a fixed value of parameters a2, omega1, and omega2 and I will be changing a1 and take 100 samples. It consumes so much time so I am wondering is their a way to take a 100 samples of a plot.
clear all; close all; clc;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Simulation %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%avgnum=10;
%for avg=1:avgnum
OMEGA1= 1:0.2:6.4;
OMEGA2= 6.6:0.2:12;
%Erroravg_nonzero_x1_y1=zeros([1,length(OMEGA1)]);
%Erroravg_zero_x1_y1=zeros([1,length(OMEGA1)]);
%Erroravg_nonzero_x2_y2=zeros([1,length(OMEGA2)]);
%Erroravg_zero_x2_y2=zeros([1,length(OMEGA2)]);
for num1=1:length(OMEGA1)
for num2=1:length(OMEGA2)
%value of constants
a1=0.2;a2=0.3;
%omega1=5;omega2=4;
omega1=OMEGA1(num1);
omega2=OMEGA2(num2);
%omega1= 1:0.5:10;
%omega2= 11:0.5:20;
G=1;C12=0.01;C21=0.02;
dt=0.01; %step size
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
x1(1)=0.5;
y1(1)=0.5;
x2(1)=1;
y2(1)=1;
for i=2:1000
x1(i)=x1(i-1)+((a1-x1(i-1)^2-y1(i-1)^2)*x1(i-1)-omega1*y1(i-1)+G*C12*(x2(i-1)-x1(i-1)))*dt;
y1(i)=y1(i-1)+((a1-x1(i-1)^2-y1(i-1)^2)*y1(i-1)+omega1*x1(i-1)+G*C12*(y2(i-1)-y1(i-1)))*dt;
x2(i)=x2(i-1)+((a2-x2(i-1)^2-y2(i-1)^2)*x2(i-1)-omega2*y2(i-1)+G*C21*(x1(i-1)-x2(i-1)))*dt;
y2(i)=y2(i-1)+((a2-x2(i-1)^2-y2(i-1)^2)*y2(i-1)+omega2*x2(i-1)+G*C21*(y1(i-1)-y2(i-1)))*dt;
end
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Observation %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Ndatamin=4;Ndatamax=31;
Data=Ndatamin:1:Ndatamax;
Data=Data/Ndatamax;
Error_nonzero_x1=zeros([1,Ndatamax-Ndatamin+1]);%initialization
Error_zero_x1=zeros([1,Ndatamax-Ndatamin+1]);%initialization
Error_zero_y1=zeros([1,Ndatamax-Ndatamin+1]);%initialization
Error_nonzero_x2=zeros([1,Ndatamax-Ndatamin+1]);%initialization
Error_zero_x2=zeros([1,Ndatamax-Ndatamin+1]);%initialization
Error_nonzero_y2=zeros([1,Ndatamax-Ndatamin+1]);%initialization
Error_zero_y2=zeros([1,Ndatamax-Ndatamin+1]);%initialization
count=0;
for N_m=Ndatamin:Ndatamax
count=count+1;
N_measurements=N_m;
N_basis=31;
%index=randi([20000,30000],1,N_m);
index=randi([100,499],1,N_m);
Xdot1=zeros([1,N_measurements]);
Ydot1=zeros([1,N_measurements]);
Xdot2=zeros([1,N_measurements]);
Ydot2=zeros([1,N_measurements]);
for ni=1:N_measurements
Xdot1(ni)=(x1(index(ni)+1)-x1(index(ni)))/dt;
Ydot1(ni)=(y1(index(ni)+1)-y1(index(ni)))/dt;
Xdot2(ni)=(x2(index(ni)+1)-x2(index(ni)))/dt;
Ydot2(ni)=(y2(index(ni)+1)-y2(index(ni)))/dt;
end
M=zeros([N_measurements,N_basis]);
for i=1:N_measurements
for j=1:N_basis
if j==1
M(i,j)=1;
elseif j==2
M(i,j)=x1(index(i));
elseif j==3
M(i,j)=y1(index(i));
elseif j==4
M(i,j)=x2(index(i));
elseif j==5
M(i,j)=y2(index(i));
elseif j==6
M(i,j)=x1(index(i))^2;
elseif j==7
M(i,j)=x2(index(i))^2;
elseif j==8
M(i,j)=y1(index(i))^2;
elseif j==9
M(i,j)=y2(index(i))^2;
elseif j==10
M(i,j)=x1(index(i))*x2(index(i));
elseif j==11
M(i,j)=x1(index(i))*y1(index(i));
elseif j==12
M(i,j)=x1(index(i))*y2(index(i));
elseif j==13
M(i,j)=x2(index(i))*y1(index(i));
elseif j==14
M(i,j)=x2(index(i))*y2(index(i));
elseif j==15
M(i,j)=y1(index(i))*y2(index(i));
elseif j==16
M(i,j)=x1(index(i))^3;
elseif j==17
M(i,j)=y1(index(i))^3;
elseif j==18
M(i,j)=x2(index(i))^3;
elseif j==19
M(i,j)=y2(index(i))^3;
elseif j==20
M(i,j)=x1(index(i))^2*x2(index(i));
elseif j==21
M(i,j)=x1(index(i))^2*y1(index(i));
elseif j==22
M(i,j)=x1(index(i))^2*y2(index(i));
elseif j==23
M(i,j)=x2(index(i))^2*x1(index(i));
elseif j==24
M(i,j)=x2(index(i))^2*y1(index(i));
elseif j==25
M(i,j)=x2(index(i))^2*y2(index(i));
elseif j==26
M(i,j)=y1(index(i))^2*x1(index(i));
elseif j==27
M(i,j)=y1(index(i))^2*x2(index(i));
elseif j==28
M(i,j)=y1(index(i))^2*y2(index(i));
elseif j==29
M(i,j)=y2(index(i))^2*x1(index(i));
elseif j==30
M(i,j)=y2(index(i))^2*x2(index(i));
else
M(i,j)=y2(index(i))^2*y1(index(i));
end
end
end
end
figure
hold on
plot(x1,'r')
plot(x2,'g')
Accepted Answer
First, what are you actually doing with M, Xdot1, etc.? Currently, the code overwrites them each N_m loop, without doing anything with the results
Try this: define sampled vectors, so you can later vectorize things:
index=randi([100,499],1,N_m);
x1_samp0 = x1(index);
x1_samp1 = x1(index+1);
...
Xdot1=(x1_samp1-x1_samp0)/dt;
...
M(:,1)=1;
M(:,2)=x1_samp0;
...
M(:,6)=x1_samp0.^2;
edit: changed my mind on other option; don't do it. Here are some general tips, though:
- if you have a set of conditions that can be expressed as variable=first, variable=second, etc. -- use a switch instead of if-elseif
- If you have a loop running over a set of conditions and operations which have nothing else in common -- just run each line individually, then fill in the "else" portion after
for j=1:N_basis
if j==1
M(i,j)=1;
elseif j==2
M(i,j)=x1(index(i));
elseif j==3
M(i,j)=y1(index(i));
end
end
does the same as the below, but cleaner and faster:
M(i,1)=1;
M(i,2)=x1(index(i));
M(i,3)=y1(index(i));
- many, many, many for loops can be replaced with vector operations. It's kinda the point of Matlab
More Answers (0)
Categories
Find more on Loops and Conditional Statements in Help Center and File Exchange
