I am relatively new on C, I am trying to run a program and I get this Error message: Segmentation fault (core dumped) I just want to print any value of the array bits but I can not, I'd appreciate any help on this error. Code: #include <stdio.h> #include <math.h> #define COL 204 #define COL_P 2 #define ROWS_P 1020 int codecheck(int (*h)[2],int x[]) { int i,j,m,f; //flags int sum = 0; int y[COL]; for (i=0;i<COL;i++) y=0; m=1; f=-1; for(i=0;i<ROWS_P;i++) { for(j=0;j<COL_P;j++) { if(h[j][0]==m) { y[m]=y[m] + x[h[j][1]-1]; f++; } } y[m]=y[m]%2; m=m+1; i=f+1; } for (i = 0; i < COL; ++i) { sum =sum+ y; } if (sum == 0) { return 1; } else { return -1; } } int codesum (int y[]) { int sum=0; for(int i=0;i<COL;i++) sum+=y; //cout<< "sum="<< sum<<endl; if(sum>0) return 0; else return 1; } void ModulationSchemeValues (int modulationScheme, int noOfSymbols, double var, float d, float rate, double snr) { switch (modulationScheme) { case 0: //cout<<"case 0"<<endl; var=1/(2*rate*snr); noOfSymbols = COL; d=1; break; case 1: //cout<<"case 1"<<endl; var=1/(4*rate*snr); noOfSymbols = COL/2; d=1/sqrt(2); break; case 2: //cout<<"case 2"<<endl; var=1/(8*rate*snr); noOfSymbols = COL/4; d=1/sqrt(10); default: var=1/(2*rate*snr); noOfSymbols = COL; d=1; break; } } void InitializeChannelLLR (double var, int modulationScheme, int noOfSymbols, int x[], float noise[], double L_ch[], float d, int (*h)[2], double LLR[]) { int j=0; // temporary flags int k=0,t; for(int i=0;i<noOfSymbols;i++) // using randnoise function introducing noise to all zero codeword { x[j]=d; noise[j]=(x[j])+0.8; L_ch[j]= 2*noise[j]/var; j++; } for(int j=0;j<ROWS_P;j++) { //cout<<"enter loop"<<endl; //cout<< "j="<<j<<endl; //<<j<<"\t"; t=h[j][1]-1; LLR[j]=L_ch[t]; } //cout<<"L_ch initialize done \n"; } void SPADecoder(double LLR[], int (*h)[2], double LLR_ret[], double L_ch[], double L_dec[], int y[], int z) { double temp; int i,j,k; for(i=0;i<ROWS_P;i++) { temp=1; for(j=0;j<ROWS_P;j++) { if(j!=i && h[j][0]==h[0]) { temp=temp * tanhf(LLR[j]/2); } } LLR_ret = log((1 + temp)/(1 - temp)); // lower and upper bounding the LLR if(LLR_ret > 40) { LLR_ret=40; } else if(LLR_ret<-40) { LLR_ret=-40; } } for(i=0;i<COL;i++) // L_dec array used to decide the value of each bit of codeword here it is initalized to LLr value received from channel { L_dec=L_ch; } for(i=1;i<COL+1;i++) // LLR values received by the variable nodes are added and stored in L_dec for decision making { for(j=0;j<ROWS_P;j++) { if(h[j][1]==i) { L_dec[i-1]=L_dec[i-1]+LLR_ret[j]; } } if(L_dec[i-1]<=0) // decision about the bit values of the received codeword is done her and stored in Y. { y[i-1]=1; } else { y[i-1]=0; } } //z = codesum(y,col); z=codecheck(h,y); // checking whether the decoded codeword is all zero or not if(z==1) // if decoded perfectly exit the deoding loop { return ; } // updating LLR values on variable nodes side for each variable and check node for(i=0;i<ROWS_P;i++) { temp=0; for(j=0;j<ROWS_P;j++) { if(j!=i && h[j][1]==h[1]) { temp=temp + LLR_ret[j]; k=h[1]; } } LLR = temp+L_ch[k-1]; } } int main() { // flags and counters int z,i,j,N,k,ber_count,looping,t,sum; float d=1; float rate=0.5; int maxTransmissions=20,decoderIterations=10,maxErrors=100,errorsAccumulated=0; int y[COL]; // iterations gives the maximum number of time the decoder is run for each value of SNR double var,snr; double temp; //temp variable float noise[COL]; double L_ch[COL],L_dec[COL]; double LLR[ROWS_P],LLR_ret[ROWS_P]; double BER[11]; float snr_db[]={0,1,2,3,4}; int snr_range=5,snr_count; int x[]={0,1,0,0,0,0,1,0,0,1,0,1,0,0,0,0,1,1,1,1,1}; int ret,row=0; double error_bits,error; // Set Field Separator here int modulationScheme = 0,noOfSymbols=204; int h[ROWS_P][COL_P]={{1,1},{1,18},{1,27},{1,82},{1,102},{1,103},{1,130},{1,177},{1,190},{1,203},{2,2},{2,15},{2,75},{2,80},{2,86},{2,104},{2,121},{2,141},{2,144},{2,191},{3,3},{3,31},{3,32},{3,42},{3,101},{3,105},{3,153},{3,159},{3,178},{3,199},{4,4},{4,37},{4,71},{4,75},{4,85},{4,106},{4,111},{4,114},{4,127},{4,164},{5,5},{5,17},{5,42},{5,72},{5,87},{5,107},{5,141},{5,158},{5,193},{5,197},{6,4},{6,6},{6,17},{6,78},{6,102},{6,108},{6,162},{6,165},{6,167},{6,174},{7,7},{7,23},{7,73},{7,80},{7,83},{7,109},{7,118},{7,168},{7,177},{7,178},{8,8},{8,33},{8,37},{8,73},{8,100},{8,110},{8,156},{8,173},{8,192},{8,197},{9,9},{9,40},{9,41},{9,88},{9,92},{9,103},{9,111},{9,173},{9,181},{9,199},{10,10},{10,14},{10,23},{10,53},{10,93},{10,107},{10,112},{10,137},{10,167},{10,175},{11,11},{11,19},{11,26},{11,28},{11,88},{11,110},{11,113},{11,116},{11,170},{11,191},{12,1},{12,12},{12,25},{12,86},{12,97},{12,108},{12,114},{12,124},{12,161},{12,192},{13,4},{13,13},{13,33},{13,34},{13,50},{13,115},{13,137},{13,140},{13,146},{13,160},{14,14},{14,31},{14,40},{14,58},{14,95},{14,116},{14,121},{14,166},{14,174},{14,203},{15,15},{15,68},{15,70},{15,87},{15,101},{15,109},{15,113},{15,117},{15,165},{15,180},{16,4},{16,16},{16,59},{16,67},{16,92},{16,118},{16,125},{16,131},{16,138},{16,151},{17,15},{17,17},{17,44},{17,71},{17,73},{17,119},{17,161},{17,190},{17,194},{17,198},{18,18},{18,47},{18,62},{18,85},{18,93},{18,120},{18,122},{18,125},{18,146},{18,181},{19,19},{19,22},{19,23},{19,37},{19,57},{19,121},{19,126},{19,130},{19,131},{19,143},{20,1},{20,20},{20,50},{20,51},{20,99},{20,106},{20,122},{20,169},{20,179},{20,200},{21,21},{21,32},{21,62},{21,72},{21,98},{21,123},{21,126},{21,154},{21,168},{21,204},{22,22},{22,31},{22,44},{22,89},{22,98},{22,124},{22,141},{22,160},{22,169},{22,176},{23,23},{23,32},{23,61},{23,65},{23,99},{23,125},{23,132},{23,133},{23,147},{23,152},{24,16},{24,24},{24,42},{24,73},{24,77},{24,126},{24,142},{24,145},{24,146},{24,147},{25,5},{25,24},{25,25},{25,55},{25,67},{25,127},{25,133},{25,165},{25,178},{25,185},{26,10},{26,26},{26,27},{26,40},{26,85},{26,128},{26,147},{26,155},{26,160},{26,200},{27,22},{27,27},{27,42},{27,50},{27,74},{27,108},{27,129},{27,154},{27,170},{27,195},{28,2},{28,28},{28,63},{28,67},{28,94},{28,130},{28,150},{28,171},{28,187},{28,192},{29,29},{29,48},{29,69},{29,79},{29,90},{29,116},{29,131},{29,159},{29,176},{29,200},{30,7},{30,30},{30,53},{30,58},{30,94},{30,127},{30,132},{30,140},{30,162},{30,189},{31,29},{31,31},{31,64},{31,77},{31,94},{31,117},{31,133},{31,167},{31,183},{31,190},{32,20},{32,30},{32,32},{32,74},{32,78},{32,115},{32,134},{32,151},{32,181},{32,194},{33,11},{33,33},{33,47},{33,76},{33,81},{33,109},{33,135},{33,154},{33,155},{33,179},{34,2},{34,7},{34,34},{34,71},{34,76},{34,136},{34,138},{34,159},{34,182},{34,183},{35,27},{35,29},{35,35},{35,60},{35,86},{35,123},{35,137},{35,149},{35,166},{35,189},{36,17},{36,35},{36,36},{36,48},{36,100},{36,138},{36,139},{36,146},{36,163},{36,168},{37,5},{37,34},{37,37},{37,38},{37,69},{37,117},{37,139},{37,145},{37,169},{37,203},{38,38},{38,56},{38,76},{38,92},{38,101},{38,106},{38,123},{38,140},{38,161},{38,170},{39,39},{39,41},{39,60},{39,76},{39,78},{39,125},{39,141},{39,142},{39,175},{39,198},{40,2},{40,35},{40,40},{40,43},{40,93},{40,114},{40,135},{40,142},{40,148},{40,158},{41,1},{41,2},{41,13},{41,41},{41,59},{41,109},{41,119},{41,132},{41,143},{41,157},{42,11},{42,42},{42,43},{42,92},{42,95},{42,115},{42,117},{42,144},{42,156},{42,204},{43,7},{43,9},{43,43},{43,45},{43,56},{43,122},{43,145},{43,192},{43,194},{43,201},{44,10},{44,44},{44,75},{44,83},{44,95},{44,110},{44,135},{44,146},{44,157},{44,180},{45,45},{45,63},{45,79},{45,81},{45,97},{45,127},{45,139},{45,147},{45,148},{45,195},{46,34},{46,46},{46,61},{46,66},{46,77},{46,105},{46,144},{46,148},{46,197},{46,201},{47,14},{47,20},{47,46},{47,47},{47,83},{47,124},{47,128},{47,132},{47,149},{47,159},{48,8},{48,13},{48,26},{48,48},{48,62},{48,149},{48,150},{48,174},{48,193},{48,195},{49,15},{49,21},{49,25},{49,49},{49,51},{49,145},{49,149},{49,151},{49,177},{49,188},{50,8},{50,49},{50,50},{50,54},{50,89},{50,105},{50,126},{50,152},{50,164},{50,165},{51,43},{51,51},{51,66},{51,68},{51,91},{51,131},{51,133},{51,153},{51,187},{51,189},{52,1},{52,39},{52,45},{52,52},{52,54},{52,110},{52,140},{52,150},{52,154},{52,163},{53,8},{53,53},{53,60},{53,64},{53,90},{53,138},{53,155},{53,157},{53,194},{53,204},{54,12},{54,28},{54,54},{54,60},{54,82},{54,112},{54,139},{54,151},{54,156},{54,183},{55,3},{55,17},{55,37},{55,55},{55,99},{55,112},{55,148},{55,157},{55,172},{55,189},{56,20},{56,31},{56,56},{56,80},{56,91},{56,152},{56,156},{56,158},{56,162},{56,180},{57,28},{57,57},{57,66},{57,81},{57,89},{57,134},{57,137},{57,159},{57,172},{57,196},{58,5},{58,58},{58,70},{58,78},{58,91},{58,118},{58,149},{58,154},{58,160},{58,201},{59,18},{59,24},{59,59},{59,88},{59,96},{59,150},{59,152},{59,161},{59,179},{59,183},{60,21},{60,38},{60,55},{60,59},{60,60},{60,162},{60,176},{60,187},{60,190},{60,1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for(snr_count=0;snr_count<snr_range;snr_count++) { // cout<<"Decoder run for SNR in db=" <<snr_db[snr_count]<<endl; snr=pow(10,(snr_db[snr_count]/10)); ModulationSchemeValues (modulationScheme, noOfSymbols, var, d, rate, snr); // determining various values based on mdulation scheme // calulating noise variance from SNR BER[snr_count]=0; // initializing BER // normal_distribution<double> dist(0.0, 1); N=0; errorsAccumulated=0; while(errorsAccumulated<=maxErrors && N<=maxTransmissions) { N++; InitializeChannelLLR( var, modulationScheme, noOfSymbols, x, noise, L_ch, d, h, LLR); for(looping=0;looping<decoderIterations;looping++) { SPADecoder(LLR, h, LLR_ret, L_ch, L_dec, y, z); printf("%d\t", y[looping]); } if(z==1) // if decoded correctly BER for that codeword is zero { BER[snr_count]=BER[snr_count]+0; } else // if not decoded properly calulating the BER { error_bits=0; for(i=0;i<COL;i++) { if(y!=0) { error_bits++; } } errorsAccumulated+=error_bits; error=error_bits/(double)COL; BER[snr_count]=BER[snr_count]+error; } if(N%300==0) printf("iteration=%d \t errors accumulated=%d \n",N,errorsAccumulated); } BER[snr_count]=BER[snr_count]/(double)N; // averaging BER over all decoding iterations. printf("snr=%lf\tBER[%d]=%lf \n",snr_db[snr_count],snr_count,BER[snr_count]); } return 0; }
