Re: ode45 error: dimension mismatch in line 345 column 17

[Sebastian Schöps]

Hi, 

please keep the mailing list in cc.

> No the Hamil function returns a 3x3 matrix based on the values of X, and it 
> along with every other function works fine in the command line. It seems that 
> for some reason the Delta functions are not returning values when called in 
> ode45, making X=[ ].
> 
> function [ H ] = Hamil( X )
>   H=[X(1)+X(2)-X(3)   -2*X(5)   -2*X(6); -2*X(5)   X(1)-X(2)+X(3)   -2*X(4); 
> -2*X(6)   -2*X(4)   X(2)-X(1)+X(3)];
> endfunction
> 
> Dalton

I tried your functions and they work for me using 
"[t,Y]=ode45(@(t,y)bangodefun(y,t,T,N), [0 1], Y0)". I am using them with 
octave 4.3.0+ on macOS. Maybe you have several incompatible versions in your 
path? 

Sebastian

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Just paste this into the octave window ...
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function dydt=bangodefun(y,t,T,N)
  X=[Delta1(t,T(1:N(1))); Delta2(t,T(N(1)+1:sum(N(1:2)))); 
Delta3(t,T(sum(N(1:2))+1:sum(N(1:3)))); Delta4(t,T(sum(N(1:3))+1:sum(N(1:4)))); 
Delta5(t,T(sum(N(1:4))+1:sum(N(1:5)))); Delta6(t,T(sum(N(1:5))+1:sum(N(1:6))))];
  H=Hamil(X);
  dydt=-i*H*y;
endfunction

function [B1]=Delta1(t,tB1)
  n1=length(tB1);
  tsB1=sort(tB1);
  n=1;
  while n<=n1
    if t<=tsB1(n)
        B1=(1+(-1)^(n))/2;
        n=n1+1;
    elseif t>tsB1(n1)
        B1=mod(n1,2);
        n=n1+1;
    else
        n=n+1;
    end
  end
end

function [B2]=Delta2(t,tB2)
  n2=length(tB2);
  tsB2=sort(tB2);
  n=1;
  while n<=n2
    if t<=tsB2(n)
        B2=(1+(-1)^(n))/2;
        n=n2+1;
    elseif t>tsB2(n2)
        B2=mod(n2,2);
        n=n2+1;
    else
        n=n+1;
    end
  end
end

function [B3]=Delta3(t,tB3)
  n3=length(tB3);
  tsB3=sort(tB3);
  n=1;
  while n<=n3
    if t<=tsB3(n)
        B3=(1+(-1)^(n))/2;
        n=n3+1;
    elseif t>tsB3(n3)
        B3=mod(n3,2);
        n=n3+1;
    else
        n=n+1;
    end
  end
end

function [J1]=Delta4(t,tJ1)
  n4=length(tJ1);
  tsJ1=sort(tJ1);
  n=1;
  while n<=n4
    if t<=tsJ1(n)
        J1=(1+(-1)^(n))/2;
        n=n4+1;
    elseif t>tsJ1(n4)
        J1=mod(n4,2);
        n=n4+1;
    else
        n=n+1;
    end
  end
end

function J2=Delta5(t,tJ2)
  n5=length(tJ2);
  tsJ2=sort(tJ2);
  n=1;
  while (n <= n5)
    if t<=tsJ2(n)
        J2=(1+(-1)^(n+1))/2;
        n=n5+1;
    elseif t>tsJ2(n5)
        J2=-1*(mod(n5,2)-1);
        n=n5+1;
    else
        n=n+1;
    endif
  endwhile
endfunction

function [J3]=Delta6(t,tJ3)
  n6=length(tJ3);
  tsJ3=sort(tJ3);
  n=1;
  while n<=n6
    if t<=tsJ3(n)
        J3=(1+(-1)^(n+1))/2;
        n=n6+1;
    elseif t>tsJ3(n6)
        J3=-1*(mod(n6,2)-1);
        n=n6+1;
    else
        n=n+1;
    endif
  endwhile
endfunction

function [ H ] = Hamil( X )
  H=[X(1)+X(2)-X(3)   -2*X(5)   -2*X(6); -2*X(5)   X(1)-X(2)+X(3)   -2*X(4); 
-2*X(6)   -2*X(4)   X(2)-X(1)+X(3)];
endfunction

T=[0; 0; 0; 0; .28; .56; .28; .56];
N=[1 1 1 1 2 2];
Y0=[1; 0; 0];
[t,Y]=ode45(@(t,y)bangodefun(y,t,T,N), [0 1], Y0)