16-May-2021 15:26:22 wtime_test(): MATLAB/Octave version 4.2.2. Test wtime(). wtime_test01(): Time the RAND function: x = rand ( n, 1 ); Data vectors will be of minimum size 1024 Data vectors will be of maximum size 1048576 Number of repetitions of the operation: 5 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 1024 0.000402 0.000473 0.000191 0.000201 0.000191 2048 0.000221 0.000201 0.000231 0.000201 0.000201 4096 0.000272 0.000211 0.000211 0.000221 0.000262 8192 0.000282 0.000292 0.000262 0.000251 0.000262 16384 0.000362 0.000332 0.000322 0.000322 0.000322 32768 0.000543 0.000533 0.000453 0.000463 0.000453 65536 0.000915 0.000885 0.000724 0.000734 0.000785 131072 0.001609 0.001569 0.001318 0.001277 0.001277 262144 0.003168 0.003128 0.002374 0.002434 0.002474 524288 0.005924 0.005804 0.004647 0.004647 0.004607 1048576 0.011708 0.011748 0.009073 0.009073 0.009063 wtime_test02() Time vectorized operations: y(1:n) = x(1:n) y(1:n) = PI * x(1:n) ) y(1:n) = sqrt ( x(1:n) ) y(1:n) = exp ( x(1:n) ) Data vectors will be of minimum size 4096 Data vectors will be of maximum size 4194304 Number of repetitions of the operation: 5 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000201 0.000201 0.000241 0.000191 0.000191 8192 0.000201 0.000191 0.000191 0.000201 0.000191 16384 0.000201 0.000201 0.000191 0.000191 0.000191 32768 0.000221 0.000201 0.000251 0.000201 0.000201 65536 0.000221 0.000221 0.000282 0.000221 0.000221 131072 0.000272 0.000241 0.000302 0.000262 0.000262 262144 0.000352 0.000332 0.000382 0.000372 0.000362 524288 0.000543 0.000614 0.000583 0.000563 0.000553 1048576 0.003219 0.000724 0.000935 0.000925 0.000885 2097152 0.008047 0.001509 0.001529 0.001509 0.001499 4194304 0.014806 0.001408 0.001318 0.001509 0.001308 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000211 0.000211 0.000272 0.000221 0.000221 8192 0.000201 0.000211 0.000211 0.000221 0.000221 16384 0.000251 0.000251 0.000251 0.000251 0.000241 32768 0.000272 0.000302 0.000302 0.000302 0.000302 65536 0.000322 0.000422 0.000412 0.000473 0.000453 131072 0.000372 0.000674 0.000674 0.000674 0.000644 262144 0.000573 0.001137 0.001137 0.001147 0.001217 524288 0.001127 0.002334 0.002243 0.002263 0.002293 1048576 0.001861 0.004043 0.003903 0.004194 0.004064 2097152 0.007785 0.007886 0.007936 0.007866 0.007856 4194304 0.014303 0.014534 0.015057 0.014504 0.014504 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000282 0.000231 0.000392 0.000241 0.000241 8192 0.000251 0.000262 0.000262 0.000262 0.000272 16384 0.000322 0.000322 0.000322 0.000322 0.000322 32768 0.000453 0.000493 0.000453 0.000493 0.000453 65536 0.000714 0.000714 0.000714 0.000734 0.000704 131072 0.001267 0.001237 0.001358 0.001247 0.001237 262144 0.002323 0.002404 0.002615 0.002414 0.002323 524288 0.004637 0.004627 0.004848 0.004587 0.004546 1048576 0.008831 0.008721 0.009012 0.008751 0.008690 2097152 0.017813 0.017421 0.017562 0.017522 0.017351 4194304 0.034017 0.034088 0.033967 0.034037 0.033444 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000322 0.000332 0.000262 0.000272 0.000262 8192 0.000312 0.000312 0.000312 0.000312 0.000312 16384 0.000433 0.000443 0.000433 0.000473 0.000433 32768 0.000704 0.000684 0.000674 0.000674 0.000684 65536 0.001177 0.001227 0.001167 0.001167 0.001167 131072 0.002203 0.002193 0.002203 0.002152 0.002203 262144 0.004154 0.004144 0.004164 0.004154 0.004204 524288 0.008187 0.008198 0.008107 0.008198 0.008268 1048576 0.015862 0.015993 0.015771 0.016003 0.015872 2097152 0.032096 0.031784 0.031704 0.032136 0.031704 4194304 0.062311 0.062381 0.062221 0.061838 0.062221 wtime_test03 Time unvectorized operations: for i = 1 : n y(i) = x(i) y(i) = PI * x(i) ) y(i) = sqrt ( x(i) ) y(i) = exp ( x(i) ) end Data vectors will be of minimum size 4096 Data vectors will be of maximum size 4194304 Number of repetitions of the operation: 5 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.014745 0.016164 0.019282 0.017079 0.015590 8192 0.029048 0.031824 0.038443 0.029471 0.029783 16384 0.058740 0.064192 0.079471 0.060209 0.059565 32768 0.116354 0.131230 0.156336 0.118798 0.120267 65536 0.234157 0.254404 0.323112 0.238130 0.238170 131072 0.465688 0.475827 0.583018 0.494697 0.521884 262144 0.929285 0.984153 1.115373 1.044171 1.039001 524288 1.881010 2.182678 2.180837 2.656725 2.050854 1048576 3.725468 4.047675 4.831466 4.594171 3.900784 2097152 7.494508 7.968846 8.460747 8.111443 7.910176 4194304 14.884299 16.730748 16.734178 15.709832 15.542131 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.022078 0.021585 0.022470 0.022068 0.025890 8192 0.048974 0.042989 0.046751 0.046912 0.052162 16384 0.089851 0.085516 0.090484 0.099939 0.105511 32768 0.187627 0.171574 0.183694 0.201085 0.202001 65536 0.387717 0.341388 0.372861 0.387425 0.458004 131072 0.792573 0.688590 0.743257 0.742231 0.870213 262144 1.648020 1.517272 1.514275 1.477592 1.645686 524288 3.255022 2.899864 3.039633 2.814298 3.285217 1048576 6.751794 6.410064 5.981480 5.731381 6.301424 2097152 12.441584 11.877827 11.694324 12.536202 11.372690 4194304 23.094986 23.727089 24.453629 26.293672 23.227062 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.024643 0.025940 0.024653 0.024804 0.025719 8192 0.049919 0.049919 0.050442 0.048773 0.050905 16384 0.100181 0.101046 0.099949 0.099698 0.101579 32768 0.201990 0.200462 0.198711 0.196670 0.204475 65536 0.405721 0.391700 0.404745 0.414914 0.407371 131072 0.824739 0.802953 0.896002 0.852460 0.838760 262144 1.693745 1.624805 1.657655 1.631605 1.731443 524288 3.498291 3.261429 3.430669 3.280570 3.289994 1048576 6.800013 6.728016 6.658584 6.737038 6.592642 2097152 13.600429 13.494616 13.197102 13.261495 13.432466 4194304 26.626571 26.788076 26.545803 26.729718 26.530685 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.026131 0.027469 0.024864 0.027952 0.024794 8192 0.052786 0.055331 0.049396 0.058851 0.049215 16384 0.103339 0.114373 0.111677 0.104154 0.102947 32768 0.221795 0.218838 0.224682 0.200693 0.195966 65536 0.441689 0.447996 0.407843 0.415588 0.405087 131072 0.871601 0.873290 0.867386 0.820605 0.809732 262144 1.603160 1.614515 1.735114 1.790767 1.695676 524288 3.324917 3.421325 3.322734 3.345053 3.407314 1048576 6.670604 6.663492 6.701784 6.771649 6.833326 2097152 13.345824 13.515356 13.823602 13.474972 13.360750 4194304 27.060344 26.621179 27.272071 27.224284 26.835883 wtime_test04() Time the 2D nearest neighbor problem. Given X(2,N) and Y(2), find X(2,*) closest to Y(2). for i = 1 : n if distance ( x(2,i), y ) < minimum so far x_min = x(2,i) end Data vectors will be of minimum size 1024 Data vectors will be of maximum size 1048576 Number of repetitions of the operation: 5 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 1024 0.011768 0.013116 0.012030 0.013508 0.012764 2048 0.023064 0.026675 0.023898 0.028093 0.026101 4096 0.047123 0.050965 0.049879 0.053621 0.051961 8192 0.097294 0.109776 0.096841 0.104948 0.104083 16384 0.189106 0.216132 0.187024 0.205219 0.204425 32768 0.379539 0.414200 0.385323 0.395341 0.403538 65536 0.835190 0.797411 0.810899 0.761110 0.781981 131072 1.570169 1.605805 1.598885 1.587831 1.525872 262144 3.254830 3.109971 3.190558 3.144873 3.038597 524288 6.412810 6.473974 6.252058 6.217961 6.111504 1048576 12.817945 12.628276 12.696813 12.870540 12.706922 wtime_test05() Time the matrix multiplication problem. Compute C = A * B where A is an L by M matrix, B is an M by N matrix, and so C is an L by N matrix. Minimum value of L = M = N = 4 Maximum value of L = M = N = 1024 Number of repetitions of the operation: 5 Use triple loop for matrix multiplication. Timing results using nested loops: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4 0.001086 0.001237 0.001006 0.001006 0.001006 16 0.048783 0.056618 0.048984 0.055059 0.048753 64 3.305474 3.253151 3.336162 3.287550 3.205987 256 208.899289 208.271260 209.820176 208.594564 206.143883 Use C = A * B matrix multiplication. Timing results using C = A * B: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4 0.001096 0.000473 0.000422 0.000443 0.000433 16 0.000211 0.000443 0.000443 0.000443 0.000422 64 0.000231 0.000483 0.000463 0.000483 0.000463 256 0.001096 0.000684 0.000674 0.000694 0.000674 wtime_test(): Normal end of execution. 16-May-2021 16:01:54