Author |
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tony_lincoln
USA
Posts |
Posted - 02/09/2009 : 9:32:40 PM
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Dear Madam/Sir,
I tried to fit curve 1 using single exponential fitting (y=a*exp(b*x) + c) in Origin 8. However, in different computers, I got the different b value: 0.07427 or 0.04141. Then I used another two softwares, ZunZun and GraphPad, I also got different b value, either .07427 or 0.04141. So I am really confused --- which one I shoud choose? What could be the reason to have these two different values?
Curve 1, 2 and 3 have the same y values, I just changed did linear transformation and changed x value in curve 1, and changed it into curve 2 and 3. Curve 1 is the original curve. Another question is, are these 3 curves still the SAME curve?
GraphPad gave me same b value for these 3 curves, but Origin gave me either .07427 or 0.04141 for these 3 curves in 3 different computers.
I really appreciate it if anyone can show me any hints! Thanks.
Curve 1: 24.0860 0.929920 24.6660 0.916290 25.2230 0.901922 25.7400 0.942780 26.3510 0.875073 26.8660 0.955152 27.4850 0.826904 28.0070 0.904872 28.6030 0.879004 29.1490 0.919224 29.6950 0.899116 30.2310 1.00000 30.8100 0.829106 31.3660 0.786188 31.9380 0.852532 32.4600 0.859475 33.0550 0.861591 33.5650 0.848461 34.1790 0.942449 34.7020 0.901296 35.2950 0.994809 35.8140 0.864114 36.4080 0.847948 36.9330 0.796047 37.5010 0.880572 38.0540 0.914439 38.6380 0.779416 39.1860 0.897249 39.7330 0.857322 40.2730 0.792637 40.8580 0.837627 41.3960 0.866486 41.9850 0.787097 42.5140 0.866246 43.1150 0.804120 43.6340 0.835493 44.2290 0.872154 44.7700 0.819632 45.3710 0.835273 45.8930 0.850420 46.5060 0.812996 47.0240 0.887566 47.5950 0.783647 48.1390 0.848138 48.7120 0.852972 49.2500 0.897498 49.7980 0.959756 50.3470 0.924552 50.9310 0.903747 51.4580 0.928523 52.0740 0.776699 52.5940 0.737524 53.1910 0.915994 53.7260 0.906656 54.3220 0.874060 54.8500 0.806015 55.4410 0.833587 55.9770 0.854967 56.5690 0.697498 57.1100 0.810998 57.6790 0.787988 58.2250 0.808483 58.7690 0.795053 59.3120 0.801478 59.9100 0.838632 60.4540 0.811416 61.0310 0.780859 61.5430 0.879334 62.1450 0.846360 62.6640 0.801117 63.2640 0.892933 63.7930 0.851976 64.3900 0.904398 64.9140 0.870151 65.5130 0.840888 66.0320 0.911335 66.6120 0.913124 67.1470 0.881224 67.7230 0.827847 68.2680 0.890090 68.8190 0.829092 69.3600 0.863297 69.9510 0.828419 70.4610 0.935923 71.0620 0.819145 71.5870 0.915325 72.1850 0.910613 72.6930 0.957231 73.3030 0.849726 73.8040 0.918761 74.4000 0.846629 74.9330 0.784890 75.5470 0.927283 76.0650 0.795014 76.6370 0.835413 77.1870 0.767532 77.7600 0.849958 78.3030 0.852627 78.8520 0.812643 79.3990 0.875839 79.9950 0.851806 80.5090 0.853117 81.1080 0.789958 81.6330 0.836185 82.2370 0.710101 82.7710 0.738166 83.3740 0.737436 83.8970 0.861690 84.5090 0.825159 85.0380 0.877351 85.6130 0.848397 86.1530 0.820122 86.7320 0.827983 87.2790 0.785532 87.8320 0.797776 88.3810 0.807236 88.9610 0.919723 89.5080 0.786163 90.0860 0.899443 90.6060 0.862198 91.2090 0.875951 91.7280 0.826531 92.3280 0.848424 92.8310 0.696854 93.4300 0.864295 93.9420 0.887419 94.5610 0.872820 95.0790 0.899159 95.6580 0.816256 96.1910 0.786831 96.7590 0.757777 97.3050 0.814912 97.8750 0.807445 98.4210 0.809484 99.0070 0.819021 99.5250 0.844852 100.124 0.829012 100.632 0.921174 101.237 0.740333 101.749 0.937426 102.372 0.910489 102.948 0.769717 103.546 0.812040 104.062 0.962371 104.674 0.879244 105.211 0.822913 105.796 0.842098 106.340 0.893583 106.894 0.827722 107.433 0.914815 108.018 0.915150 108.536 0.800499 109.299 0.721179 109.805 0.773495 110.955 0.812093 111.555 0.862583 112.081 0.884459 112.679 0.784145 113.222 0.813928 113.798 0.771603 114.349 0.786055 114.906 0.757662 115.446 0.762902 116.023 0.923205 116.540 0.830537 117.144 0.911862 117.662 0.799846 118.259 0.875198 118.770 0.878877 119.405 0.943356 119.975 0.916483 120.592 0.827536 121.106 0.750521 121.677 0.814044 122.219 0.722055 122.799 0.704069 123.340 0.781803 123.890 0.834400 124.427 0.896388 125.014 0.855558 125.553 0.705719
Curve 2: 1 0.92992 2 0.91629 3 0.901922 4 0.94278 5 0.875073 6 0.955152 7 0.826904 8 0.904872 9 0.879004 10 0.919224 11 0.899116 12 1 13 0.829106 14 0.786188 15 0.852532 16 0.859475 17 0.861591 18 0.848461 19 0.942449 20 0.901296 21 0.994809 22 0.864114 23 0.847948 24 0.796047 25 0.880572 26 0.914439 27 0.779416 28 0.897249 29 0.857322 30 0.792637 31 0.837627 32 0.866486 33 0.787097 34 0.866246 35 0.80412 36 0.835493 37 0.872154 38 0.819632 39 0.835273 40 0.85042 41 0.812996 42 0.887566 43 0.783647 44 0.848138 45 0.852972 46 0.897498 47 0.959756 48 0.924552 49 0.903747 50 0.928523 51 0.776699 52 0.737524 53 0.915994 54 0.906656 55 0.87406 56 0.806015 57 0.833587 58 0.854967 59 0.697498 60 0.810998 61 0.787988 62 0.808483 63 0.795053 64 0.801478 65 0.838632 66 0.811416 67 0.780859 68 0.879334 69 0.84636 70 0.801117 71 0.892933 72 0.851976 73 0.904398 74 0.870151 75 0.840888 76 0.911335 77 0.913124 78 0.881224 79 0.827847 80 0.89009 81 0.829092 82 0.863297 83 0.828419 84 0.935923 85 0.819145 86 0.915325 87 0.910613 88 0.957231 89 0.849726 90 0.918761 91 0.846629 92 0.78489 93 0.927283 94 0.795014 95 0.835413 96 0.767532 97 0.849958 98 0.852627 99 0.812643 100 0.875839 101 0.851806 102 0.853117 103 0.789958 104 0.836185 105 0.710101 106 0.738166 107 0.737436 108 0.86169 109 0.825159 110 0.877351 111 0.848397 112 0.820122 113 0.827983 114 0.785532 115 0.797776 116 0.807236 117 0.919723 118 0.786163 119 0.899443 120 0.862198 121 0.875951 122 0.826531 123 0.848424 124 0.696854 125 0.864295 126 0.887419 127 0.87282 128 0.899159 129 0.816256 130 0.786831 131 0.757777 132 0.814912 133 0.807445 134 0.809484 135 0.819021 136 0.844852 137 0.829012 138 0.921174 139 0.740333 140 0.937426 141 0.910489 142 0.769717 143 0.81204 144 0.962371 145 0.879244 146 0.822913 147 0.842098 148 0.893583 149 0.827722 150 0.914815 151 0.91515 152 0.800499 153 0.721179 154 0.773495 155 0.812093 156 0.862583 157 0.884459 158 0.784145 159 0.813928 160 0.771603 161 0.786055 162 0.757662 163 0.762902 164 0.923205 165 0.830537 166 0.911862 167 0.799846 168 0.875198 169 0.878877 170 0.943356 171 0.916483 172 0.827536 173 0.750521 174 0.814044 175 0.722055 176 0.704069 177 0.781803 178 0.8344 179 0.896388 180 0.855558 181 0.705719
Curve 3. 0 0.92992 0.58 0.91629 1.137 0.901922 1.654 0.94278 2.265 0.875073 2.78 0.955152 3.399 0.826904 3.921 0.904872 4.517 0.879004 5.063 0.919224 5.609 0.899116 6.145 1 6.724 0.829106 7.28 0.786188 7.852 0.852532 8.374 0.859475 8.969 0.861591 9.479 0.848461 10.093 0.942449 10.616 0.901296 11.209 0.994809 11.728 0.864114 12.322 0.847948 12.847 0.796047 13.415 0.880572 13.968 0.914439 14.552 0.779416 15.1 0.897249 15.647 0.857322 16.187 0.792637 16.772 0.837627 17.31 0.866486 17.899 0.787097 18.428 0.866246 19.029 0.80412 19.548 0.835493 20.143 0.872154 20.684 0.819632 21.285 0.835273 21.807 0.85042 22.42 0.812996 22.938 0.887566 23.509 0.783647 24.053 0.848138 24.626 0.852972 25.164 0.897498 25.712 0.959756 26.261 0.924552 26.845 0.903747 27.372 0.928523 27.988 0.776699 28.508 0.737524 29.105 0.915994 29.64 0.906656 30.236 0.87406 30.764 0.806015 31.355 0.833587 31.891 0.854967 32.483 0.697498 33.024 0.810998 33.593 0.787988 34.139 0.808483 34.683 0.795053 35.226 0.801478 35.824 0.838632 36.368 0.811416 36.945 0.780859 37.457 0.879334 38.059 0.84636 38.578 0.801117 39.178 0.892933 39.707 0.851976 40.304 0.904398 40.828 0.870151 41.427 0.840888 41.946 0.911335 42.526 0.913124 43.061 0.881224 43.637 0.827847 44.182 0.89009 44.733 0.829092 45.274 0.863297 45.865 0.828419 46.375 0.935923 46.976 0.819145 47.501 0.915325 48.099 0.910613 48.607 0.957231 49.217 0.849726 49.718 0.918761 50.314 0.846629 50.847 0.78489 51.461 0.927283 51.979 0.795014 52.551 0.835413 53.101 0.767532 53.674 0.849958 54.217 0.852627 54.766 0.812643 55.313 0.875839 55.909 0.851806 56.423 0.853117 57.022 0.789958 57.547 0.836185 58.151 0.710101 58.685 0.738166 59.288 0.737436 59.811 0.86169 60.423 0.825159 60.952 0.877351 61.527 0.848397 62.067 0.820122 62.646 0.827983 63.193 0.785532 63.746 0.797776 64.295 0.807236 64.875 0.919723 65.422 0.786163 66 0.899443 66.52 0.862198 67.123 0.875951 67.642 0.826531 68.242 0.848424 68.745 0.696854 69.344 0.864295 69.856 0.887419 70.475 0.87282 70.993 0.899159 71.572 0.816256 72.105 0.786831 72.673 0.757777 73.219 0.814912 73.789 0.807445 74.335 0.809484 74.921 0.819021 75.439 0.844852 76.038 0.829012 76.546 0.921174 77.151 0.740333 77.663 0.937426 78.286 0.910489 78.862 0.769717 79.46 0.81204 79.976 0.962371 80.588 0.879244 81.125 0.822913 81.71 0.842098 82.254 0.893583 82.808 0.827722 83.347 0.914815 83.932 0.91515 84.45 0.800499 85.213 0.721179 85.719 0.773495 86.869 0.812093 87.469 0.862583 87.995 0.884459 88.593 0.784145 89.136 0.813928 89.712 0.771603 90.263 0.786055 90.82 0.757662 91.36 0.762902 91.937 0.923205 92.454 0.830537 93.058 0.911862 93.576 0.799846 94.173 0.875198 94.684 0.878877 95.319 0.943356 95.889 0.916483 96.506 0.827536 97.02 0.750521 97.591 0.814044 98.133 0.722055 98.713 0.704069 99.254 0.781803 99.804 0.8344 100.341 0.896388 100.928 0.855558 101.467 0.705719
Thanks a lot! Tony |
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Deanna
China
Posts |
Posted - 02/10/2009 : 05:02:20 AM
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I got the same B value (.07427) on multiple computers. I am not sure why this happens to you. Could it be caused by different initial values? Initial values are values assigned to the parameters when the fitting begins. It could also be caused by different settings.
Please try to use the ExpDEC1 built-in function to test on your computers and tell us whether the results are the same.
Also, I suggest patching to SR4, which is the latest SR.
Deanna OriginLab Technical Services |
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easwar
USA
1964 Posts |
Posted - 02/10/2009 : 10:44:00 AM
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Hi,
Also note that the fitter has maximum iteration and tolerance settings. The iterative procedure stops when tolerance is met (chi-sqr does not reduce any further within speficied tolerance) OR if maximum iterations is met.
So when you get different values, it is possible the max iteration or tolerance values were different on these machines, so please check that to see they are same.
You can change these settings such as setting a higer max iteration number. The controls are under teh Settings->Advanced->Fit Control branch (assuming you are using version 8) of the fitter tool.
Easwar OriginLab |
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tony_lincoln
USA
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Posted - 02/10/2009 : 11:25:33 AM
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Thanks for the quick reply. I really appreciate it. One question to Deanna: Did you try ALL 3 curves? In my computer, for curve 2, I got 0.04141. For curve 1 and 3, I got 0.07427. So I should use 0.07427 I think. easwar's suggestion sounds reasonable. I should try to set a higer max iteration number. Thanks a lot Tony |
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Deanna
China
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Posted - 02/10/2009 : 9:51:18 PM
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The 3 curves are different, because the relationship betwen X and Y is not linear in the exponential fitting function (y=a*exp(b*x) + c). Changing X will yield different fitted parameters.
By using the ExpDEC1 function, which is built-in, I got: A1 = 0.48888 for the first curve; A1 = 0.0851 for the second curve; A1 = 0.08182 for the thrid curve.
Deanna OriginLab Technical Services |
Edited by - Deanna on 02/10/2009 10:25:45 PM |
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