Below is one approach to reading FORTRAN (formatted) files. Basically, the file is read with a textread command, and converted into a character array. Key header lines (that indicate the start of data) are located with the strmatch command. The data can be check to see if stars were written out (fortran overflow) with the findstr command. And the numbers are read with the str2num command. If you need/want further guidance on your specific example, let me know. The example below is somewhat complex, since the data may have overflow (stars) and the number of eigenvalues to be read changes for each case. But you should be able to follow it.
In step by step directions
1) Open the file with textread, and convert to a character array (using char command). Store in a character array named file.
example code: Open a file named 'fortran.dat'
fname = 'fortran.dat'
file = char(textread(deblank(fname),
'%s','delimiter','\n','whitespace',''));
2) Find key lines using strmatch command. A key line is a line with some type of a header, and the data that you want to read is a fixed number of lines from that header.
example code: Find all occurances of the header line "1EIGENVALUES"
eigen_row=strmatch('1EIGENVALUES',file);
3) Determine how many header lines were found via size command.
example code: Determine the number of 1EIGENVALUE headers
ni = size(eigen_row,1);
4) Loop through the header lines with for statement
example code: Loop through header lines
for ii=1:ni
5) Numbers can be read with the str2num command. You need to specifiy how many rows down from the header line, and the column range.
typical code: num = str2num(file(header_row+nlines,start_col:end_col));
example code:
% Start and end of eigenvalues
ic_start = eigen_row(ii)+12;
ic_end = ic_start+mxx(ii)-1;
ic_err = eigen_row(ii)-3;
% Copy data into temp array
eig_lines=file(ic_start:ic_end,
;
% Correct each line for length
eig_lines = my_adjust_eig(eig_lines);
% Read each of the eigenvalue table lines
nlines = size(eig_lines,1);
neig=0;
for iline=1:nlines % Loop over the lines
line=eig_lines(iline,
;
[im_lambda, err] = check_str(line(47:57));
if (im_lambda >= 0)
neig = neig+1;
freq_hz(neig,ii) = check_str(line(71:83));
end
end
6) If needed, use findstr to check for valid data. For fortran, you could check for stars (overflow write)
stars = findstr(str,'*');
if isempty(stars) ~= 0
num = str2num(str);
err = 0;
if length(num)~=1
num = nan;
err=1;
end
else
num = nan;
err=1;
end
Here is a complete program, you should be able to follow it
function read_freq
fname='freq9b.com.out';
[rpm,coll,f_cpm]=readcmrd(fname);
iline=0;
for icase=1:size(f_cpm,2);
% for ifreq=size(f_cpm,1):-1:1
for ifreq=size(f_cpm,1):-1:size(f_cpm,1)
iline=iline+1;
% s=sprintf('%6.4f %4.1f %4.0f', f_cpm(ifreq,icase)/rpm(icase), rpm(icase), coll(icase));
s=sprintf('%5.1f %5.1f %6.4f', coll(icase), rpm(icase), f_cpm(ifreq,icase)/rpm(icase));
ns=size(s,2);
sp(iline,1:ns)=s;
end
iline=iline+1;
end
sp
function [rotor_speed_rpm,coll_deg,freq_cpm] = readcmrd(fname)
file = char(textread(deblank(fname),'%s','delimiter','\n','whitespace',''));
eigen_row=strmatch('1EIGENVALUES',file);
performance_row=strmatch('ROTORCRAFT PERFORMANCE ',file);
mxx_row = strmatch('NUMBER OF STATES, MXX =',file);
mxx=str2num(file(mxx_row,27:30));
ni = size(eigen_row,1);
for ii=1:ni
% Read the rotor speed
rotor_speed_rpm(ii) = str2num(file(performance_row(ii)+11,112:120));
coll_deg(ii) = str2num(file(performance_row(ii)+19,25:35));
% Read the eigenvalues
% Two difficulties in reading eigenvalues
% 1) The initial spaces are skipped, so the location of the number
% depends on how much white space is on that line
% 2) Data with stars in freq, damp, real/sec or imag/sec has to be removed
% 3) Remove data with negative imaginary part
% 4) Print information if an error occurs
% Start and end of eigenvalues
ic_start = eigen_row(ii)+12;
ic_end = ic_start+mxx(ii)-1;
ic_err = eigen_row(ii)-3;
if (strcmp(file(ic_err,1:9),'*** ERROR') == 0)
% Copy data into temp array
eig_lines=file(ic_start:ic_end,
;
% Correct each line for length
eig_lines = my_adjust_eig(eig_lines);
% Read each of the eigenvalue table lines
nlines = size(eig_lines,1);
neig=0;
for iline=1:nlines % Loop over the lines
line=eig_lines(iline,
;
[im_lambda, err] = check_str(line(47:57));
if (im_lambda >= 0)
neig = neig+1;
freq_hz(neig,ii) = check_str(line(71:83));
end
end
else
end
end
freq_cpm = freq_hz*60;
function lines2 = my_adjust_eig(lines1)
% The last character in each line is in column 127
nlines = size(lines1,1);
for iline=1:nlines
sp = findstr(lines1(iline,
,' ');
lastchr = size(lines1,2);
csp = size(sp,2);
while (lastchr == sp(csp))
lastchr = lastchr-1;
csp=csp-1;
end
fchar=121;
if((lines1(iline,lastchr)== 'n') == 1)
lines2(iline,1:fchar-lastchr-12) = ' ';
lines2(iline,fchar-lastchr-12+1:fchar-12) = lines1(iline,1:lastchr);
lines2(iline,fchar-12+1:fchar) = ' ';
else
lines2(iline,1:fchar-lastchr) = ' ';
lines2(iline,fchar-lastchr+1:fchar) = lines1(iline,1:lastchr);
end
end
function [num, err] = check_str(str);
stars = findstr(str,'*');
if isempty(stars) ~= 0
num = str2num(str);
err = 0;
if length(num)~=1
num = nan;
err=1;
end
else
num = nan;
err=1;
end
