Home License -- for personal use only. Not for government, academic, research, commercial, or other organizational use. 08-Oct-2025 02:28:40 wtime_test(): MATLAB/Octave version 9.11.0.2358333 (R2021b) Update 7. 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 0.002283 0.000412 0.000020 0.000020 0.000020 2048 0.001790 0.000191 0.000010 0.000020 0.000020 4096 0.000282 0.000040 0.000030 0.000060 0.000030 8192 0.000111 0.000060 0.000060 0.000060 0.000050 16384 0.000342 0.000111 0.000111 0.000151 0.000111 32768 0.000302 0.000251 0.000201 0.000272 0.000211 65536 0.000573 0.000402 0.000402 0.000603 0.000433 131072 0.001127 0.000855 0.000805 0.000986 0.000815 262144 0.002243 0.002183 0.001599 0.001670 0.001670 524288 0.004587 0.004385 0.003249 0.003420 0.003450 1048576 0.009304 0.008650 0.006538 0.006548 0.006628 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 0.000312 0.000050 0.000030 0.000030 0.000030 8192 0.000141 0.000251 0.000020 0.000020 0.000030 16384 0.000080 0.000070 0.000070 0.000060 0.000060 32768 0.000111 0.000151 0.000111 0.000121 0.000121 65536 0.000503 0.000231 0.000231 0.000231 0.000231 131072 0.000322 0.000503 0.000463 0.000493 0.000493 262144 0.000744 0.001046 0.000996 0.001046 0.000996 524288 0.001680 0.002142 0.002102 0.002102 0.002112 1048576 0.006759 0.005411 0.004345 0.004406 0.004375 2097152 0.012744 0.007634 0.010119 0.009767 0.009867 4194304 0.028002 0.016586 0.016616 0.016536 0.017421 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000865 0.000030 0.000030 0.000030 0.000030 8192 0.000101 0.000020 0.000030 0.000030 0.000050 16384 0.000101 0.000111 0.000141 0.000111 0.000111 32768 0.000191 0.000201 0.000181 0.000171 0.000171 65536 0.000654 0.000302 0.000312 0.000342 0.000292 131072 0.000614 0.000553 0.000593 0.000573 0.000553 262144 0.001328 0.001157 0.001157 0.001157 0.001187 524288 0.002907 0.002334 0.002344 0.002303 0.002303 1048576 0.005884 0.004878 0.005100 0.004868 0.004878 2097152 0.011135 0.011145 0.011235 0.011225 0.011285 4194304 0.019060 0.019091 0.019060 0.019775 0.018960 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000302 0.000040 0.000040 0.000040 0.000040 8192 0.000111 0.000101 0.000080 0.000080 0.000080 16384 0.000201 0.000171 0.000171 0.000161 0.000151 32768 0.000262 0.000262 0.000251 0.000251 0.000251 65536 0.000805 0.000422 0.000433 0.000422 0.000422 131072 0.000855 0.000785 0.000764 0.001318 0.000835 262144 0.001629 0.001589 0.001619 0.001871 0.001579 524288 0.003188 0.003229 0.003168 0.003460 0.003199 1048576 0.006447 0.006457 0.006457 0.006397 0.006467 2097152 0.014484 0.014333 0.014605 0.014715 0.014454 4194304 0.025608 0.026262 0.025679 0.026172 0.025830 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000563 0.000101 0.000101 0.000101 0.000080 8192 0.000141 0.000050 0.000050 0.000050 0.000050 16384 0.000201 0.000151 0.000181 0.000201 0.000161 32768 0.000292 0.000262 0.000262 0.000282 0.000272 65536 0.000754 0.000463 0.000483 0.000483 0.000463 131072 0.000935 0.000885 0.000865 0.000895 0.000855 262144 0.001891 0.001740 0.001750 0.001760 0.001760 524288 0.003993 0.003993 0.003963 0.003933 0.003903 1048576 0.007795 0.007242 0.007212 0.007493 0.007192 2097152 0.015309 0.015429 0.015550 0.015359 0.015480 4194304 0.027731 0.027600 0.027660 0.027439 0.027630 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 0.000684 0.000040 0.000060 0.000020 0.000030 8192 0.000141 0.000382 0.000020 0.000020 0.000030 16384 0.000211 0.000201 0.000040 0.000040 0.000040 32768 0.000422 0.000392 0.000070 0.000070 0.000070 65536 0.000996 0.000815 0.000151 0.000171 0.000141 131072 0.001519 0.001589 0.000312 0.000282 0.000292 262144 0.002102 0.001670 0.000654 0.000654 0.000684 524288 0.001247 0.001187 0.001458 0.001227 0.001257 1048576 0.002464 0.002494 0.002625 0.002464 0.002505 2097152 0.004818 0.004788 0.004788 0.004778 0.005019 4194304 0.018014 0.018075 0.018085 0.017964 0.017944 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000493 0.000010 0.000020 0.000020 0.000020 8192 0.000121 0.000020 0.000010 0.000020 0.000010 16384 0.000201 0.000030 0.000030 0.000030 0.000030 32768 0.000362 0.000060 0.000050 0.000050 0.000060 65536 0.000996 0.000121 0.000111 0.000111 0.000131 131072 0.001519 0.000221 0.000251 0.000251 0.000211 262144 0.002535 0.000503 0.000463 0.000463 0.000503 524288 0.001056 0.001217 0.001066 0.000956 0.001036 1048576 0.001851 0.001931 0.001981 0.002042 0.001921 2097152 0.003882 0.003792 0.003903 0.003752 0.003933 4194304 0.007534 0.016435 0.007503 0.015822 0.007503 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000583 0.000040 0.000040 0.000040 0.000070 8192 0.000161 0.000040 0.000040 0.000040 0.000040 16384 0.000272 0.000080 0.000091 0.000080 0.000080 32768 0.000513 0.000191 0.000161 0.000201 0.000161 65536 0.001298 0.000322 0.000312 0.000352 0.000312 131072 0.001951 0.000684 0.000664 0.000614 0.000624 262144 0.002625 0.001348 0.001287 0.001298 0.001287 524288 0.002555 0.002726 0.002585 0.002635 0.002595 1048576 0.005170 0.005210 0.005170 0.005160 0.005160 2097152 0.010270 0.010762 0.010209 0.010410 0.010149 4194304 0.029863 0.029149 0.028998 0.029280 0.029300 Timing results: Vector Size Rep #1 Rep #2 Rep #3 Rep #4 Rep #5 4096 0.000674 0.000111 0.000151 0.000111 0.000101 8192 0.000221 0.000221 0.000181 0.000211 0.000181 16384 0.000453 0.000372 0.000362 0.000372 0.000402 32768 0.000825 0.000754 0.000724 0.000754 0.000754 65536 0.001951 0.001469 0.001509 0.001479 0.001469 131072 0.003158 0.003038 0.002977 0.002927 0.003007 262144 0.006005 0.006055 0.005814 0.005814 0.005834 524288 0.011778 0.011658 0.011587 0.011587 0.011587 1048576 0.023627 0.023476 0.023295 0.023164 0.023275 2097152 0.046600 0.047375 0.047515 0.047033 0.047244 4194304 0.104767 0.106034 0.105481 0.106266 0.105964 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 0.001086 0.000010 0.000010 0.000010 0.000010 2048 0.000091 0.000241 0.000010 0.000010 0.000010 4096 0.000111 0.000091 0.000020 0.000020 0.000010 8192 0.000181 0.000151 0.000020 0.000030 0.000020 16384 0.000583 0.000312 0.000040 0.000040 0.000050 32768 0.000644 0.000634 0.000091 0.000091 0.000091 65536 0.001348 0.001247 0.000191 0.000181 0.000181 131072 0.002655 0.002545 0.000392 0.000372 0.000362 262144 0.000855 0.005049 0.000774 0.000764 0.000734 524288 0.001680 0.010159 0.001559 0.001670 0.001549 1048576 0.003319 0.003269 0.003088 0.003088 0.003078 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 0.001941 0.000191 0.000010 0.000010 0.000010 16 0.000372 0.000322 0.000030 0.000030 0.000030 64 0.005069 0.005321 0.001257 0.001267 0.001308 256 0.119100 0.118336 0.078595 0.079772 0.079561 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 0.000191 0.000262 0.000010 0.000010 0.000010 16 0.142858 0.000020 0.000000 0.000000 0.000010 64 0.000302 0.000030 0.000010 0.000010 0.000010 256 0.000332 0.000221 0.000211 0.000201 0.000211 wtime_test(): Normal end of execution. 08-Oct-2025 02:28:46