12/16/2023 0 Comments Results log .txt scidavis(see Assign Formula command from the Matrix menu) A GraphĪ graph can contain one or several plots. In the same way as for tables, you can also fill matrix with the results of a function z=f(i,j) in which i and j are row and column numbers, or z=f(x,y). If you want to read a matrix from an ASCII file, you can import the data of the file to a table with the Import Ascii command and then convert this table to a matrix with the Convert to Matrix command. Nevertheless, you can specify the X-values and the Y-values with the Set Coordinates command command from the Matrix menu.Ī matrix can be created by the New→New Matrix command. It contains Z-values and doesn't include any column or row which could be designed as X-values or Y-values. The last way to enter your data is to fill the table with the results of a mathematical function ( Assign Formula command from the Table menu) MatrixĪ matrix is a special table which is used to store the data points for surface 3D plots. You can also enter each value from the keyboard, or copy and paste from another spreadsheet software. If you want to read a table from an ASCII file, you can import the data from the file to a table with the Import Ascii command. Then there are several ways to fill the table with your data. In addition, columns can be labelled as errors on X or on Y values (see Set Column as command).Ī table can be created by the New→New Table command. In each table, columns can be labelled as X-values or Y-values for 2D-plotting, or Z-values if you plan to build a 3D-plot. It can also be used to do some calculations and statistical analysis of datas. PS: The behaviour above i seen in both 2.3.0 and 1.26 versions, independently of OS (tried Linux (debian), Mac OS and Windows 10).A table is a spreadsheet which can be used to store the datas you are entering. This bug seems to be only related to fits where yErr are requested to be taken into account. However, user-defining an identical function y0+A*exp(-x/t), only the Nelder-Mead Simplex succeeds, while the Levenberg-Marquardts end up with "iteration not making progress towards solution" and report fit-parameter values different from N-M Simplex. PS: Strangely, when trying polynomial fits instead of the exponential one, the results match including the fit-parameter uncertainties.Īd 2) When playing with the fit options, we have also met another strange behaviour in SciDavis: when fitting the built-in ExpDecay1 function, all three algorithms (Scaled/Unscaled Levenberg-Marquardt and Nelder-Mead Simplex) report sucess and same results. The fits account for the y-uncertainties yErr, however, similar discrepancy is seen when doing unweighted fits. I.e while the central values match, the uncertainties do not. However, using the SciDavis ExpDecay1 the results (both Scaled/Unscaled Levenberg-Marquardt and Nelder-Mead Simplex) are: The results from GnuPlot, python-scipy and are: The data we are trying to fit are: xĪd 1) We are trying to fit these data using an ExpDecay1 function, i.e. When using built-in function, the fit dialog does not offer possibility to fix parameters. Using a built-in function and identical user-defined function exhibits variations in the fit behaviour. The results, namely the fit-parameter errors are not matching results from other programs (GnuPlot, python-scipy,, where the results are identical). Trying to fit data with an exponential function, we have met with several problems, in summary:
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |