performance measurements
Each table row shows performance measurements for this C gcc program with a particular command-line input value N.
| N | CPU secs | Elapsed secs | Memory KB | Code B | ≈ CPU Load |
|---|---|---|---|---|---|
| 500 | 0.17 | 0.17 | ? | 383 | 0% 0% 6% 94% |
| 3,000 | 6.16 | 6.17 | 468 | 383 | 1% 0% 100% 0% |
| 5,500 | 20.70 | 20.71 | 464 | 383 | 0% 0% 0% 100% |
Read the ↓ make, command line, and program output logs to see how this program was run.
Read spectral-norm benchmark to see what this program should do.
notes
gcc (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
spectral-norm C gcc program source code
/* The Computer Language Benchmarks Game * http://benchmarksgame.alioth.debian.org/ * * Contributed by Sebastien Loisel */ #include <stdio.h> #include <stdlib.h> #include <math.h> double eval_A(int i, int j) { return 1.0/((i+j)*(i+j+1)/2+i+1); } void eval_A_times_u(int N, const double u[], double Au[]) { int i,j; for(i=0;i<N;i++) { Au[i]=0; for(j=0;j<N;j++) Au[i]+=eval_A(i,j)*u[j]; } } void eval_At_times_u(int N, const double u[], double Au[]) { int i,j; for(i=0;i<N;i++) { Au[i]=0; for(j=0;j<N;j++) Au[i]+=eval_A(j,i)*u[j]; } } void eval_AtA_times_u(int N, const double u[], double AtAu[]) { double v[N]; eval_A_times_u(N,u,v); eval_At_times_u(N,v,AtAu); } int main(int argc, char *argv[]) { int i; const int N = ((argc == 2) ? atoi(argv[1]) : 2000); double u[N],v[N],vBv,vv; for(i=0;i<N;i++) u[i]=1; for(i=0;i<10;i++) { eval_AtA_times_u(N,u,v); eval_AtA_times_u(N,v,u); } vBv=vv=0; for(i=0;i<N;i++) { vBv+=u[i]*v[i]; vv+=v[i]*v[i]; } printf("%0.9f\n",sqrt(vBv/vv)); return 0; }
make, command-line, and program output logs
Sat, 27 Apr 2013 05:10:30 GMT MAKE: /usr/bin/gcc -pipe -Wall -O3 -fomit-frame-pointer -march=native -fopenmp -mfpmath=sse -msse2 spectralnorm.c -o spectralnorm.gcc_run -lm rm spectralnorm.c 0.18s to complete and log all make actions COMMAND LINE: ./spectralnorm.gcc_run 5500 PROGRAM OUTPUT: 1.274224153