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Contents → Fitting → sa save data points

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lists the current data points to the screen or to a file, just as its does in the plot program. There is a difference in the format, though, when the points are written to the screen.

sa
or
sa filename [a|w]

Refer to the description of sa in Chapter 3 for an explanation of this command. The difference in screen format from the plot program version of sa is shown in the following example. (The data presented here is used in the straight-line fit examples elsewhere in this chapter.)

x     y         weight     yfit       residual
10    48.9343   0.142953   50.4044     0.210153
11    56.32     0.13325    54.4217    -0.252944
12    53.9749   0.136114   58.4391     0.607637
13    67.6994   0.121537   62.4564    -0.637217
14    73.7787   0.116422   66.4738    -0.850451
15    80.0557   0.111765   70.4911    -1.06898
16    69.4587   0.119988   74.5085     0.605915
17    64.9841   0.12405    78.5258     1.67984
18    72.0632   0.117799   82.5432     1.23454
19    99.7246   0.100138   86.5605    -1.31823
20    98.2006   0.100912   90.5779    -0.769229

The second to last column is the value calculated using the model equation and the current parameters. The last column is the weighted residual, w_i(y_i - yfit_i).

The sa command in the plot program produces the following for the same data.

10    48.9343   6.99531
11    56.32     7.50469
12    53.9749   7.34678
13    67.6994   8.22795
14    73.7787   8.58944
15    80.0557   8.94734
16    69.4587   8.33417
17    64.9841   8.06126
18    72.0632   8.48903
19    99.7246   9.98622
20    98.2006   9.90962

Here the third column is the error-bar value rather than the weight (which is the inverse of the error-bar value).

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