[37] | 1 | if 0
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| 2 | % run under matlab 5
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| 3 | a = rand(2,3);
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| 4 | b = rand(3,4);
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| 5 | c = rand(3);
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| 6 | flops(0); a+a; flops
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| 7 | flops(0); a.*a; flops
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| 8 | flops(0); a./a; flops
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| 9 | flops(0); a<a; flops
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| 10 | flops(0); exp(a); flops
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| 11 | flops(0); log(a); flops
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| 12 | flops(0); a*a'; flops
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| 13 | flops(0); a*b; flops
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| 14 | flops(0); a/b'; flops
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| 15 |
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| 16 | ns = 1:10;
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| 17 | f = [];
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| 18 | for n = ns
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| 19 | c = rand(n);
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| 20 | c = c*c';
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| 21 | flops(0); chol(c); f(n) = flops;
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| 22 | end
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| 23 | f = [1 5 14 30 55 91 140 204 285 385];
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| 24 | x = [ones(size(ns)); ns; ns.^2; ns.^3];
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| 25 | a = f/x
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| 26 | plot(ns,f - a*x)
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| 27 | end
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| 28 |
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| 29 | niter = 2000;
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| 30 | a = rand(100);
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| 31 | b = rand(100);
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| 32 | if 0
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| 33 | tic; for i=1:niter ones(100); end; t_ones=toc/niter;
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| 34 | fprintf('time for ones: %g\n', t_ones);
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| 35 | else
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| 36 | t_ones = 0;
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| 37 | end
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| 38 | t = [];
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| 39 | tic; for i=1:niter a+4; end; t(1)=toc/niter;
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| 40 | tic; for i=1:niter a+b; end; t(2)=toc/niter;
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| 41 | tic; for i=1:niter a.*b; end; t(3)=toc/niter;
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| 42 | t_arith = mean(t) - t_ones;
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| 43 | fprintf('average for +,*: %g\n', t_arith);
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| 44 | if 0
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| 45 | % By time, == takes 2 flops, but this is processor dependent.
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| 46 | t = [];
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| 47 | tic; for i=1:niter a>b; end; t=toc/niter;
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| 48 | fprintf('time for >: %g\tflops = %g (should be %g)\n', t, t/t_arith, 2);
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| 49 | %tic; for i=1:niter a==b; end; t=toc/niter;
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| 50 | tic; for i=1:niter a~=b; end; t=toc/niter;
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| 51 | fprintf('time for ~=: %g\tflops = %g\n', t, t/t_arith);
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| 52 | end
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| 53 | if 0
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| 54 | tic; for i=1:niter randn(100); end; t=toc/niter;
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| 55 | t = t-t_ones;
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| 56 | fprintf('time for randn: %g\tflops = %g\n', t, t/t_arith);
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| 57 | end
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| 58 | if 0
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| 59 | tic; for i=1:niter a.^(0.51); end; t=toc/niter;
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| 60 | e1 = exp(1);
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| 61 | tic; for i=1:niter e1.^a; end; t=toc/niter;
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| 62 | t = t-t_ones;
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| 63 | fprintf('time for pow: %g\tflops = %g\n', t, t/t_arith);
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| 64 | if 0
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| 65 | tic; for i=1:niter a.^(0.5); end; toc
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| 66 | tic; for i=1:niter sqrt(a); end; toc
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| 67 | end
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| 68 | end
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| 69 | tic; for i=1:niter sqrt(a); end; t_sqrt=toc/niter;
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| 70 | fprintf('time for sqrt: %g\tflops = %g (should be %g)\n', t_sqrt, t_sqrt/t_arith, flops_sqrt);
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| 71 | tic; for i=1:niter exp(a); end; t_exp=toc/niter;
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| 72 | fprintf('time for exp: %g\tflops = %g (should be %g)\n', t_exp, t_exp/t_arith, flops_exp);
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| 73 | tic; for i=1:niter pow2(a); end; t_pow2=toc/niter;
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| 74 | fprintf('time for pow2: %g\tflops = %g (should be %g)\n', t_pow2, t_pow2/t_arith, flops_exp);
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| 75 | tic; for i=1:niter log(a); end; t_log=toc/niter;
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| 76 | fprintf('time for log: %g\tflops = %g (should be %g)\n', t_log, t_log/t_arith, flops_log);
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| 77 | tic; for i=1:niter log2(a); end; t_log=toc/niter;
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| 78 | fprintf('time for log2: %g\tflops = %g (should be %g)\n', t_log, t_log/t_arith, flops_log);
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