Mein Problem liegt bei der ersten Zeile, er will symbolic variable deklarieren aber macht 'syms s' anstatt syms s.
und zweite Frage was passiert eigentlich in der For-schleife? welche syntax ist in der eckigen Klammern?
du solltest dir ansehen, was nach der for-Schleife mit SymString gemacht wird. Es würde mich nicht wundern, wenn der Befehl in der for-Schleife zusammengesetzt und dann mit EVAL ausgewertet wird.
[a, b] oder [a b] fügt die Operanden a und b durch Nebeneinandersetzen zusammen.
Wenn man dir noch weiter helfen soll, müsste man wissen, wie die Variable Element definiert wird und was anschließend tatsächlich mit SymString gemacht wird.
vielen dank für die Antwort. Meine erste Frage war die Deklaration des symbolic variable. Warum SymString = 'syms s' anstatt SymString = syms s
Ich habe nirgendwo solche symbolic variable Deklaration mit Einführungsstrich gesehen.
Zweitens die syntax [a b ' '] heißt dass, es b in a als String einfügst?
Element ist ein structure Array, was oben deklariert wurde.
Code:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Algorithm for symbolic analysis of circuit with state space matrixes. %% % This Programm take a Pspice netlist,parse it and give the state space %% % matrixes of the system, also the matrix transfert function %% % %%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
disp(sprintf('\n\nStarted -- please be patient.\n'));
[Name N1 N2 arg3]=textread('C:\Program Files\Orcad\PSpice\reihenschwingskreis1-schematic1.net','%s %s %s %s ','headerlines',1);
tic
%Initialize
numElem=0; %Number of passive elements.
numV=0; %Number of independent voltage sources
numO=0; %Number of op amps
numI=0; %Number of independent current sources
numNode=0; %Number of nodes, not including ground (node 0).
%Parse the input file
for i=1:length(Name),
switch(Name{i}(1)),
case{'R','L','C'},
numElem=numElem+1;
Element(numElem).Name=Name{i};
Element(numElem).Node1=str2num(N1{i});
Element(numElem).Node2=str2num(N2{i});
try
Element(numElem).Value=str2num(arg3{i});
catch
Element(numElem).Value=nan;
end case 'V',
numV=numV+1;
Vsource(numV).Name=Name{i};
Vsource(numV).Node1=str2num(N1{i});
Vsource(numV).Node2=str2num(N2{i});
try
Vsource(numV).Value=str2num(arg3{i});
catch
Vsource(numV).Value=nan;
end case 'O',
numO=numO+1;
Opamp(numO).Name=Name{i};
Opamp(numO).Node1=str2num(N1{i});
Opamp(numO).Node2=str2num(N2{i});
Opamp(numO).Node3=str2num(arg3{i});
case 'I'
numI=numI+1;
Isource(numI).Name=Name{i};
Isource(numI).Node1=str2num(N1{i});
Isource(numI).Node2=str2num(N2{i});
try
Isource(numI).Value=str2num(arg3{i});
catch
Isource(numI).Value=nan;
end end
numNode=max(str2num(N1{i}),max(str2num(N2{i}),numNode));
end
%Preallocate all of the cell arrays #################################
G=cell(numNode,numNode);
V=cell(numNode,1);
I=cell(numNode,1);
if((numV+numO)~=0),
B=cell(numNode,numV+numO);
C=cell(numV+numO,numNode);
D=cell(numV+numO,numV+numO);
E=cell(numV+numO,1);
J=cell(numV+numO,1);
end
%Done preallocating cell arrays -------------------------------------
%Fill the G matrix ##################################################
%Initially, make the G Matrix allzeros.
[G{:}]=deal('0');
%Nowfill the G matrix with conductances from netlist
for i=1:numElem,
n1=Element(i).Node1;
n2=Element(i).Node2;
%Make up a string with the conductance of current element.
switch(Element(i).Name(1)),
case 'R',
g = ['1/' Element(i).Name];
case 'L',
g = ['1/s/' Element(i).Name];
case 'C',
g = ['s*' Element(i).Name];
end
%If neither side of the element is connected to ground
%then subtract it from appropriate location in matrix.
if(n1~=0) & (n2~=0),
G{n1,n2}=[ G{n1,n2} '-' g];
G{n2,n1}=[ G{n2,n1} '-' g];
end
%If node 1is connected to graound, add element to diagonal
%of matrix.
if(n1~=0),
G{n1,n1}=[ G{n1,n1} '+' g];
end
%Ditto for node 2.
if(n2~=0),
G{n2,n2}=[ G{n2,n2} '+' g];
end
%Go to next element.
% i=i+4; end
%The G matrix is finished -------------------------------------------
%Fill the I matrix ##################################################
[I{:}]=deal('0');
for j=1:numNode,
for i=1:numI,
if(Isource(i).Node1==j),
I{j}=[I{j} '-' Isource(i).Name];
elseif(Isource(i).Node2==j),
I{j}=[I{j} '+' Isource(i).Name];
end end end
%The I matrix is done -----------------------------------------------
%Fill the V matrix ##################################################
for i=1:numNode,
V{i}=['v_' num2str(i)];
end
%The V matrix is finished -------------------------------------------
if((numV+numO)~=0),
%Fill the B matrix ##################################################
%Initially, fill with zeros.
[B{:}]=deal('0');
%First handle the case of the independent voltage sources.
for i=1:numV, %Go through each independent source.
for j=1:numNode %Go through each node.
if(Vsource(i).Node1==j), %If node is first node,
B{j,i}='1'; %then put '1' in the matrices.
elseif(Vsource(i).Node2==j), %If second node, put -1.
B{j,i}='-1';
end end end
%Now handle the case of the Op Amp
for i=1:numO,
for j=1:numNode
if(Opamp(i).Node3==j),
B{j,i+numV}='1';
else
B{j,i+numV}='0';
end end end
%The B matrix is finished -------------------------------------------
%Fill the C matrix ##################################################
%Initially, fill with zeros.
[C{:}]=deal('0');
%First handle the case of the independent voltage sources.
for i=1:numV, %Go through each independent source.
for j=1:numNode %Go through each node.
if(Vsource(i).Node1==j), %If node is first node,
C{i,j}='1'; %then put '1' in the matrices.
elseif(Vsource(i).Node2==j), %If second node, put -1.
C{i,j}='-1';
end end end
%Now handle the case of the Op Amp
for i=1:numO,
for j=1:numNode
if(Opamp(i).Node1==j),
C{i+numV,j}='1';
elseif(Opamp(i).Node2==j),
C{i+numV,j}='-1';
else
C{i+numV,j}='0';
end end end
%The C matrix is finished ------------------------------------------
%Fill the D matrix ##################################################
%The D matrix is non-zero only for CCVS and VCVS (not included
%in this simple implementation of SPICE) [D{:}]=deal('0');
%The D matrix is finished -------------------------------------------
%Fill the E matrix ##################################################
%Start with allzeros [E{:}]=deal('0');
for i=1:numV,
E{i}=Vsource(i).Name;
end
%The E matrix is finished -------------------------------------------
%Fill the J matrix ##################################################
for i=1:numV,
J{i}=['I_' Vsource(i).Name];
end for i=1:numO,
J{i+numV}=['I_' Opamp(i).Name];
end
%The J matrix is finished -------------------------------------------
end %if((numV+numO)~=0)
%Form the A, X, and Z matrices (As cell arrays of strings).
if((numV+numO)~=0),
Acell=[deal(G) deal(B); deal(C) deal(D)];
Xcell=[deal(V); deal(J)];
Zcell=[deal(I); deal(E)];
else
Acell=[deal(G)];
Xcell=[deal(V)];
Zcell=[deal(I)];
end
%Declare symbolic variables #########################################
%This next section declares all variables used as symbolic variables.
%Make "s" a symbolic variable
SymString= 'syms s';
%SymString= ' ';
%Add each of the passive elements to the list of symbolic variables.
for i=1:numElem,
SymString=[SymString Element(i).Name ' '];
end
%Add each element of matrix J and E to the list of symbolic variables.
for i=1:numV,
SymString=[SymString J{i} ' '];
SymString=[SymString E{i} ' '];
end
%Add each opamp output to the list of symbolic variables.
for i=1:numO,
SymString=[SymString J{i+numV} ' '];
end
%Add independent current sources to the list of symbolic variables.
for i=1:numI,
SymString=[SymString Isource(i).Name ' '];
end
%Add independent voltage sources to list of symbolic variables.
for i=1:numNode,
SymString=[SymString V{i} ' '];
end
%Evaluate the string with symbolic variables
eval(SymString);
%Done declaring symbolic variables ----------------------------------
%Create the variables A, X, and Z ###################################
%Right now the matrices Acell, Xcell and Zcell holdcell arrays of
%strings. These must be converted to a symbolic array. Thisis
%accompplished by creating strings that represent the assignment of
%the symbolic arrays, and then evaluating these strings.
%Create assignments for three arrays
Astring='A=[';
Xstring='X=[';
Zstring='Z=[';
for i=1:length(Acell), %for each row in the arrays.
for j=1:length(Acell), %for each column in matrix A.
Astring=[Astring ' ' Acell{i,j}]; %Get element from Acell
end
Astring=[Astring ';']; %Mark end of row with semicolon
Xstring=[Xstring Xcell{i} ';']; %Enter element into array X;
Zstring=[Zstring Zcell{i} ';']; %Enter element into array Z;
end
Astring=[Astring '];']; %Close array assignment.
Xstring=[Xstring '];'];
Zstring=[Zstring '];'];
%Evaluate strings with array assignments.
eval([Astring ' ' Xstring ' ' Zstring])
%Done creating the variables A, X, and Z ----------------------------
%Solve matrrix equation - this is the meat of the algorithm.
V=simplify(inv(A)*Z);
%Evaluate each of the unknowns in the matrix X.
for i=1:length(V),
eval([char(X(i)) '=' char(V(i)) ';']);
end
%Assign a numeric value to each passive element, if one is provided.
for i=1:numElem
if ~isnan(Element(i).Value),
eval([Element(i).Name '=' num2str(Element(i).Value) ';']);
end end
%Assign a numeric value to each voltage source, if one is provided.
for i=1:numV
if ~isnan(Vsource(i).Value),
eval([Vsource(i).Name '=' num2str(Vsource(i).Value) ';']);
end end
%Assign a numeric value to each passive element, if one is provided.
for i=1:numI
if ~isnan(Isource(i).Value),
eval([Isource(i).Name '=' num2str(Isource(i).Value) ';']);
end end
die symbolischen Variablen werden ja auch nciht da erstellt, sondern erst später. Es wird sozusagen ein Befehl zusammengebastelt, der dann hier ausgeführt wird:
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