Vectors and Scalars in function calls

Hi there,

I'm making another reverb function, where I'd like the input to include room dimensions (L, a 1x3 vector) and a scalar, N.

For the vector, I then extract the length of each dimension (Lx=L(1), Ly=L(2) etc) in the following code. The problem is, I have tried making this function, is_reverb(L,N) accept these values and I keep getting errors.

So I guess my question is if it is possible to do a function call taking a vector for one variable and a scalar for another?

[Honglei Chen]

MATLAB can definitely handle that. Can you show the error?

Answer 1

[Wayne King]

That's correct Craig, you save that imagesource.m file somewhere on the MATLAB search path then define your L vector in the workspace as well as your N

>> L  = [20 10 8];
>> N = 50;

and then call

>>h =imagesource(N,L);

[C Meek]

Thanks!

Answer 2

[Wayne King]

You can do definitely do that. It would help a lot if you posted the code (using formatting) and the errors you are getting.

Answer 3

[C Meek]

Certainly.

function [h]=imagesource(N,L);

Lx=L(1);Ly=L(2);Lz=L(3); %Room Dimensions

S=[50 50 25];
p=S(1); q=S(2); r=S(3); %Source

R=[1 1 1.8];
a=R(1); b=R(2); c=R(3); %Receiver

alpha=0.8; %absorption coefficient

%N=10;

Fs=44100; 

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

tf=sqrt((N*Lx+p-a)^2+(N*Ly+q-b)^2+(N*Lz+r-c)^2)/343; %last arriving impulse
h=zeros(1,ceil(tf*Fs)); %impulse response vector

for d=-N:N

      if mod(d,2)==1
      A_d=(d+1)*Lx-p-a;
      else
      A_d=d*Lx+p-a;
      end

      for e=-N:N

          if mod(e,2)==1
          B_e=(e+1)*Ly-q-b;
          else
          B_e=e*Ly+q-b;
          end

          for f=-N:N

              if mod(f,2)==1;
              C_f=(f+1)*Lz-r-c;
              else
              C_f=f*Lz+r-c;
              end

              l_def=sqrt((A_d^2+B_e^2+C_f^2)); %distance
              w=abs(d)+abs(e)+abs(f); %number of reflections
              g=(1/l_def)*alpha^w; %magnitude
              t=l_def/343; %time

              k=ceil(t*Fs);

              h(k+1)=g; %updating impulse response vector
          end

      end

end

plot(h);

wavwrite(h,Fs,'h');
disp('Impulse Response File Write Successful!')

end

Sorry for the length, but I wouldn't worry too much about the stuff in the for loops. As you can probably deduce I have a similar ideas for the vectors S and R - I just haven't tried to move them into the function call yet.

Actually, I've just run the code again and got no errors so I think I'm ok. So you simply pre-define a vector and scalar and just read them into the function call as normal?

Thanks

Craig