GNU Octave Version 7

Summary of important user-visible changes

April 06, 2022

News for version  7   6   5   4.4   4.2   4   3.8   3.6   3.4   3.2   3   2   1   (Release History)

General improvements

  • Many functions in Octave can be called in a command form—no parentheses for invocation and no return argument assignment—or in a functional form—parentheses and ‘=’ for assignment of return values.

    Command Form Example

    mkdir new_directory

    Function Form Example

    status = mkdir ("new_directory")

    Octave now handles errors that occur in a consistent manner. If called in command form and there is a failure, an error is thrown and a message printed. If called in functional form, no error or message is printed and the failure is communicated to the programmer via the output status variable.

    The following list of functions have been modified.

    • copyfile
    • fcntl
    • fileattrib
    • kill
    • link
    • mkfifo
    • movefile
    • rename
    • rmdir
    • symlink
    • unlink
  • Calling a user-defined function with too many inputs or outputs is now an error. The interpreter makes this check automatically. If a function uses varargin then the check is skipped for function inputs, and if a function uses varargout then the check is skipped for function outputs. Input validation for functions typically begins with checking that the number of inputs and outputs match expectations. Existing code can be simplified by removing these checks which are now done by the interpreter. Typically, code blocks like the following can simply be deleted.

    ## Checking number of inputs
    if (nargin > 2)
      print_usage ();
    ## Checking number of outputs
    if (nargout > 1)
      print_usage ();
  • Binary and hexadecimal constants like 0b101 and 0xDEADBEEF now create integers (unsigned by default) with sizes determined from the number of digits present. For example, 0xff creates a uint8 value and 0xDEADBEEF creates a uint64 value. You may also use a suffix of the form u8, u16, u32, u64, s8, s16, s32, or s64 to explicitly specify the data type to use (u or s to indicate unsigned or signed and the number to indicate the integer size).

    Binary constants are limited to 64 binary digits and hexadecimal constants are limited to 16 hexadecimal digits with no automatic rounding or conversion to floating point values. Note that this may cause problems in existing code. For example, an expression like [0x1; 0x100; 0x10000] will be uint8 (because of the rules of concatenating integers of different sizes) with the larger values truncated (because of the saturation semantics of integer values). To avoid these kinds of problems either: 1) declare the first integer to be of the desired size such as [0x1u32; 0x100; 0x10000], or 2) pad constants in array expressions with leading zeros so that they use the same number of digits for each value such as [0x00_00_01; 0x00_01_00; 0x01_00_00].

  • The colon operator now works for integer (int8, int16, …, uint64) and single data types. However, only double ranges use a memory-efficient storage scheme internally. Other data types are stored as ordinary arrays.

  • The increment and decrement operators ++ and -- must “hug” their corresponding variables. In previous versions of Octave, whitespaces between these operators and the variable they affect were allowed. That is no longer the case.

  • The mldivide function (i.e., the \ operator) now uses an LU decomposition to solve nearly singular full square matrices. This is Matlab-compatible and yields results which more nearly minimize norm (A*x - b). Previously, Octave computed a minimum-norm solution.

  • The factor function has been overhauled for speed. For large inputs > 1e14, it can be up to 10,000 times faster.

  • The isprime function uses a new primality testing algorithm that is up to 50,000 times faster for inputs > 1e14.

  • The betainc function now calculates an exact output for the important special cases where a or b are 1.

  • The whos function now displays an additional attribute ‘s’ when the variable is a sparse type.

  • As part of GSoC 2020, Abdallah K. Elshamy implemented the jsondecode and jsonencode functions to read and write JSON data.

  • As part of GSoC 2021, Abdallah K. Elshamy implemented the jupyter_notebook classdef class. This class supports running and filling Jupyter Notebooks using the Octave language kernel from Octave itself. Making the evaluation of long-running Jupyter Notebooks on a computing server without permanent browser connection possible.

  • By default, the history file is now located at $DATA/octave/history, where $DATA is a platform dependent location for (roaming) user data files (e.g., ${XDG_DATA_HOME} or, if that is not set, ~/.local/share on Unix-like operating systems or %APPDATA% on Windows).

  • For Octave on Windows OS, the minimum required version of the Windows API is now 6.1 (Windows 7 or newer).

  • The non-re-entrant version of the QHull library “libqhull” was deprecated upstream. Octave now (optionally) requires the re-entrant version of that library “libqhull_r” instead.

  • Octave’s build system no longer appends “++” to the end of the “magick++” library name (set with the --with-magick= configure flag). The real name of the “magick++” library (including any potentially trailing “++”) needs to be set in that option now.

  • The pkg update command now accepts options that are passed to pkg install for each updated package. Specifying -local or -global will restrict update checks to local or global installed packages, respectively.

Graphical User Interface

  • The graphical user interface is now available in Hungarian and Turkish.

  • In debug mode, symbol values are now shown in tooltips when hovering variables in the editor panel.

  • The “Disable global shortcuts when Command Window has focus” GUI preference under the Shortcuts tab is now disabled by default. This option disables keyboard shortcuts to avoid interference with readline key strokes in the Command Window. Unlike versions prior to Octave 7, this preference now also affects the Ctrl-C/V shortcuts for copy/paste.

  • In command line mode, i.e. when Octave is started without the --gui option, the doc command now opens the GUI documentation browser as a standalone widget, provided that Octave was compiled with GUI support.

Graphics backend

  • Support for Qt4 for both graphics and the GUI has been removed.

  • If a working LaTeX tool chain is found on the path, including latex, dvipng, and dvisvgm binaries, then text strings can now be rendered properly when using the "latex" value for the text objects’ "interpreter" property and axes objects’ "ticklabelinterpreter". Type doc "latex interpreter" for further info.

  • The "Marker" property for plot objects now accepts | which draws a vertical line or _ which draws a horizontal line.

  • The FMT format argument for plot commands now accepts long forms for color names which may be more understandable than the existing one-letter codes. For example, the RGB value [0 0 0] can now be specified by "black" in addition to "k".

  • The color graphics properties, for example "EdgeColor" or "FaceColor", now accept HTML specifications. An HTML specification is a string that begins with the character ‘#’ and is followed by either 3 or 6 hexadecimal digits. For example, magenta which is 100% red and blue values can specified by "#FF00FF" or "#F0F".

  • The additional property "contextmenu" has been added to all graphics objects. It is equivalent to the previously used "uicontextmenu" property which is hidden now.

  • uicontrol objects now fully implement the "Off" and "Inactive" values of the "Enable" property. When the value is "Off", no interaction with the object occurs and the uicontrol changes color (typically to gray) to indicate it is disabled. When the value is "Inactive", the object appears normally (no change in color), but it is not possible to change the value of the object (such as modifying text in an Edit box or clicking on a RadioButton).

  • The "ListBoxTop" property for uicontrol objects has been implemented for set commands.

  • The Title property for print formats such as PDF or SVG is now set to the title displayed on the figure window which contains the plot.

  • Additional properties have been added to the axes graphics object:

    • "alphamap" (not yet implemented)
    • "alphascale" (not yet implemented)
    • "colorscale" (not yet implemented)
    • "fontsizemode" (not yet implemented)
    • "innerposition" (equivalent to "position")
    • "interactions" (not yet implemented)
    • "layout" (not yet implemented)
    • "legend" (not yet implemented)
    • "nextseriesindex" (read-only, used by scatter graphics objects)
    • "positionconstraint" (replacement for "activepositionproperty" which is now a hidden property. No plans for removal.)
    • "toolbar" (not yet implemented)
    • "xaxis" (not yet implemented)
    • "yaxis" (not yet implemented)
    • "zaxis" (not yet implemented)

Matlab compatibility

  • The function griddata now implements the "v4" Biharmonic Spline Interpolation method. In adddition, the function now accepts 3-D inputs by passing the data to griddata3.

  • Coordinate transformation functions cart2sph, sph2cart, cart2pol, and pol2cart now accept either row or column vectors for coordinate inputs. A single coordinate matrix with one variable per column can still be used as function input, but a single output variable will now contain just the first output coordinate, and will no longer return the full output coordinate matrix. Output size matches the size of input vectors, or in the case of an input matrix will be column vectors with rows corresponding to the input coordinate matrix.

  • The function dec2bin and dec2hex now support negative numbers.

  • The function factor now supports uint64 inputs larger than flintmax.

  • The function primes now supports char inputs.

  • The functions quantile and prctile now permit operating on dimensions greater than ndims (x).

  • The function iqr now uses Matlab compatible interpolation for quantile values. The dimension input now allows a vector, “all”, and dimensions greater than ndims (x). The function also handles Inf and NaN input values in a Matlab-compatible manner.

  • The function importdata now produces more compatible results when the file contains a 2-D text matrix.

  • The file functions copyfile, mkdir, movefile, rmdir now return a logical value (true/false) rather than a numeric value (1/0).

  • uimenu now accepts property "Text" which is identical to "Label". Matlab recommends using "Text" in new code, although there is no announced date for deprecating "Label".

  • The functions scatter and scatter3 now return a handle to a scatter graphics object. For compatibility, they return an hggroup of patch graphics objects when the "gnuplot" graphics toolkit is used. In previous versions of Octave, these functions returned an hggroup of patch graphics objects for all graphics toolkits.

  • The functions bar and barh now handle stacked negative bar values in a Matlab-compatible manner. Negative values now stack below the zero axis independently of a positive value bars in the same stack. Previously the negative bars could overlap positive bars depending on drawing order.

  • The functions bar and barh now use colors from the "ColorOrder" axes property rather than the "Colormap" figure property unless one of the histogram options (@qcode{“hist”}, @qcode{“histc”} was specified.

  • The function saveas now defaults to saving in Octave figure format (.ofig) rather than PDF (.pdf).

  • A new warning ID ("Octave:unimplemented-matlab-functionality") has been added which prints a warning when Octave’s parser recognizes valid Matlab code, but for which Octave does not yet implement the functionality. By default, this warning is enabled.

  • When Octave is started with the --traditional option for maximum compatibility the print_struct_array_contents internal variable is set to true.

  • The function repelem now produces a row vector output when the input is a scalar.

  • The functions var and std now accept a weight vector as input and compute the weigthed variance. Dimension input now allows a vector and the keyword “all”.

Deprecated functions and operators

The following functions and operators have been deprecated in Octave 7 and will be removed from Octave 9 (or whatever version is the second major release after 7):

  • Functions

    Function Replacement
    disable_diagonal_matrix optimize_diagonal_matrix
    disable_permutation_matrix optimize_permutation_matrix
    disable_range optimize_range
  • Operators

    Operator Replacement Description
    ** ^ Matrix exponent
    .** .^ Element-by-element exponent
    .+ + Element-by-element addition
    .- - Element-by-element subtraction
  • Interpreter

    • The use of '...' for line continuations inside double-quoted strings has been deprecated. Use '\' for line continuations inside strings instead.

    • The use of '\' as a line continuation outside of double-quoted strings has been deprecated. Use '...' for line continuations instead.

    • Any trailing whitespace after a '\' line continuation has been deprecated. Delete unnecessary trailing whitespace.

The following functions were deprecated in Octave 6 and will be removed from Octave 8 (or whatever version is the second major release after 6):

  • Functions

    Function Replacement
    runtests oruntests
  • The environment variable used by mkoctfile for linker flags is now LDFLAGS rather than LFLAGS. LFLAGS was deprecated in Octave 6, and a warning is now emitted if it is used, but it will continue to work.

Removed functions, properties, and features

The following functions and properties were deprecated in Octave 5 and have been removed from Octave 7.

  • Functions

    Function Replacement
    output_max_field_width output_precision
    is_keyword iskeyword
  • Properties

    Object Property Value
    text fontangle "oblique"
    uibuttongroup fontangle "oblique"
    uicontrol fontangle "oblique"
    uipanel fontangle "oblique"
    uitable fontangle "oblique"
  • The prototype JIT compiler has been removed from Octave. Since it was first added as part of a Google Summer of Code project in 2012, no one has ever seriously taken on further development of it and it still does nothing significant. It is out of date with the default interpreter that walks the parse tree. Even though we have fixed the configure script to disable it by default, people still ask questions about how to build it, but it doesn’t seem that they are doing that to work on it but because they think it will make Octave code run faster (it never did, except for some extremely simple bits of code as examples for demonstration purposes only). The following functions related to the JIT compiler have also been removed: debug_jit, jit_enable, jit_failcnt, and jit_startcnt.

Alphabetical list of new functions added in Octave 7

  • cospi
  • getpixelposition
  • endsWith
  • fill3
  • jsondecode
  • jsonencode
  • jupyter_notebook
  • listfonts
  • memory
  • ordqz
  • rng
  • sinpi
  • startsWith
  • streamribbon
  • turbo
  • uniquetol
  • xtickangle
  • ytickangle
  • ztickangle