GUM Calculator

• Implement Excel import formats (version 2 feature—BETA). These allow one to import data into a model directly from a Microsoft Excel spreadsheet rather than a CSV file.
• Implement CSV files with UTF-8 encoding, compatible with the most recent versions of Microsoft Excel (the CSV UTF-8 file type).
• Implement the operator @wavg(x₁,x₂,…) for calculating the uncertainty-weighted average of one or more variables, with or without correlations. This calculation is optimal only when the uncertainties represent true standard deviations. For example, it is usually possible to do better when averaging results from nuclear counting measurements. Contact the developer if you have questions.
• Implement the operator @chisq(x₁,x₂,…) to calculate the chi-squared statistic associated with @wavg(x₁,x₂,…).
• Implement the operator @df(x₁,x₂,…) to determine the degrees of freedom for @wavg(x₁,x₂,…) and @chisq(x₁,x₂,…).
• Correct issues with the substitution of punctuation marks ‹ and › (U+2039 and U+203A) for missing font characters 〈, 〉, ⟨, and ⟩ (U+2329, U+232A, U+27E8, and U+27E9).
• Provide a new function zeta(x), which returns the standardized score for a variable x, equal to x/u(x).
• Loosen some restrictions on the use of the @ character in an identifier. Also print the @ character unchanged when it occurs in a variable identifier instead of displaying it as function application. It will still be displayed as function application when it occurs in a library constant.
• When an import data file is opened or a template data file is created, add the file to the Windows list of “Recent files.”
• Provide aliases for certain library functions: ln(x)=log(x), Γ(x)=gamma(x), Β(x,y)=beta(x,y), λ(x)=lambda(x), ζ(x)=zeta(x), ϱW(T)=rhoW(T), chisq(u,n)=χ2(u,n)=chi2(u,n), chisqtail(x,n)=χ2tail(x,n)=chi2tail(x,n), urel(x)=ur(x), urel2(x)=ur2(x). The aliases, like the original function identifiers, can be overridden within a model.
• Change the display of a measured result that has been rounded to 0 with uncertainty greater than 10, omitting extra leading zeros—e.g., 0±38 instead of 00±38, and 0(19) instead of 00(19).
• Interpret the keystroke Ctrl+A to mean “Select All” in an edit control, providing Ctrl+Shift+S for the File “Save As” function.
• Update some of the nuclear data.
• Update the Help system.
• Use the latest C++ std implementations of the functions expm1, log1p, atanh, asinh, and acosh (with others to follow).
• Debug the version 2 functions decayn and decaya for long-lived progeny.
• Implement new version 2 functions decaym, ratiom, and eqrm, similar to decayn, ration, and eqrn but based on mass ratios.
• Change the autocorrection feature for subscript digits to trigger on a backslash (e.g., x\1 → x₁) rather than an underscore (x_1 → x₁).
• Make minor cosmetic changes.

• Implement the 2019 revision of the International System of Units and the CODATA 2018 adjustment of the fundamental constants, both of which were effective May 20, 2019.
• Provide the Rydberg constant, R_∞, as one of the primary experimental constants on which the values of others are based. Revise the definitions of other constants accordingly.
• Revise the symbols for several constants, using the period implemented in 0.99.9 instead of the underscore to denote a subscript. If the symbol for a constant has a subscript, do not italicize the subscript when printing. For example, the symbol for the electron’s mass will be m.e, not m_e as in earlier versions, and it will be printed as m_e.
• Make the lists of editable constants, units, and distributions sortable on all columns.
• Correct a bug that led to crashes after deleting a constant on which the values of other constants depended.
• Prohibit the use of all units except SI base units and their multiples and submultiples in expressions for user-defined constants. This limitation was previously assumed but not enforced.
• Correct a problem with how the program wrote, read, and interpreted the file of nuclide data, failing to obtain the correct uncertainty for m(¹²C).
• Allow more kinds of characters in identifiers, including Unicode subscript digits (e.g., a₁). Provide user-reversible auto-correction to generate subscript digits when the user types an ordinary digit after an underscore.
• Provide a new version 2 function to calculate the density of air-free water at a specified Celsius temperature using the Tanaka equation.
• Make several cosmetic changes.

• Update the constant library with new values from CODATA 2014. Update the definitions of the astronomical unit (au) and parsec (pc).
• Correct a bug that makes it impossible to use the correlation coefficient for one pair of constants or variables in the definition of the correlation coefficient for another pair of variables. Previous versions treat this as a circular definition, even when it is not. Worse, they leave the r(x,y) library function flagged as unusable until the program closes.
• Change the implementation of the file Save As dialog, updating its appearance and changing how it provides default file extensions (with a new workaround for some deficiencies in the Microsoft API).
• Allow many of the windows to be resized.
• Reverse the order of updates listed when a user checks for updates and clicks the Details… button, showing the most recent update first.
• Make several enhancements of the program’s icons and bitmap images, including those on the toolbar.
• Let the user choose the font for displaying special Unicode characters.
• Correct a minor bug in the implementation of auto-completion lists. The bug, which was introduced in 0.99.8, causes the up and down arrow keys to work incorrectly with the list of suggestions.
• Make the printing of uncertainty budgets optional in each user-defined report.
• Enhance the XML import feature (version 2), allowing the user to specify the XML tree structure by selecting an existing XML data file as an example. Modify the XML import logic slightly to implement a different trigger condition for generating output. Provide more error-checking and some enhancements in the user interface (e.g., more drag-and-drop operations and new buttons for editing import units and date format strings). Expand the explanation of XML import formats in the Help system.
• Provide a new (version 2) function for the natural isotopic abundance of a nuclide.
• Provide the symbol ℯ (U+212F) for Euler’s number with ⅇ (U+2147) as a synonym, instead of the lower-case Latin e (U+0065). Will define e instead to mean the elementary charge (charge of a proton). The symbol for Euler’s number will still be printed—correctly—as an upright small Latin letter e.
• Provide keyboard sequences for several Unicode combining diacritical marks, including accents grave, acute, circumflex, tilde, umlaut/diaeresis, cedilla, macron, breve, ring, caron/háček, and a few others. Allow these accents to be used in identifiers.
• Eliminate the auto-correct sequences \| and \& for Boolean ∨ and ∧, retaining the sequences || and &&.
• Test a new design that uses a period to introduce a subscript in a variable or function identifier (e.g., c.A to represent activity concentration, c_A).
• Improve the formatting of identifiers in printouts, implementing subscripts as described above and ensuring that non-alphabetic characters are not italicized. (For now, there is still no way for the user to override the rules for use of italics.)
• Automatically wrap long printed equations.
• Implement the Ctrl+Up arrow and Ctrl+Down arrow key combinations to change the case of selected text, with support for basic Latin, Greek, and Cyrillic letters and also many accented Latin letters.
• Provide auto-correction of &-sequences inside quoted strings, leaving the user the option to press Ctrl+Z to undo the auto-correction if necessary.
• Allow the use of the backslash character (\) inside a quoted string as a prefix for a literal character, as in “William F. \“Bull\” Halsey, Jr.”
• Implement the Alt+X key combination to toggle Unicode representations of selected text.
• Revise the 0.99.3 implementations of Ctrl+Right arrow, Ctrl+Left arrow, and double-click, which were never satisfactory.
• Correct a few errors in the nuclide database, and add information.
• Implement a new version 2 feature for exporting results to XML files.

• Corrects an obscure bug that revealed itself only if you ran the program with a unit library that omitted the becquerel (Bq).
• Corrects a bug that caused the program to omit the parentheses in an expression like Ar(O) in a printed uncertainty budget. In version 0.99.7 this expression appeared incorrectly as ArO, although the relative atomic mass of a nuclide, such as Ar(3H), was printed correctly.
• Provides an option to have GumCalc check for available updates automatically at start-up, on a user-specified schedule.
• No longer displays an annoying auto-completion list when the user types the e in a floating-point number using scientific notation (e.g., 1.57e-4).
• Makes it easier to find components in the tree view of a large model. It allows the user to right-click a reference to a model variable or function and have the program find and highlight its definition in the model tree. It also provides an option to list components alphabetically under each node. And it provides an option to group model variable definitions by type (import, text, input, output).
• Includes several other changes in the implementation of the tree view and tabbed view of a model. These changes are intended to correct oversights, make the interface more user-friendly, and simplify the code that coordinates the updating of each view. The method for renaming a function has been simplified, eliminating the dialog box used in earlier versions. Although the tabbed view is still provided, the tree view is fully functional.
• Fixes a previously unrecognized bug that may have caused occasional invisible program crashes when the user tried to exit while a document was still open. The only apparent symptom would be the loss of unsaved changes, where the program failed to prompt the user to save a modified document. I still consider this bug to be an error in the Microsoft framework itself, which would sometimes delete an object and then try to reference it via a dangling pointer.
• Corrects an almost completely inconsequential bug in the implementation of auto-correction for the dialog box that is used to create and edit functions.
• If the column labels in a CSV import file match the expected labels of the current import format only partially, the program gives the user the option of updating the import format to match the labels in the file (exactly).
• Provides configuration options for showing or hiding various windows at startup. All versions to date have automatically displayed the “Evaluation” window, which might prevent inexperienced users from exploring other features.
• Makes slight changes in the format of printed reports.
• Implements the menu items Help | Library constants, Help | Library functions, and Help | Library units using MDI child windows instead of modeless dialog boxes. The MDI windows do not force themselves to the front of other child windows.

• Corrects a bug that was triggered in the tabbed view of a model when a user attempted to switch tabs while still editing the label for an item (i.e., when renaming a variable). This may be the same bug that I first thought might be related to reopening and editing a new report, since I discovered it while trying to do just that. The most obvious symptom was an immediate program crash, but other symptoms may also have been possible.
• The implementation of pop-up prompts for function arguments in 0.99.6 created a bug that affected the dialog box for editing a CSV export format, sometimes causing the program to display incorrect pop-up lists. Version 0.99.7 corrects the bug.
• Removes minor glitches in the autocorrection features in some of the edit controls.
• Corrects a bug that would trigger the message DEBUG: Unexpected situation. Programmer error? when the user entered an invalid unit expression in the Evaluation window and pressed ENTER. (It was indeed a programmer error.)
• Provides an option to duplicate a model component, creating a new unnamed copy, which the user can either edit and save or discard.
• Re-implements the operators ∂(y,x), @ui(y,x), and @ui2(y,x) in a way that allows them to accept an arbitrary expression as the second operand x as long as the value of x depends on just one input quantity. The old implementations required x to be the symbol for an input quantity. The new implementations allow one to evaluate an expression like ∂(decay(“Cs-137”, 180{d}), HalfLife(“Cs-137”)) or even ∂(decay(“Cs-137”, 180{d}), lambda(“Cs-137”)).
• Makes auto-completion listboxes (auto-lists) optional. They are still enabled by default. To disable one or more of them, see Tools | Options | Preferences.
• No longer supports the syntax @sum(i,a,b)(e) and @prod(i,a,b)(e), as mentioned under 0.99.3 below. Use ∑(i=a:b)(e) and ∏(i=a:b)(e) instead. I expect to continue supporting the alternative syntax ∑(i=a,b)(e) and ∏(i=a,b)(e), too.
• Provides better, more specific user error messages for invalid operations.
• Improves the data grid used for editing CSV export formats and the data grid used for editing unit definitions.
• Version 2 features now include a function chi2tail(x,n) for calculating the tail probability of a χ² distribution with n degrees of freedom and also a function chi2(q,n) for the inverse operation χ²_1−q(n). Note that chi2tail(x,n) = Q(n/2,x/2) and the function Q(a,x) was already available as a Version 1 feature.

• Corrects a bug that would crash the program when the user opened or created a model containing a correlation definition, evaluated an expression, deleted the correlation definition, and then tried to evaluate any expression that required that correlation coefficient.
• Corrects an oversight that would leave the image of an open folder displayed for a component group in the tree view of a model even after the user deleted the last item from the group.
• Provides automatic syntax upgrades for old function definitions that use < and > as angle brackets. (I think I had provided them for every other type of model component but had forgotten to provide them for function definitions.)
• Provides some missing functionality in the edit control used to specify the preferred unit for an output quantity.
• Allows reporting of a model variable using an appropriate unit of measurement even when the user’s preferred unit has the wrong dimension for the quantity.
• Provides more contextual information with many of the user error messages to help users debug their models.
• Improves the export feature with a few tweaks, although it needs much more than tweaks.
• Implements a pop-up window to prompt the user for arguments when typing a function invocation.
• Includes a few previously missing &-entities (e.g., ξ = ξ, — = —, and – = –) and the corresponding TeX control words (\xi, \mdash, and \ndash).

• Corrects errors in the user interface for creating and editing correlations between library constants (Tools | Edit constants…).

• Disables TeX-style control words and control symbols in edit controls used for the names of files and folders.
• Improves accuracy of the last (15th or 16th) digit when numerical results are formatted for display without uncertainty.
• Allows a model to continue running after a CSV data-import error and improves the presentation of the error message in the printed output.
• Produces more specific user error messages for CSV import failures.
• Improves the operation of auto-completion listboxes, making better use of the context to choose the highlighted item and replacing more text when the selected item is accepted.
• Autocorrects Ω to Ω (U+03A9), not Ω (U+2126), so that Ω really is equivalent to Ω, as previously advertised.
• In the form used to edit a CSV import format, provides a workaround to keep the OK button from canceling an active edit operation. (This perverse behavior had been a problem for years, but I never noticed it until I was testing another feature with a very small import format.)

• Corrects a bug in the Tools | Edit constants… feature that could cause some constants not to appear in the list or cause the program to crash when displaying the list.
• Corrects an oversight that prevented evaluation of the average (@avg) of a list of dates or a list of temperatures.
• Corrects an oversight in the implementation of the ration function (version 2) that prevented the calculation of atom ratios for long-lived progeny.
• Corrects a minor bug that affected the appearance of Euler’s number e in printed reports.
• Detects overflows in rational arithmetic and switches to floating-point arithmetic when necessary.
• When renaming variables, provides warnings for conflicts between new variable symbols and other identifiers (function parameters and the iterators in n-ary sums and products).
• Provides more warnings for attempts to perform invalid calculations with dates or temperatures.
• Provides TeX-like control words for typing non-ASCII Unicode characters. HTML-like &-entities were already provided for the same purpose.
• Emulates certain TeX control symbols for adding Western European accents to letters (e.g, \'e to produce é).
• Tries to provide better feedback for user syntax errors.
• Provides a sign function to tell the sign (−1, 0, or +1) of a scalar quantity, ignoring its unit of measurement.
• Provides Boolean constants true and false, relational operators (e.g., ≤ and ≠), and logical operators (e.g., ∧, ∨, ¬) for constructing Boolean expressions. Provides keyboard sequences for typing the new symbols using auto-correction (e.g., <= for ≤, <> for ≠, \& for ∧, \| for ∨, ~ for ¬).
• Makes another small change in the syntax for n-ary sums and products. The preferred syntax is now ∑(i=a:b)(e) for sums and ∏(i=a:b)(e) for products, although ∑(i=a,b)(e) and ∏(i=a,b)(e) will still be accepted, probably in perpetuity, since I am still in the habit of using them, and since parsing them is easy. The original forms @sum(i,a,b)(e) and @prod(i,a,b)(e) are deprecated and will soon be unsupported. My code for parsing those forms has always been inelegant and I want to deep-six them.
• Replaces the symbols < and > previously used as angle brackets with actual angle brackets ⟨ and ⟩, allowing < and > to be used as relational operators. Provides keyboard sequences \< and \> for typing the angle brackets using auto-correction. For compatibility with Windows and Arial Unicode MS, the keyboard sequences generate the deprecated characters U+2329 and U+232A instead of the preferred characters U+27E8 and U+27E9, but the parser considers U+2329 ≡ U+27E8 ≡ U+3008 and U+232A ≡ U+27E9 ≡ U+3009.
• Provides better spell-check suggestions for identifiers that contain accented letters, ligatures (e.g., æ and œ), or certain foreign letters that may be transliterated as two English-Latin letters (e.g., Ch for Č).
• In version 2, provides C-style conditional evaluation operators (e.g., m ≤ R ? 1 − m / (2 × R) : R / (2 × m)). Note that version 2 features are accessible only with a user-specific key code.
• Provides a new version 2 function to calculate the theoretical maximum relative mass yield of a chemical product from a chemical reactant; e.g, yield(“KIO3”,“PdI2”) or yield(“KIO3”,“PdI2”,“I”). Use the 2-parameter version if the reactant and product have only one element in common. Otherwise, use the 3-parameter version to specify a shared element on which to base the calculation.
• Provides a Details... button for obtaining additional information about available software updates.
• Makes it slightly easier to create a new component in the tree view of a model by enabling the New operation whenever an existing component is selected.
• Provides new event handlers for Ctrl+Right arrow, Ctrl+Left arrow, and double-click in edit controls. I found the old ones annoying, especially Ctrl+Right arrow and Ctrl+Left arrow.
• Makes several significant changes in the expression-parsing algorithm, primarily to remove old kludges and simplify the code.

• Version 0.99.2 was an incomplete implementation of 0.99.3. I gave it to only one person and then incremented the version number.

• Avoids crashes caused by certain mouse-over tooltips
• Removes a bug that caused incorrect selection of preferred units for radionuclide half-lives (due to an embarrassingly obvious mistake in the code, which I discovered when I added the ampere-hour to my unit library)
• Avoids errors triggered when a user renamed any constant upon which another constant’s definition depended
• Correctly propagates uncertainty for the expm1 function
• Corrects errors and omissions in the history of US daylight saving time
• Provides menu icons (still subject to change)
• Allows user to check for software updates
• Provides autocompletion lists for unit symbols
• Provides more complete implementation of autocompletion and autocorrection features throughout the program (e.g., in combo boxes, list controls, and tree controls)
• Labels columns in uncertainty budgets more appropriately
• Provides header sort buttons for the tables of constants, library functions, and units under the Help menu
• Provides a more compact context menu for inserting special characters into edit controls
• Includes additions and corrections in the help system
• Provides a Help Favorites tab
• Implements the log1p function (because I found the standard C/C++ version of log1p useful when implementing some of the decay/ingrowth functions)
• Uses a new algorithm for dealing with certain sets of correlated input estimates (e.g., decay branching factors whose sum is 1)

• Implement the four new prefixes added to the SI in 2022.
• Implement the CODATA 2022 adjustment of the fundamental constants.
• Correct a bug in the interface for pop-up suggestion lists that was introduced in the most recent build.
• Provide a simple calculator capability when entering numerical values for user-defined constants and units.
• Simplify the interface for editing the definition of an input quantity.
• Provide a Download button to download the software installer package for a GumCalc update without visiting mccroan.com.
• When checking for updates automatically, use a notification area icon and balloon tip to notify the user that an update is available. Display a pop-up menu of options if the user clicks the icon.
• Edit several of the definitions for measurement units, recognizing fewer off-system units as accepted for use with the SI, and add a few more off-system units.
• Use the Consolas font for better readability of date format fields and of the key value that unlocks Version 2 features.
• Add the cbrt (cube root) function to the function library.
• Correct transitory problems that occur with the display of some windows whenever the user chooses a different font for math and special characters.
• Change the % of variance column for an uncertainty component in an uncertainty budget to the percent of the total uncertainty, u_i(y) / u_c(y).
• Automatically disable the startup dialog box for new users the first time the user opens the Help library (if that ever happens).
• Update the Help system.

• Update the Help system further. Replace a few more outdated screen captures.
• Provide options to use pipes (|) or semicolons (;) instead of commas as delimiters in CSV import and export files.
• Provide user-configurable options for the types of information to be shown in an uncertainty budget (e.g., relative uncertainty component, percent of variance, percent of total uncertainty).
• Provide pop-up suggestion lists for @ keywords and operators such as @now, @user, @avg(…), and @stdev(…).
• Provide a small collection of pre-defined models as examples for new users.
• Improve the dialog boxes for measurement units and date formats associated with a CSV or XML import format, using data grids similar to the one now used for editing an Excel import format. Improve the dialog box for a CSV export format in the same manner.
• Provide features for editing tabular import data files (CSV or Excel).
• Provide more powerful version 2 features for importing data from an Excel workbook using named cells, ranges, and tables on multiple worksheets. The motivation would be to provide a tool to validate workbook calculations at a laboratory, e.g., for sample analysis and instrument calibration. The coding changes would be extensive and would affect both reports and exports.
• Provide more sophisticated report formats.
• Provide an option to find all references to a selected variable or function.
• Provide a feature to search for arbitrary text strings in a model—e.g., in the descriptions of variables and functions.
• Enhance the nuclide browser to show the parents and daughters of the currently selected nuclide and to allow navigation forward and backward along the decay paths (version 2).
• Provide a capability for users to build their own function libraries (version 2).

If you encounter an error, please report it, especially if you can tell me how to reproduce the symptoms so that I can find the cause and correct it.