MATLAB - Parsing NASA thermodynamic data

AIM

To parse the NASA's THERMO.dat file to calculate required datas

CODE EXPLANATION

To find no of lines and no of species, seperate code is done

%parsing file
clc
clear all
close all
f1=fopen('THERMO.dat','r')
c=0;
noline=0;
ct=0;
while (c==0)
  line=fgetl(f1);
  if (line(length(line))=='1')
    ct=ct+1;
  end
  noline=noline+1;
  if (strcmp(line,'END'))
    c=1;
  end
end
sprintf(' No. of lines=%f \n No. of species=%f',noline,ct)

Main program:

1. clc, clear all, close all to clear screen, clear workspace, close figures.
2. Open thermo.dat in reading mode using fopen
3. First 2 lines saved as line1 and line2 respectively. Form line 2 global temperatures extracted.
4. Next 3 lines are ignored by fgetl as they are comments
5. Started for loop for 53 nos(no of species)
6. Inside it the next line was saved as species using fgetl.
7. From species, name and local temperatures were extracted
8. Then called function calc_cp_h_s providing no. of inputs (including pointer for file opening) to return specific heat, enthalphy, entrophy
9. From the values, 3 required plots were plotted, which subsequently saved in a folder seperately which was created in function
10. Changed directory to current location
11. name changed to upper case
12. Atomic weights for elements array created
13. Then to find molecular mass, 2 for loops used, one for counting name array, another for elements which was compared inside it
14. If same, then current molecular mass value added with respective molecular weight of elements
15. Another if loop created to add atomic weight of previous element if no presents
16. Displayed the values using sprintf command.
17. Closed file using fclose command.

close all
clear all
clc

%Opening and reading 
f1=fopen('THERMO.dat','r')          
%Heading line
line1=fgetl(f1);
%Global temperatures                        
line2=fgetl(f1) ;                        
%Ignoring comments
fgetl(f1);                    
fgetl(f1);                    
fgetl(f1);                     
%Extracting global low,mid,high temperatures individually
G=strsplit(line2,' ');
GLT=str2num(G{2});
GMT=str2num(G{3});
GHT=str2num(G{4});

%loop for storing each species information in seperate folders 
for i=1:53
  %Universal gas constant
  R =8.314;
  %first line saved as species    
  species=fgetl(f1);      
  %since max length of species name is 6, 1:6 used    
  name=species(1:6);
  %Extracting local low, high, mid temperatures respectively
  lt=strfind(species,'.');
    llt=str2num(species((lt(1)-4):(lt(1)+3)));
    lht=str2num(species((lt(1)+4):(lt(2)+3)));
    lmt=str2num(species((lt(2)+4):(lt(3)+3)));
  [Cp,H,S]=calc_cp_h_s(f1,llt,lht,lmt,name);
  temp=linspace(llt,lht,100);
  %plotting
  %Temperature vs Specific heat
  figure(1)
  plot(temp,Cp,'linewidth',3,'color','r')
  title(name)
  xlabel('Temperature')
  ylabel('Specific heat')
  %Temperature vs Enthalpy
  figure(2)
  plot(temp,H,'linewidth',3,'color','b')
  title(name)
  xlabel('Temperature')
  ylabel('Enthalpy')
  %Temperature vs Entropy
  figure(3)
  plot(temp,S,'linewidth',3,'color','g')
  title(name)
  xlabel('Temperature')
  ylabel('Entropy')
  
  %changing directory
  dir=(['F:\Octave files\parse file challenge\',name]);   
  cd(dir)
  %saving the plots
  saveas(1,'Specific heat.jpg');
  saveas(2,'Enthalpy.jpg');
  saveas(3,'Entropy.jpg');
  
  %changing the directory (to read thermodat file for calculation of molecular mass)
  cd('F:/Octave files')       
  
  %calculation of molecular mass
  name=upper(name); 
  elements=['H', 'C', 'N', 'O', 'A'];
  %Atomic weights of elements wrt elements array
  aw=[1.00794 12.0107 14.0067 15.9994 39.948]; 
  mm=0; 
  for i=1:length(name)
   for j=1:length(elements)
    if strcmp(name(i),elements(j))
     mm=mm+aw(j); 
     f=j;
    end
   end
   %if no. present in the name
   n=str2num(name(i));
   if n>1
    mm=mm + aw(f)*(n-1);
   end
  end
  sprintf('molecular weight of %s=%d',name,mm)
end

%closeing file
fclose(f1)​

Function code:

1. Since pointer is passed in function cursor position remains same.
2. Next 3 lines were received as seperate variables using fgetl
3. using findstr 'E' located. From which the coefficients are extracted sequentialy as shown(for ex column 1 to E+3 column for first coefficients)
4. temperature range defined from low local temperature to high local temperature of 100 divisions
5. Folder with the name of species created here.
6. Cp,H,S calculated by given formula(if temp>mid local temperature use high temperature coefficients)
7. return Cp,H,S

function [Cp,H,S]=calc_cp_h_s(f1,llt,lht,lmt,name)
  %Extracting line 1 coefficients
  line_1=fgetl(f1);  
    l1=strfind(line_1,'E');
    coef1=str2num(line_1(1:(l1(1)+3)));
    coef2=str2num(line_1((l1(1)+4):(l1(2)+3)));
    coef3=str2num(line_1((l1(2)+4):(l1(3)+3)));
    coef4=str2num(line_1((l1(3)+4):(l1(4)+3)));
    coef5=str2num(line_1((l1(4)+4):(l1(5)+3)));
  %Extracting line 2 coefficients
  line_2=fgetl(f1);
    l2=strfind(line_2,'E');
    coef6=str2num(line_2(1:(l2(1)+3)));
    coef7=str2num(line_2((l2(1)+4):(l2(2)+3)));
    coef8=str2num(line_2((l2(2)+4):(l2(3)+3)));
    coef9=str2num(line_2((l2(3)+4):(l2(4)+3)));
    coef10=str2num(line_2((l2(4)+4):(l2(5)+3)));
  %Extracting line 3 coefficients
  line_3=fgetl(f1);
    l3=strfind(line_3,'E');
    coef11=str2num(line_3(1:(l3(1)+3)));
    coef12=str2num(line_3((l3(1)+4):(l3(2)+3)));
    coef13=str2num(line_3((l3(2)+4):(l3(3)+3)));
    coef14=str2num(line_3((l3(3)+4):(l3(4)+3)));

  %creating folder for each species
  mkdir(['F:\Octave files\parse file challenge\',name]);                              

  %Universal gas constant
  R =8.314;
  
  %calculation of properties based on the lower and upper temperature
  temp=linspace(llt,lht,100);
  for j=1:length(temp)
    if j

Results:

molecular mass

Folders

Plots

O2

N2

CO2

ERRORS FACED

Few brackets missed here and there, which was added appropriately for successful execution

CONCLUSION

Successfully THERMO.dat was parsed and required datas were collected.