MATLAB error 'index exceeds matrix dimensions'

hello all

i want to run this function but i got index exceeds, i checked my loops but i could not saw the error.

where vn=vs=1 and M=100 and th1=1000 and Dr1=D1=0

function D=distortion(vn,vs,M,th1,x,y,Dr1,D1);
for i=1:M;
    for j=1:M;
        if i~=j 
 d1(i,j)=sqrt(((y(j)-y(i))^2+(x(j)-x(i))^2));

Dr1=exp(-d1(i,j)/th1)+Dr1;
        end 
    end
end
for i=1:M
    ds1(i)=sqrt(((y(j)-0)^2+(x(j)-0)^2));% point source at 0 0
cor2=exp(-ds1(i)/th1);
D1=cor2+D1;
end
 D=(vs^2)-((vs^4)/(M*((vs^2)+(vn^2))))*(2*(D1-1))+((vs^6)/((M^2)*((vs^2)+(vn^2)))*Dr1);
end

Answer 1

[Image Analyst]

This worked for me.

function test1
vn=1
vs=1 ;
M=100 ;
th1=1000;
Dr1=0;
D1=0
y = rand(1,M);
x = rand(1,M);
D=distortion(vn,vs,M,th1,x,y,Dr1,D1)
end

function D=distortion(vn,vs,M,th1,x,y,Dr1,D1)
for i=1:M;
  for j=1:M;
    if i~=j
      d1(i,j)=sqrt(((y(j)-y(i))^2+(x(j)-x(i))^2));
      
      Dr1=exp(-d1(i,j)/th1)+Dr1;
    end
  end
end
for i=1:M
  ds1(i)=sqrt(((y(j)-0)^2+(x(j)-0)^2));% point source at 0 0
  cor2=exp(-ds1(i)/th1);
  D1=cor2+D1;
end
D=(vs^2)-((vs^4)/(M*((vs^2)+(vn^2))))*(2*(D1-1))+((vs^6)/((M^2)*((vs^2)+(vn^2)))*Dr1);
end

What did you pass in for X and Y?

[ali]

,x=rand(1,100); y=rand(1,100);

[ali]

i just run it now but same error

[Walter Roberson]

Which line did you receive the error on?

[ali]

when i run this thing alone i got error

vn=1
vs=1 ;
M=100 ;
th1=1000;
Dr1=0;
D1=0
y = rand(1,M);
x = rand(1,M);
D=distortion(vn,vs,M,th1,x,y,Dr1,D1)

but when i run this

function test1
vn=1
vs=1 ;
M=100 ;
th1=1000;
Dr1=0;
D1=0
y = rand(1,M);
x = rand(1,M);
D=distortion(vn,vs,M,th1,x,y,Dr1,D1)
end

there is no error will be

and i want the first one

[Walter Roberson]

We need the error message, everything in red.

[ali]

when i call this function alone i did not get any error but when i call it in my main program with other functions i got index issues

[Walter Roberson]

We need the error message that you do get.

My guess is that you defined a variable named "distortion", and that is interfering with your ability to call the function named "distortion".

[Image Analyst]

Is there something about "We need the error message, everything in red." that you don't understand? Help us to help you.

[ali]

i got this red error .. Index exceeds matrix dimensions.. all my other variables are independent from this function

[ali]

when i just use this prog alone in my main program no error will appear but when i use the function i got matrix index issues

for i=1:M;
  for j=1:M;
    if i~=j
      d1(i,j)=sqrt(((y(j)-y(i))^2+(x(j)-x(i))^2));
      
      Dr1=exp(-d1(i,j)/th1)+Dr1;
    end
  end
end
for i=1:M
  ds1(i)=sqrt(((y(j)-0)^2+(x(j)-0)^2));% point source at 0 0
  cor2=exp(-ds1(i)/th1);
  D1=cor2+D1;
end
D=(vs^2)-((vs^4)/(M*((vs^2)+(vn^2))))*(2*(D1-1))+((vs^6)/((M^2)*((vs^2)+(vn^2)))*Dr1);

[Walter Roberson]

We need a screen capture of the error message. Do not just tell us that it happens, we need to SEE it.

[ali]

here

[Walter Roberson]

Look at your comment about here you apply VQ function. Look at the next line of code. What variable names have you used on the left hand side of the assignment?

[ali]

yes i used distortion variable.. its worked now i changed it .... thxxxx too much

[Walter Roberson]

You see the importance of showing us the actual error instead of just saying that you get an error somewhere?

[ali]

yes u r right