Equation List

The Equation List window displays a selection list of the surface-fit equations. This list will initially be sorted by the criteria set in the Surface-Fit Preferences Process menu option. This list can subsequently be sorted by any one of TableCurve Studio's four goodness-of-fit sort criteria, by floating point execution speed, or by equation number, and its content can be filtered to only contain certain types of equations.

The Equation List window will have its own menu if it is sufficiently large. If you choose to have the Equation List displayed in a small window, its content-related functions can be accessed via the List menu in the Surface-Fit Graph window. The Equation List is toggled on and off by the List button or the Equation List Window menu item in the Surface-Fit Graph window. You may also close the Equation List window directly using its system menu.

The window size and position you choose for the Equation List is automatically saved across sessions. TableCurve Studio saves two Equation List window positions and sizes, one for the Graph Start option and one for the List Start option. Options to save the Equation List to a file, to display the list in color, and to print all or part of the list are present only in the List Window's own menu and not in the List menu of the Surface-Fit Graph. To access these functions when the Equation List is too small to have a menu, simply maximize the Equation List window.

Rank

The first item in each line of the equation list will be the ranking of the equation by the goodness of fit criteria currently set. Initially, all successfully fitted equations that have been added to the list are shown. The rank will always reflect the position within all fitted and saved equations, regardless of how the list is filtered.

Goodness of Fit

The second item will be the goodness of fit value. This may be the rē coefficient of determination, the DOF-Adjusted rē, the Fit Standard Error, or the F-statistic. The current goodness of fit criteria will be shown in the window's title bar. When the All Goodness of Fit in List option in the List menu is checked, all four goodness of fit statistics will be displayed within the equation list.

Floating Point Demand

The third item will be the FP or floating point demand for the TableCurve Studio generated language code for this equation. A value of 1 corresponds to 1 floating point addition. The higher the number, the greater the execution time for the equation code. These values are based on a 486 chip with its internal math coprocessor.

Equation Number and Equation

The last items in an equation list entry will be the TableCurve Studio equation number and the equation expression.

Selecting an Equation

If you make a selection from the Equation List using a mouse, an equation is selected as soon as you click on it. All Review windows currently open will be updated to reflect the new equation. If the Equation List is the currently active window, you may also move through the list using the cursor keys and make a selection by pressing Enter. If you maximize the Equation List window, regardless of Review startup option, the Equation List window is automatically closed when a selection is made.

File Menu

The Save As option is used to save the Equation List to an ASCII file (comma separated CSV, tab separated PRN, or space formatted TXT), or to a fully formatted Rich Text Format (RTF) file. In the case of the ASCII files, superscripts are not preserved.

A save to the RTF format seeks to exactly preserve the appearance of the equation list when imported into word processing and desktop publishing products. This option preserves columnar formatting, font colors, bolding, superscripts, and subscripts. In order to save a black and white RTF text file, you will need to uncheck the Color option in the List menu.

Use the Printer Setup item to select the current printer and optionally to configure the printer's own driver.

The Print item is used to print either the currently displayed contents of the list, or the entire list. The Text Print dialog is used to customize the printing of the information.

Edit Menu

The Copy option copies the full equation list, memory permitting, to the Windows clipboard as unformatted text, as comma separated (CSV) text, and as formatted Rich Text Format (RTF) text. The unformatted text format is tab delimited and is used when you paste the equation list into a text-based program.

The RTF format seeks to exactly preserve the appearance of the list when pasted into word processing and desktop publishing products. The RTF format preserves columnar formatting, font colors, bolding, superscripts, and subscripts. In order to save a black and white RTF text file, you will need to uncheck the Color option in the List menu prior to the Copy.

For some products where RTF is the default clipboard format, such as Microsoft Word, you will need to use a Paste As, Paste Special, or similar option in order to specifically select the unformatted text. When you paste the equation list into a spreadsheet, the columns are separated into cells.

The ASCII Editor option copies the equation list into the TableCurve Studio ASCII editor.

List Menu

When the Keep List After Selection is checked and the Equation List window is not maximized, the Equation list is not removed after a selection is made. If this Keep List After Selection is not checked, or if the Window is maximized, the Equation List window is closed after each selection.

When the All Goodness of Fit in List option is checked, all four goodness of fit statistics will be displayed within the equation list. First will be the rē coefficient of determination, then the DOF-Adjusted rē, the Fit Standard Error, and finally the F-statistic.

The style items include setting a font for the list. This Font for List font selection is unique to the Equation List. The Color option toggles the display of the list between color and black and white.

Filter Menu

All of the Filter Menu items are also in the Surface-Fit Graph's List menu. You may apply six different filter options to the equation list so that it contains All Equations, only the three parameter Simple Equations, only Polynomial/Rational Equations, only Polynomial Equations, only Rational Equations, or only Non-Linear Equations. These options reset the selected equation to the first within the list.

Sort Menu

All of the Sort Menu items are also in the Surface-Fit Graph's List menu. You may sort the current list at anytime by r2 coefficient of determination, by DOF-Adjusted r2, by Standard Error (Root MSE), by F-statistic, by Floating Point Speed, or by TableCurve Studio Equation Number.

If you want the best possible least squares fit, use either the DOF-Adjusted r2 or the Standard Error criteria.

If you want the equation which represents the best possible model for describing the data, use the F-statistic. The F-statistic sort will often bring many simpler equations nearer the top of the list if the equations do a respectable job describing the data using a modest number of coefficients.

The Arrange by Parameter Count option will use the coefficient count as the primary sort key, and the selected goodness of fit sort criterion as the secondary key. When this option is selected, all of the three parameter fits will be at the top of the list. Within each parameter count grouping, the equations will be sorted by the currently selected goodness of fit.

 A sort always resets the selected equation to the first equation in the list.

For 2D (XY) Data

For a 2D (XY) data item the Equation List window works the same way, with these differences.

By default, rational equations with a pole or undefined region in the X-range of the data are excluded from the list. Toggle the Rationals Fully Defined Xmin-Xmax item in the List menu to include them.

The goodness-of-fit value can also be the Maximum Error, in addition to rē, DOF-Adjusted rē, Fit Standard Error, and F-statistic, and the Sort menu can sort by Maximum Error as well.

The Filter menu offers two additional filters beyond the equation-family filters: Continuous Trend First Derivative (equations whose first derivative is continuously increasing or decreasing across a specified X-range), and Constant Sign First Derivative (equations whose first derivative keeps a constant sign across that range). Use the Set X Range for Derivative Filtering option to set the X range and the number of sampling points scanned for these two filters; the default scans Xmin to Xmax plus half the X range, at 32 points, and scanning time is linear in the number of points. The same default pole-exclusion for rational equations is also controlled from the Filter menu, as Rational Defined Xmin to Xmax.

The File menu's Save As option additionally offers Lotus WK1, WK3, and a partially formatted Wordstar file that retains superscripts and subscripts; superscripts are not preserved in plain ASCII, WK1, or WK3. The Edit menu's Copy option additionally places the list on the clipboard in Lotus WK1 format, and its unformatted text is space-delimited rather than tab-delimited.