How to named/called the files: Yi.dat for i=1:nt ?

Hello to all! I tried to use the proposed code for dynamically changing of the file name, but something didn't work. So, the code is (sorry that it is so long) :

      function [Abl3d,F]=timecycle1 
    clear all
      %Geometry
              EJ=849309; m=0.249; M=0.785;U=2.5; 
              Cs=540; Ks=341.4; 
      % Mesh
  dt=0.02; 
  dx=0.5; 
  n=5; 
  NUI=n+2; 

nt=3; % Time level assumed for this exmp=3, but it should be nt=1:17

          Asub=zeros(3,3); Asub(2,2)=-((2*M*U)/dx);  Asub(2,3)=EJ/(dx^2);  Asub(3,2)=-dt/(dx^2);           
          Amd=zeros(3,3); Amd(1,1)=1;Amd(1,2)=-dt; Amd(2,1)=Ks;Amd(2,2)=((2*M*U/dx)+((M+m)/dt)+Cs); Amd(2,3)=(M*(U^2))-(2*EJ/(dx^2));Amd(3,2)=2*dt/(dx^2); Amd(3,3)=1;
          Asup=zeros(3,3); Asup(2,3)=EJ/(dx^2); Asup(3,2)=-dt/(dx^2); 
          Amdg=zeros(3,3); Amdg(1,1)=1;Amdg(1,2)=-dt; Amdg(2,1)=Ks+((2*EJ)/(dx^4)); Amdg(2,2)=((2*M*U/dx)+((M+m)/dt)+Cs);Amdg(2,3)=(M*(U^2))-(2*EJ/(dx^2));Amdg(3,3)=1;
          D=zeros(3,3); D(1,1)=1; D(2,2)=(M+m)/dt; D(3,3)=1;
          K=zeros(3,3);  K(2,1)=Ks; K(2,2)=Cs;
          Gl=zeros(3,3);  Gl(2,1)=2*EJ/(dx^4); Gl(2,2)=2*M*U/dx;Gl(3,2)=dt/(dx^2);
          Gr=zeros(3,3);  Gr(2,1)=2*EJ/(dx^4); Gr(3,2)=dt/(dx^2);
  %%CALLING THE SUBFUNCTION. 
  % (Additional functions within the file are called subfunctions, and these are only visible to the primary function or to other subfunctions in the same file.)
  F = ReadyF; 
  Abl3d = Bl3D;

%%SOLUTION OF THE ALGEBRAIC SYSTEM AND OBTAINING OF THE UNKNOWING VARIABLES FOR THE CURRENT TIME LEVEL
  % time level- nt
  format shortE
Y=Abl3d\F;
disp(Y);
csvwrite('Y.dat',Y); % !!!!! the file names change dynamically with 'nt',i.e. Y1.dat;Y2.dat;... 

%%I.1.Subfunction Bl3D, a subfunction of the main function "combine" that gives the left side of tha algebraic system

function A = Bl3D % Calling "blktridiag" subfunction 

Asub;% the sub-diagonal blocks
Amd; % the main diagonal blocks
Asup; % the super-diagonal blocks
Amdg; % The boundary block,that stands at the beginning and end af the main diagonal
n; %give the size of the blok 3-diag.matrix and is equal to the number of the inner mesh X-node

A = blktridiag(Amd,Asub,Asup,n);
%spy(A)
%full(A)

        %%%I.1.a.Subfunction "blktridiag"
  % It is a subfunction of the "Bl3D" and sub-subfunction of the main function "combine"
  function A = blktridiag(Amd,Asub,Asup,n)
      % BLKTRIDIAG: computes a sparse (block) tridiagonal matrix with n blocks
      % usage: A = BLKTRIDIAG(Amd,Asub,Asup,n)  % identical blocks
      % usage: A = BLKTRIDIAG(Amd,Asub,Asup)    % a list of distinct blocks
  Amdg;
  % Which mode of operation are we in?
  if nargin==4
    % replicated block mode

    % verify the inputs in this mode are 2-d arrays.
    if (length(size(Amd))~=2) || ...
       (length(size(Asub))~=2) || ...
       (length(size(Asup))~=2) 
      error 'Inputs must be 2d arrays if a replication factor is provided'
    end

    % get block sizes, check for consistency
    [p,q] = size(Amd);
    if isempty(Amd)
      error 'Blocks must be non-empty arrays or scalars'
    end
    if any(size(Amd)~=size(Asub)) || any(size(Amd)~=size(Asup)) 
      error 'Amd, Asub, Asup are not identical in size'
    end

    if isempty(n) || (length(n)>1) || (n<1) || (n~=floor(n))
      error 'n must be a positive scalar integer'
    end

    % scalar inputs?
    % since p and q are integers...
    if (p*q)==1
      if n==1
        A = Amd;
      else
        % faster as Jos points out
        A = spdiags(repmat([Asub Amd Asup],n,1),-1:1,n,n);
      end
      % no need to go any farther
      return
    end

    % use sparse. the main diagonal elements of each array are...
    s=repmat(Amdg(:),1,1); % Replicate and tile array
    v=[s;repmat(Amd(:),n-2,1);s]; % Поставяме Amdg в началото и края на гл.диагонал 
    % then the sub and super diagonal blocks.
    if n>1
      % sub-diagonal
      v=[v;repmat(Asub(:),n-1,1)];

      % super-diagonal
      v=[v;repmat(Asup(:),n-1,1)];
    end

elseif nargin==3
  % non-replicated blocks, supplied as planes of a 3-d array

    % get block sizes, check for consistency
    [p,q,n] = size(Amd);
    if isempty(Amd)
      error 'Blocks must be (non-empty) arrays or scalars'
    end

    if (p~=size(Asub,1)) || (q~=size(Asub,2)) || (p~=size(Asup,1)) || (q~=size(Asup,2))
      error 'Amd, Asub, Asup do not have the same size blocks'
    end

    if (n>1) && (((n-1) ~= size(Asub,3)) || ((n-1) ~= size(Asup,3)))
      error 'Asub and Asup must each have one less block than Amd'
    end

    % scalar inputs?
    if (p*q)==1
      if n==1
        A = Amd(1);
      else
        % best to just use spdiags
        A = spdiags([[Asub(:);0], Amd(:), [0;Asup(:)]],-1:1,n,n);
      end
      % no need to go any farther
      return
    end

    % The main diagonal elements
    v = Amd(:);
    % then the sub and super diagonal blocks.
    if n>1
      % sub-diagonal
      v=[v;Asub(:)];

      % super-diagonal
      v=[v;Asup(:)];
    end
  else
    % must have 3 or 4 arguments
    error 'Must have either 3 or 4 arguments to BLKTRIDIAG'
  end

% now generate the index arrays. first the main diagonal
[ind1,ind2,ind3]=ndgrid(0:p-1,0:q-1,0:n-1);
rind = 1+ind1(:)+p*ind3(:);
cind = 1+ind2(:)+q*ind3(:);
% then the sub and super diagonal blocks.
if n>1
  % sub-diagonal
  [ind1,ind2,ind3]=ndgrid(0:p-1,0:q-1,0:n-2);
  rind = [rind;1+p+ind1(:)+p*ind3(:)];
  cind = [cind;1+ind2(:)+q*ind3(:)];

    % super-diagonal
    rind = [rind;1+ind1(:)+p*ind3(:)];
    cind = [cind;1+q+ind2(:)+q*ind3(:)];
  end
  % build the final array all in one call to sparse
  A = sparse(rind,cind,v,n*p,n*q);
  end
  end
  %%I.2.Subfunction ReadyF, Bl3D is a subfunction of the main function "combine" and gives the right side of the algebraic system
  function F3 = ReadyF
  global Ugd Vgd Ypred; 
  load 'Ypred.dat'
  load 'Ugd.dat'
  load 'Vgd.dat'
  n; NUI; D;
  Y=Ypred; 
  y=reshape(Y,3,[]); 
  Dy=D*y; 
  format long
    Gl; Gr; K;

i=1;  
    ugvg1=[ Ugd(nt,i);Vgd(nt,i);0];
       Glugvg1=Gl*ugvg1;
       Gld=Dy(:,1)+Glugvg1; 

i=NUI;
        ugvgNUI=[Ugd(nt,i);Vgd(nt,i);0];
        GrugvgNUI=Gr*ugvgNUI;
        Grd=Dy(:,n)+GrugvgNUI;

ugvg=zeros(3,1);
for i=2:NUI-1
    ii=i-1; 
    iii=3*ii; 
    ugvg(:,ii)=[Ugd(nt,i);Vgd(nt,i);0]; 
end;
  Kugvg=K*ugvg;
  FKugvg=reshape(Kugvg,[iii 1]); 
  F2=FKugvg; 

Dy1=Dy; 
Dy1(:,1)=[];
Dy2=Dy1;
Dy2(:,n-1)=[];
a=3*n-6; 
Dy3=reshape(Dy2,[a 1]);
F1=[Gld;Dy3;Grd];
F3=F1+F2; 
end
end

P.S. The code will need 3 external data files, should I post or send them? The line 31-33 contain the information and the question? I hope that you will be able to understand.

In fact, there is something more. If you run the code you will see the it produces one unwanted variable "ans=" , which I want to suppress?

Thank you again and excuse me for the heavy code, but I'm not sure that with a sample short one the question would be clear ask!!! Regards

Answer 1

[Matt Kindig]

I didn't go through the entire code, but I think you want the line to be:

csvwrite(['Y', num2str(nt), '.dat'],Y);

By the way, the 'ans' that appears is because you have a command that is not terminated by a semicolon. I can't seem to find it right now, however.

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

[D.Chehov]

Thank you very much about the useful code and the whole information.

About the appearance of "ans", I've checked very carefully every line in the code for termination with semicolon. In addition, if somewhere the semicolon is omitted Matlab dusplays a warning message. So the problem is somewhere else and will keep looking on it, any suggestions are highly appreciated!

Regards

[Jan]

Accepting an answer means, that the problem is solved.

Answer 2

[Jan]

You can find the line, which causes the "ans =" output by using the debugger. Simply step through the code line by line until the "ans " appears.

There are several strange lines, which do not have any effect:

n; NUI; D;
...
Asub;
Amd;
Asup;
Amdg;
n;
...
Gl; Gr; K;

What do you want to achieve with such lines? I think beside confusing the reader they are useless.

Starting a function by clear all is a waste of time without any advantage. This command clear all variables in the current workspace (but there are no variables in a function without inputs) and it removes all loaded functions from the memory. Reloading and parsing a functions need a lot of time, therefore a clear all can reduce the speed dramatically.

It is not clear which are the lines 31 to 33.

The variable iii is not used inside the for i=2:NUI-1 loop, so it would be faster and cleaner to move the calculation out of the loop.

[D.Chehov]

Dear, Jan,

thank you for your time and for the comments on the code! I will remove "clear all" to save time, thank you!

I accepted the answer because it is really useful and sorry about the comments on "ans". Finally I've found out what line produces "ans=" .....the name of the function "[Abl3d,F]=timecycle1". I don't know the reason, but I will try to find it in the MatLab help.

About the stranger lines, I think that they are needed because more than one function is presented in the code.... :(

Now, I will try to prepare an example of my next question...I have a lot, that's why I really appreciate the opinions and understanding in this forum!

[Matt Kindig]

How do you call the function? If you call it at the command line, i.e.

>> timecycle1 %note no semicolon here

then the first output of the function will be assigned to the variable 'ans' and output to the command window.

[D.Chehov]

Yes, you are right, thanks!