Read text file from function

Hi!

Im trying an old course matlab program and it read data from a text file but it isnt working and i cant figure out whats wrong. Im not familiar with reading in files from matlab functions, hope someone can help me out? Please see attached files. Can someone see if the command below will function as it should?

fid = fopen('truss2D.inp','r');

[node,element,Dzero,Fs,elem_force,Nn,Ne] = read_input(fid);

fclose(fid);

The text files has the following text:

*NODE [Node number, X-coordinate, Y-coordinate]

1, 0.0, 0.0

2, 4.0, 3.0

3, 0.0, 3.0

*ELEMENT [Element no., Node 1, Node 2, E, A]

1, 1, 2, 200e9, 25.0e-4

2, 2, 3, 200e9, 4.0e-4

3, 1, 3, 200e9, 6.0e-4

*ZeroDiplacement [Node number, D.O.F.]

1,1

2,1

2,2

3,2

*PointForce [Node number, D.O.F., force value]

1,2, -5.0e4

*VolumeForce [Element number, q0, q1, q2]

3, -1.0e7, 0, 0

*END

% This routine reads in-put data from the file "truss2D.inp"

function [node,element,Dzero,Fs,elem_force,Nn,Ne] = read_input(fid)

data = [];

%

% Node numbers and coordinates

data = str2num(fopen(fid));

data = str2num(fopen(fid));

while (length(data) > 0)

Nnum = round(data(1));

node(Nnum,1:2) = data(2:3);

data = str2num(fopen(fid));

end

Nn = length(node(:,1));

%

% Elements (connectivity, E & A)

data = str2num(fopen(fid));

while (length(data) > 0)

Enum = round(data(1));

element( Enum, 1:4) = data(2:5);

data = str2num(fopen(fid));

end

Ne = length(element(:,1));

%

% Zero displacement Boundary Conditions

Dzero = zeros(2*Nn,1);

data = str2num(fopen(fid));

while (length(data) > 0)

if (data(2) == 1)

Dzero(2*data(1)-1) = 1;

elseif (data(2) == 2)

Dzero(2*data(1)) = 1;

end

data = str2num(fopen(fid));

end

%

% Applied point forces

Fs = zeros(2*Nn,1);

data = str2num(fopen(fid));

while (length(data) > 0)

if (data(2) == 1)

Fs(2*data(1)-1) = data(3);

elseif (data(2) == 2)

Fs(2*data(1)) = data(3);

end

data = str2num(fopen(fid));

end

%

% Applied volume forces

elem_force = zeros(Ne,4);

data = str2num(fopen(fid));

while (length(data) > 0)

elem_force(data(1),:) = data;

data = str2num(fopen(fid));

end

return

%*************************************************************

[Mario Malic]

We can't help if you don't provide us with the read_input function.

Here's an example how to read the file, you'll need to process it further to get the required outputs.

function fileData = ReadFile(inputFilePath)
% Function reads supplied filepath and outputs it as the cell fileData
fileData = splitlines(fileread(inputFilePath));
end

[Daniel Arvidsson]

Youre right Mario, i forgot. Its been provided now, thanks!

Answer 1

[Mario Malic]

Hi again,

here's a script that processes the input files. There are two parameters missing n, Ne. Implement these and convert this script to function.

Note: it uses ReadFile function.

clc;
clear;
format long g % Element contains 1E11 number, other elements are not displayed nicely without this

fileData = ReadFile('truss2D_inp.txt');

keywordGroup = contains(fileData, '*'); % Returns logical array where character '*' is found
keywordStrings = {'Node', 'Element', 'ZeroDisplacement', ...
    'PointForce', 'VolumeForce'}; 
emptyVals = cell(size(keywordStrings)); 
structPairs = reshape([keywordStrings;emptyVals], 1, []); % Reshape into name-value pair for struct
inputData = struct(structPairs{:});

% Looping over fileData
jj = 0;
for ii = 1 : length(fileData)
    if keywordGroup (ii) % if '*' is found, increment the keywordStrings index
        jj = jj + 1;
    else
        inputData(ii).(keywordStrings{jj}) = str2num(fileData{ii});
    end
end

% Processed data
Node = vertcat(inputData.(keywordStrings{1}));
finElement = vertcat(inputData.(keywordStrings{2}));
fixedDisp = vertcat(inputData.(keywordStrings{3}));
pForce = vertcat(inputData.(keywordStrings{4})); 
volumeForce = vertcat(inputData.(keywordStrings{5})); 
% missing N and NE

function fileData = ReadFile(inputFilePath)
% Function reads supplied filepath and outputs it as the cell fileData
fileData = splitlines(fileread(inputFilePath));
end

[Rik]

An alternative for this ReadFile function is my readfile function, which should be a bit more robust that what you can achieve with a oneliner.