how to subtract the numeric data stored in two files

Hi,i have two files which consists of numeric data which is stored in 4-columns in each file, where each column represents a particular parameter.How can i subtract the 1st column of the first file with the 1st column of the 2nd file,similarly 2nd column of the first file with the 2nd column of the 2nd file and so on....and the resultant columns should be stored in the new file... I would be greatfull if somebody assists me in solving this problem Thank you in advance.

Answer 1

[Geoff Hayes]

Consider using dlmread which will allow you to read the numeric data from each (ASCII) file into separate matrices. Your code can then subtract one matrix from the other, and the result can be written to file using dlmwrite.

[RAHUL KM]

The matrices which are stored in the files are not in equal dimensions!!can you tell me how can i subtract them after reading from dlmread command?

[Geoff Hayes]

Is the dimension difference due to there being a different number of rows or a different number of columns?

[RAHUL KM]

its due to different number of rows!

[Geoff Hayes]

Since both matrices have the same number of columns, then determine which matrix has more rows (use size) and then just subtract a subset of those rows from the other matrix. For example,

 A = [1 2 3; 4 5 6];
 B = [2 4 6; 4 5 6; 7 8 9];
 C = A - B(1:2,:);

In the above, B has more rows than A, so when we do the subtraction, we just consider the first two rows of B via 1:2 and all columns of B via :.

[RAHUL KM]

ya but the matrices will generate dynamically in two files with in a for loop!can u guide me how can i code it for any general case?

[Geoff Hayes]

Type doc size to see how this function can help. Try to do it, and if it doesn't work the way you expect, post your code and I will try to guide you.

[RAHUL KM]

Basically i am trying to compare a given transformed audio input with the original audio present in the database and to determine how much similar it will be with the original audio.for this i will calculate the spectral features(centroid,energy,roll_off,flux) of the two audios and will store them in the file called spectral1.doc(i/p) and file1,file2,file3.....so on(for original audios) and then i will calculate the eucledian distance b/w the i/p file matrix and all the files generated for my original audios and the minimum distance will give me the most similar audio for the given input..is my approach for solving my problem rite? and i am stuck in b/w for achieving it!!!

[RAHUL KM]

THIS IS MY CODE!!!

filelist = dir('*.wav');

result = zeros(size(filelist));

for index = 1 : length(filelist) fprintf('Processing %s\n', filelist(index).name); result = zeros(size(filelist)); for index = 1 : length(filelist) fprintf('Processing %s\n', filelist(index).name); [y, fs] = wavread(filelist(index).name);

[signal] =y; fs=44100; windowLength=512; frameRate = 100; step=441; signal = signal / max(abs(signal)); curPos = 1; L = length(signal); numOfFrames = floor((L-windowLength)/step) + 1; c=0.8; % threshold cen_present=1; energy_present=1; roll_Pos=1; fluxpos=1; H = hamming(windowLength); m = ((fs/(2*windowLength))*[1:windowLength])'; Centroid = zeros(1,numOfFrames); Energy=zeros(1,numOfFrames); Rolloff=zeros(1,numOfFrames); Flux=zeros(1,numOfFrames); for i=1:numOfFrames cen_window = H.*(signal(cen_present:cen_present+windowLength-1)); FFT = (abs(fft(cen_window,2*windowLength))); FFT = FFT(1:windowLength); FFT = FFT / max(FFT); Centroid(i) = sum(m.*FFT)/sum(FFT); if (sum(cen_window.^2)<0.010) Centroid(i) = 0.0; end cen_present = cen_present + step;

    % short time energy of signal is calculated
    energy_window = (signal(energy_present:energy_present+windowLength-1));
    Energy(i) = (1/(windowLength)) * sum(abs(energy_window.^2));

     energy_present = energy_present + step;

     % spectral roll off calculation
   roll_window = (signal(roll_Pos:roll_Pos+windowLength-1));    
    FFT1 = (abs(fft(roll_window,512)));
    FFT1 = FFT1(1:255);
    totalEnergy = sum(FFT1);
    curEnergy = 0.0;
    countFFT1 = 1;
    while ((curEnergy<=c*totalEnergy) && (countFFT1<=255))
        curEnergy = curEnergy + FFT(countFFT1);
        countFFT1 = countFFT1 + 1;
    end
    Rolloff(i) = ((countFFT1-1))/(fs/2);
    roll_Pos = roll_Pos + step;

    % procedure to calculate Spectral flux begins here
    flux_window = H.*(signal(fluxpos:fluxpos+windowLength-1));    
    FFT2 = (abs(fft(flux_window,2*windowLength)));
    FFT2 = FFT2(1:windowLength);        
    FFT2 = FFT2 / max(FFT2);
    if (i>1)
        Flux(i) = sum((FFT2-FFTprev).^2);
    else
        Flux(i) = 0;
    end
    if (isnan(Flux(i)))
        Flux(i)=0;
    end 
     fluxpos = fluxpos + step;
     FFTprev = FFT2;

end Centroid = Centroid / (fs/2); nam=sprintf('file%d',index); fid=fopen(nam,'w'); [r col]=size(Centroid); for ii=1:1:col %fprintf(fid,'\n%f',Centroid(ii)); fprintf(fid,'\n%f\t%f\t%f\t%f',Centroid(ii),Energy(ii),Rolloff(ii),Flux(ii)); end fclose(fid);

[RAHUL KM]

sorry for the bad alignment of my code...i tried to align it properly but it is getting uploaded in this way!!!

[Geoff Hayes]

Rahul - the above code and request to review it falls outside the scope of the original question, and will be confusing for future readers of this question. Please create a new post outlining the problem you are experiencing with your code and the help that you are looking for.

As for formatting, highlight the code and press the {}Code button.

[RAHUL KM]

ya! i selected my code and pressed {}code button but still i am not getting it!