CODEWITHSUNDEEP
matlabprintf
aditya
aditya

Reputation: 11

Syntax of 'fprintf' command in MATLAB

I've written MATLAB code for a one dimensional advection-dispersion for a conservative contaminant as follows.

% Analysis of 1D conservative contaminant migration through porous media.
% For t=25 days.

% Parameters:
dt = 1;
dx = 10;

% Coeffecients
m = (dt/dx^2)- (dt/dx);
n = -2*dt/(dx^2);
p = dt/(dx^2)+ dt/dx;

%Initialization
for i = 1:11
    c(i)= 0.0;
    h(i)= 0.0;
end

%Initial condition
c(6)= 500.0;

%Boundary condition
for i=1:11
    c(1)=0.0;
    c(11)= 0.0;
    h(1)= 0.0;
    h(11)= 0.0;
end
for k=1:25
    for i=2:10
        h(i)= c(i+1)*m + c(i)*n +c(i-1)*p;
    end
    for i=1:11
        c(i)=h(i);
    end
end

% Writing the results to file newfile.txt
fid= fopen('newfile.txt', 'wt');
fprintf(fid,%3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f
%3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f\n,h);
fclose (fid);
contour(c);

But I am stuck at the fprintf command syntax. Upon executing it, it shows that some parenthesis is missing.

Upvotes: 0

Views: 1156

Answers (3)

Cris Luengo
Cris Luengo

Reputation: 60504

You've already gotten an answer explaining why you get an error. I would however write this as:

fprintf(fid,'%3.3f ',h);
fprintf(fid,'\n');

The template is re-used until all elements in h are exhausted. The newline needs to be printed separately in this case.

Upvotes: 0

Jonas
Jonas

Reputation: 74940

You need to write the format string as string, i.e.

fprintf(fid,%3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f
%3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f\n,h);

Should be

fprintf(fid,['%3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f',...
'%3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f %3.3f\n'],h);

The dots signify a line break, and the square brackets catenate the strings on the two lines.

Also, you're not really writing Matlab code here. For example, zour initialization

for i = 1:11
    c(i)= 0.0;
    h(i)= 0.0;
end

can be written as

c = zeros(1,11);
h = zeros(1,11);
or
[c,h] = deal(zeros(1,11));

Furthermore,

for i=1:11
    c(1)=0.0;
    c(11)= 0.0;
    h(1)= 0.0;
    h(11)= 0.0;
end

Does absolutely nothing here, since you have initialized the vectors to zeros already, and even if you wanted to keep the lines in order to be able to change values, you can eliminate the loop.

Finally,

for i=1:11
   c(i)=h(i);
end

can be rewritten as c = h;

Upvotes: 3

paxdiablo
paxdiablo

Reputation: 881423

You need quotes around your format string, like so:

fprintf(fid,'%3.3f %3.3f ... %3.3f\n',h);

(don't actually put the ... in, I've just put it there as a placeholder so I don't have to type in the lot, and to improve readability).

Upvotes: 0

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