Release 0.9.20 "Corpus" - Polynomials and algebraic expressions

[c3d]

This release focuses on support for polynomial, root finding and algebraic expressions, and on making evaluation of algebraic expressions behave closer to algebraic mode on the HP50G, i.e. treat ' like the HP50G treats a backquote expression or an expression entered in algebraic mode.

New features

• LU command generating LU-decomposition for matrices
• REF, RREF and RREFP commands to put matrices in Echelon form
• Order command to reorder variables in the current directory
• PEval, PRoot and Zeros commands for polynomials and expressions
• Unique and QuickUnique commands to keep unique values in a list
• DEPND and INDEP commands to set dependent/independent variables
• Implicitly recognize xlib and constants by name, e.g. c or Dedicace
• Flags to control the above, AutomaticConstants and AutomaticXLibs
• Preserve symbol case for existing variables
• Creating symbols matching builtin names using the Ⓥ prefix, e.g. ⓋHelp
• Value comparison for Sort or Unique now works with expressions
• Simplification now factors common ratios, e.g. A*X+B*X
• Primitive and derivative of a polynomial
• Several new constants lifted from the R47 constant catalog
• Hyperbolic secant functions sech,csch, coth, and their inverse
• CrDir can now take a list as input to create multiple directories

Bug fixes

• Crash in solver in case of error evaluating some intermediate step
• Correctly put parentheses in 'sin(x+1)' rendered in text mode
• Occasional object_error in as_text() on simulator
• Crash in IFT / IFTE if given invalid input
• Detection of expression vs. RPL programs during evaluation
• Crash in quotient or decimal conversions given erroneous input
• Parsing of 0+ⅈ, was incorrectly parsed as 0ⅈ
• Negating 0 no longer shows -0
• No longer allow incorrect mixing of ranges and uncertain numbers
• Dividing a polynomial by a number now divides constant terms
• Correctly split expressions that contain a single term when testing equations
• Fix simulator race condition while loading the keymap
• STO will no longer overwrite a directory with a non-directory value
• Purge will no longer erase non-empty directories, PGDir is now needed
• RAr constant uncertainty was incorrectly set to 0
• Swap keyboard legacy and 42k keymaps in simulator

Improvements

• Purely imaginary values such as 0+3ⅈ now render as 3ⅈ
• The LNAME command now returns a list in algebraic expressions
• Σ, ∏, ∂ and ∫, COMB and PERM now partially evaluate as on HP50G
• Refactor detection of symbolic arguments in functions for scalability
• Refactor detection of algebraic functions for scalability
• Signal when ui_refresh() takes too long due to internal race condition
• Do not drop input in multisolver when a wrong value is given
• Quick exit when parsing empty commands
• Rounding for →ℚ more accurately respects displayed precision
• Internal factoring with square roots and fractions to_sqrt, used in PRoot
• Internal integer and fraction square root, used in simplification
• Reorganize the polynomials menu to bring useful functions at first level
• Accept polynomials and tagged expressions in plotting commands
• Do not default imaginary part to 1 in complex::make (was error prone)
• Optimize the integer power case for range objects
• Zero detection for expressions and polynomials in simplifications
• Makefiles no longer emit confusing mv output in make compare
• New stack_buffer facility in the runtime to keep multiple exansions on stack
• Add ISOL tests for sec, csc, cot functions
• Consolidate project guidance into AGENTS.md
• Simplify simulator beep control logic: -N blocks beeps, -n restores them
• Refresh implementation status
• Update documentation for PGDIR, STO and RCL new capabilties
• Internal facility to swap arbitrary stack levels
• Update man page
• Add recorder_scope-compatible instrumentation for GC and available memory
• Accelerate display of constants/equations/library menus

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This discussion was created from the release Release 0.9.20 "Corpus" - Polynomials and algebraic expressions.