How can i correct this error ?

Hi

My problem is about a three node cantilever beam. I do a program that estimate the mass and stiffness matrix. c is an

output variable.

But, i obtain this error

Undefined function or variable "c". Error in fe_mk (line 79) if length(c)~=0 Error in prog_principle (line 31) [m,k,mdof]= fe_mk(node,elt,pl,il)

My priniciple program is :

format long g;

format compact;

% node# unused x y z

node=[1 0 0 0 0 0 0;

      2    0 0 0       25.4e-03     0          0;

      3    0 0 0       50.8e-03     0          0;

      4    0 0 0       1            1          1];

elt=[

%declaration of elemnt groupe

    Inf abs('beam1')

 %node1   node2    pl     il     refnode

   1       2       1      1          4       0    %longerons

   2       3       1      1          4       0];

% matid matType E nu rho

pl=[ 1 1 10.5e+10 3.4e-01 9e+03];

% secId SecType J i1 i2 A

il=[ 1 1 3.75e-10 7.27e-15 3.75e-10 4.452e-06 ]; %longerons

%call of function

[m,k,mdof]= fe_mk(node,elt,pl,il)

And the fe_mk funtion is :

function [m,k,mdof]=fe_mk(node,elt,pl,il)

 NNode = zeros(max(node(:,1)),1);NNode(node(:,1))=(1:length(node(:,1)))';

 if     nargin==4               ty='mka';mode=[];adof=[];

 elseif nargin==7 && opt(1)==2  ty='ene';

 elseif nargin==7 && opt(1)==1  ty='dmk';

 elseif nargin==7 && opt(1)==0  ty='mka';

 else  disp ('not a valid value for opt(1)');

 end

 EGroup = [find(elt(:,1)==Inf)' size(elt,1)+1];

 nGroup = length(EGroup)-1;nM=size(mode,2);nA=length(adof);

 if strcmp(ty,'mka')&& nM==0

   k = spalloc(size(node,1)*6,size(node,1)*6,size(elt,1)*100);

   m = spalloc(size(node,1)*6,size(node,1)*6,size(elt,1)*100);

   if nargout==4

    c = spalloc(size(node,1)*6,size(node,1)*6,size(elt,1)*100);

   end

 elseif strcmp(ty,'mka')&& nM~=0

   k = zeros(nM); m = zeros(nM);

   if nargout == 4    c = zeros(nM); end

 elseif strcmp(ty,'ene')&& nM~=0

   m=zeros(size(elt,1),nM);

   if nargout==2 c=m;end

 elseif strcmp(ty,'ene')&& nM==0

   error('Cannot compute energies without a mode');

 elseif strcmp(ty,'dmk') &&  nM==0

   if nA==0 error('adof is empty, cannot assemble group stiffness'); end

   k = spalloc(nA*nGroup,nA,size(elt,1)*100);m=k;

   if nargout == 4    c = k; end

 elseif strcmp(ty,'dmk') && nM~=0

   k = zeros(nM*nGroup,nM); m = k;

   if nargout == 4    c = k; end

 end

mdof = [];EDof = [];

if nGroup == 0 % backward compatibility for beam only model

elt = [Inf abs('beam1') zeros(1,size(elt,2)-6);

elt zeros(size(elt,1),size(elt,2)-6)];

nGroup = 1;EGroup = [find(elt(:,1)==Inf)' size(elt,1)+1];

end

% ----------------------------------------------------------------------------

% loop over element groups

for jGroup = 1:nGroup

ElemF = [find(elt(EGroup(jGroup),:)==0) size(elt,2)+1];

ElemF = deblank(setstr(elt(EGroup(jGroup),2:ElemF(1)-1)));

cEGI = EGroup(jGroup)+1:EGroup(jGroup+1)-1;

if exist(ElemF)==2

   eval(['eCall=' ElemF '(1);'],'eCall=[];');

else eCall=[];end

for jElt=1:length(cEGI)

if exist(ElemF)==2

   if isempty(eCall) 

         eval(['[m1,k1,i1] = ' ElemF ...

         '(node,elt(cEGI(jElt),:),pl,il,[1 jGroup jElt]);']);

   else eval([eCall ';'])

   end

else disp([ElemF ' : unkwown element function']);

end

% --------------------------------------------------------------------------

if strcmp(ty,'mka')

if isempty(adof)

%aa=clock;

ind = zeros(length(i1),1);for j2 = 1:length(i1)

           i2 = find(mdof==i1(j2));

           if isempty(i2)  mdof = [mdof;i1(j2)];ind(j2)=length(mdof);

           else            ind(j2) = i2;   end

      end

%bb=[etime(clock,aa)];aa=clock;

k(ind,ind)=k(ind,ind)+k1;

m(ind,ind)=m(ind,ind)+m1;

if length(c)~=0

          c(ind,ind)=c(ind,ind)+c1; end

else % selection of DOFs

in1=[];in2=[];for j2 = 1:length(i1)

           i2 = find(mdof==i1(j2));

           if isempty(i2)

i2 = find(adof==i1(j2));

if isempty(i2) i2=find(abs(adof-rem(i1(j2),1))<1e-7); end

if isempty(i2) i2=find(adof==fix(i1(j2))); end

                if ~isempty(i2)

       mdof = [mdof;i1(j2)];in1=[in1 length(mdof)];in2=[in2 j2];

end

           else  in1=[in1 i2];in2=[in2 j2];   end

          end

k(in1,in1) = k(in1,in1)+k1(in2,in2);

m(in1,in1) = m(in1,in1)+m1(in2,in2);

if isempty(c) c(in1,in1) = c(in1,in1)+c1(in2,in2);end

end

        if rem(cEGI(jElt),100)==0

           disp(['Done ' num2str(cEGI(jElt)) ' elements']);

        end

elseif strcmp(ty,'ene')

ind = zeros(length(i1),1);

for j2 = 1:length(i1) ind(j2) = find(adof==i1(j2)); end

in2 = find(ind~=0); ind = ind(in2);

if ~isempty(ind);for j2 = 1:size(mode,2);

if nargout>0

m(cEGI(jElt),j2) = mode(ind,j2)'*k1(in2,in2)*mode(ind,j2);

end

if nargout>1

c(cEGI(jElt),j2) = mode(ind,j2)'*m1(in2,in2)*mode(ind,j2);

end

end;end

        if rem(cEGI(jElt),100)==0

         disp(['Done ' num2str(cEGI(jElt)) ' elements']);

        end

elseif strcmp(ty,'dmk')

ind = zeros(length(i1),1);

for j2 = 1:length(i1) ind(j2) = find(adof==i1(j2)); end

in2 = find(ind~=0); ind = ind(in2); if nM~=0 % projection of a basis of modes

k(jGroup*nM+[-nM+1:0],:) = k(jGroup*nM+[-nM+1:0],:) + ...

mode(ind,:)'*k1(in2,in2)*mode(ind,:);

m(jGroup*nM+[-nM+1:0],:) = m(jGroup*nM+[-nM+1:0],:) + ...

mode(ind,:)'*m1(in2,in2)*mode(ind,:);

if length(c)~=0

c(jGroup*nM+[-nM+1:0],:) = c(jGroup*nM+[-nM+1:0],:) + ...

mode(ind,:)'*c1(in2,in2)*mode(ind,:);

          end

else % no projection

in3 = ind+nA*(jGroup-1);

m(in3,ind) = m(in3,ind)+ m1(in2,in2);

k(in3,ind) = k(in3,ind)+ k1(in2,in2);

if length(c)~=0 c(in3,ind) = c(in3,ind)+ c1(in2,in2);end

end

        if rem(cEGI(jElt),100)==0

             disp(['Done ' num2str(cEGI(jElt)) ' elements']);

        end

end

end

% ----------------------------------------------------------------------------

end; % end loop on element groups

if strcmp(ty,'ene')

m=full(m(1:size(elt,1),1:size(mode,2)));

if nargout>1 c=full(c(1:size(elt,1),1:size(mode,2))); end

k=[];mdof=[];

elseif strcmp(ty,'mka')

[mdof,i1]=sort(mdof); [EDof,i2]=sort(EDof); i1 = [i1;i2];

k = k(i1,i1); m = m(i1,i1);

if ~isempty(c) c = c(i1,i1); end

mdof = [mdof;EDof];

if nargout==2 m=k;c=mdof; end

if nargout==3 c=k;k=mdof; end

elseif strcmp(ty,'dmk')

mdof = adof;

if nargout==2 m=k;c=mdof; end

if nargout==3 c=k;k=mdof; end

end