News for Octave Version 2

Summary of changes for version 2.0.17

This will probably be the last release in the 2.0.x series. There are a few bug fixes, but the major change is to print a message saying that Octave 2.0.x cannot be compiled with gcc 3.0.x or gcc 2.96. If you want to build Octave 2.0.x, you will need to use gcc 2.95.x. If you want to use gcc 3.0.x or some later version, you should be using the Octave 2.1.35 sources or a more recent version.

Summary of changes for version 2.0.16

This is primarily a bug-fixing release.

Summary of changes for version 2.0.15

This is primarily a bug-fixing release.

If you are using GNU Emacs 19.34 or earlier, you will need to add the following code to your ~/.emacs file in order to use Emacs Octave mode:

      ;; Set up the custom library.
      ;; taken from http://www.dina.kvl.dk/~abraham/custom/
      (eval-and-compile
	(condition-case ()
	    (require 'custom)
	  (error nil))
	(if (and (featurep 'custom) (fboundp 'custom-declare-variable))
	    nil ;; We've got what we needed
	  ;; We have the old custom-library, hack around it!
	  (defmacro defgroup (&rest args)
	    nil)
	  (defmacro defcustom (var value doc &rest args) 
	    (` (defvar (, var) (, value) (, doc))))))

Summary of changes for version 2.0.14

This release fixes numerous bugs and adds the following new features:

argv is now padded with blanks instead of ASCII NUL.
New functions:

besselh
Hankel functions of the first and second kind
airy
Airy functions of the first and second kind, and their derivatives
The Bessel functions now accept complex values for the argument and any real value for the order.
The value of LOADPATH set by the environment variable OCTAVE_PATH, the -p or --path command line options, or on the command line is no longer modified to include the default path. Instead it is left as specified. Its default value is now ":", which tells Octave to search the default path, and the new built-in variable DEFAULT_LOADPATH contains the default list of directories to search.
The function file_in_path no longer does any special processing of its PATH argument. To search LOADPATH for files, it is now generally better to use the new function file_in_loadpath.
If fread is given a skip parameter, the skip is performed after the read instead of before (for compatibility with Matlab).
The new built-in variable `crash_dumps_octave_core' controls whether Octave writes user variables to the file `octave-core' when it crashes or is killed by a signal. The default value is 1 (0 if you use --traditional).
If LOADPATH contains a doubled colon, the default path is inserted in its place. This is similar to the substitution that also takes place for leading or trailing colons in the LOADPATH.
Loops of the form `for i = STRING ... endfor' are now allowed.
It is now possible to set the iteration limit for lsode using lsode_options ("step limit", N).
New functions:

is_complex
tell whether a value is complex
isnumeric
tell whether a value is a numeric object
isfinite
find finite elements of a matrix object
rehash
re-initialize the cache of directories in LOADPATH
graw
send a string to the gnuplot subprocess
New functions from Kurt Hornik's Octave-ci package:
- In finance (new directory):
  
  fv
  
  future value of an investment
  
  fvl
  
  future value of an initial lump sum investment
  
  irr
  
  internal rate of return of an investment
  
  nper
  
  number of payments needed for amortizing a loan
  
  npv
  
  net present value of a series of payments
  
  pmt
  
  amount of periodic payment needed to amortize a loan
  
  pv
  
  present value of an investment
  
  pvl
  
  present value of an investment that pays off at the end
  
  rate
  
  rate of return of an investment
  
  vol
  
  volatility of financial time series data
- In linear-algebra:
  
  dmult
  
  rescale the rows of a matrix
- In signal:
  
  arch_fit
  
  fit an ARCH regression model
  
  arch_rnd
  
  simulate an ARCH process
  
  arch_test
  
  test for conditional heteroscedascity
  
  arma_rnd
  
  simulate an ARMA process
  
  autocor
  
  compute autocorrelations
  
  autocov
  
  compute autocovariances
  
  autoreg_matrix
  
  design matrix for autoregressions
  
  bartlett
  
  coefficients of the Bartlett (triangular) window
  
  blackman
  
  coefficients of the Blackman window
  
  diffpara
  
  estimate the fractional differencing parameter
  
  durbinlevinson
  
  perform one step of the Durbin-Levinson algorithm
  
  fractdiff
  
  compute fractional differences
  
  hamming
  
  coefficients of the Hamming window
  
  hanning
  
  coefficients of the Hanning window
  
  hurst
  
  estimate the Hurst parameter
  
  periodogram
  
  compute the periodogram
  
  rectangle_lw
  
  rectangular lag window
  
  rectangle_sw
  
  rectangular spectral window
  
  sinetone
  
  compute a sine tone
  
  sinewave
  
  compute a sine wave
  
  spectral_adf
  
  spectral density estimation
  
  spectral_xdf
  
  spectral density estimation
  
  spencer
  
  apply Spencer's 15-point MA filter
  
  stft
  
  short-term Fourier transform
  
  synthesis
  
  recover a signal from its short-term Fourier transform
  
  triangle_lw
  
  triangular lag window
  
  triangle_sw
  
  triangular spectral window
  
  yulewalker
  
  fit AR model by Yule-Walker method
- In statistics/base (new directory):
  
  center
  
  center by subtracting means
  
  cloglog
  
  complementary log-log function
  
  cor
  
  compute correlations
  
  cov
  
  compute covariances
  
  cut
  
  cut data into intervals
  
  iqr
  
  interquartile range
  
  kendall
  
  kendall's rank correlation tau
  
  logit
  
  logit transformation
  
  mean
  
  compute arithmetic, geometric, and harmonic mean
  
  meansq
  
  compute mean square
  
  moment
  
  compute moments
  
  ppplot
  
  perform a PP-plot (probability plot)
  
  probit
  
  probit transformation
  
  qqplot
  
  perform a QQ-plot (quantile plot)
  
  range
  
  compute range
  
  ranks
  
  compute ranks
  
  run_count
  
  count upward runs
  
  spearman
  
  spearman's rank correlation rho
  
  statistics
  
  compute basic statistics
  
  studentize
  
  subtract mean and divide by standard deviation
  
  table
  
  cross tabulation
  
  values
  
  extract unique elements
  
  var
  
  compute variance
- In statistics/distributions (new directory):
  
  beta_cdf
  
  CDF of the Beta distribution
  
  beta_inv
  
  Quantile function of the Beta distribution
  
  beta_pdf
  
  PDF of the Beta distribution
  
  beta_rnd
  
  Random deviates from the Beta distribution
  
  binomial_cdf
  
  CDF of the binomial distribution
  
  binomial_inv
  
  Quantile function of the binomial distribution
  
  binomial_pdf
  
  PDF of the binomial distribution
  
  binomial_rnd
  
  Random deviates from the binomial distribution
  
  cauchy_cdf
  
  CDF of the Cauchy distribution
  
  cauchy_inv
  
  Quantile function of the Cauchy distribution
  
  cauchy_pdf
  
  PDF of the Cauchy distribution
  
  cauchy_rnd
  
  Random deviates from the Cauchy distribution
  
  chisquare_cdf
  
  CDF of the chi-square distribution
  
  chisquare_inv
  
  Quantile function of the chi-square distribution
  
  chisquare_pdf
  
  PDF of the chi-sqaure distribution
  
  chisquare_rnd
  
  Random deviates from the chi-square distribution
  
  discrete_cdf
  
  CDF of a discrete distribution
  
  discrete_inv
  
  Quantile function of a discrete distribution
  
  discrete_pdf
  
  PDF of a discrete distribution
  
  discrete_rnd
  
  Random deviates from a discrete distribution
  
  empirical_cdf
  
  CDF of the empirical distribution
  
  empirical_inv
  
  Quantile function of the empirical distribution
  
  empirical_pdf
  
  PDF of the empirical distribution
  
  empirical_rnd
  
  Bootstrap samples from the empirical distribution
  
  exponential_cdf
  
  CDF of the exponential distribution
  
  exponential_inv
  
  Quantile function of the exponential distribution
  
  exponential_pdf
  
  PDF of the exponential distribution
  
  exponential_rnd
  
  Random deviates from the exponential distribution
  
  f_cdf
  
  CDF of the F distribution
  
  f_inv
  
  Quantile function of the F distribution
  
  f_pdf
  
  PDF of the F distribution
  
  f_rnd
  
  Random deviates from the F distribution
  
  gamma_cdf
  
  CDF of the Gamma distribution
  
  gamma_inv
  
  Quantile function of the Gamma distribution
  
  gamma_pdf
  
  PDF of the Gamma distribution
  
  gamma_rnd
  
  Random deviates from the Gamma distribution
  
  geometric_cdf
  
  CDF of the geometric distribution
  
  geometric_inv
  
  Quantile function of the geometric distribution
  
  geometric_pdf
  
  PDF of the geometric distribution
  
  geometric_rnd
  
  Random deviates from the geometric distribution
  
  hypergeometric_cdf
  
  CDF of the hypergeometric distribution
  
  hypergeometric_inv
  
  Random deviates from hypergeometric distribution
  
  hypergeometric_pdf
  
  PDF of the hypergeometric distribution
  
  hypergeometric_rnd
  
  Random deviates from hypergeometric distribution
  
  kolmogorov_smirnov_cdf
  
  CDF of the Kolmogorov-Smirnov distribution
  
  laplace_cdf
  
  CDF of the Laplace distribution
  
  laplace_inv
  
  Quantile function of the Laplace distribution
  
  laplace_pdf
  
  PDF of the Laplace distribution
  
  laplace_rnd
  
  Random deviates from the Laplace distribution
  
  logistic_cdf
  
  CDF of the logistic distribution
  
  logistic_inv
  
  Quantile function of the logistic distribution
  
  logistic_pdf
  
  PDF of the logistic distribution
  
  logistic_rnd
  
  Random deviates from the logistic distribution
  
  lognormal_cdf
  
  CDF of the log normal distribution
  
  lognormal_inv
  
  Quantile function of the log normal distribution
  
  lognormal_pdf
  
  PDF of the log normal distribution
  
  lognormal_rnd
  
  Random deviates from the log normal distribution
  
  normal_cdf
  
  CDF of the normal distribution
  
  normal_inv
  
  Quantile function of the normal distribution
  
  normal_pdf
  
  PDF of the normal distribution
  
  normal_rnd
  
  Random deviates from the normal distribution
  
  pascal_cdf
  
  CDF of the Pascal (negative binomial) distribution
  
  pascal_inv
  
  Quantile function of the Pascal distribution
  
  pascal_pdf
  
  PDF of the Pascal (negative binomial) distribution
  
  pascal_rnd
  
  Random deviates from the Pascal distribution
  
  poisson_cdf
  
  CDF of the Poisson distribution
  
  poisson_inv
  
  Quantile function of the Poisson distribution
  
  poisson_pdf
  
  PDF of the Poisson distribution
  
  poisson_rnd
  
  Random deviates from the Poisson distribution
  
  stdnormal_cdf
  
  CDF of the standard normal distribution
  
  stdnormal_inv
  
  Quantile function of standard normal distribution
  
  stdnormal_pdf
  
  PDF of the standard normal distribution
  
  stdnormal_rnd
  
  Random deviates from standard normal distribution
  
  t_cdf
  
  CDF of the t distribution
  
  t_inv
  
  Quantile function of the t distribution
  
  t_pdf
  
  PDF of the t distribution
  
  t_rnd
  
  Random deviates from the t distribution
  
  uniform_cdf
  
  CDF of the uniform distribution
  
  uniform_inv
  
  Quantile function of the uniform distribution
  
  uniform_pdf
  
  PDF of the uniform distribution
  
  uniform_rnd
  
  Random deviates from the uniform distribution
  
  weibull_cdf
  
  CDF of the Weibull distribution
  
  weibull_inv
  
  Quantile function of the Weibull distribution
  
  weibull_pdf
  
  PDF of the Weibull distribution
  
  weibull_rnd
  
  Random deviates from the Weibull distribution
  
  wiener_rnd
  
  Simulate a Wiener process
- In statistics/models (new directory):
  
  logistic_regression
  
  ordinal logistic regression
  
  logistic_regression_derivatives
  
  derivates of log-likelihood in logistic regression
  
  logistic_regression_likelihood
  
  likelihood in logistic regression
- In statistics/tests (new directory):
  
  anova
  
  one-way analysis of variance
  
  bartlett_test
  
  bartlett test for homogeneity of variances
  
  chisquare_test_homogeneity
  
  chi-square test for homogeneity
  
  chisquare_test_independence
  
  chi-square test for independence
  
  cor_test
  
  test for zero correlation
  
  f_test_regression
  
  test linear hypotheses in linear regression model
  
  hotelling_test
  
  test for mean of a multivariate normal
  
  hotelling_test_2
  
  compare means of two multivariate normals
  
  kolmogorov_smirnov_test
  
  one-sample Kolmogorov-Smirnov test
  
  kolmogorov_smirnov_test_2
  
  two-sample Kolmogorov-Smirnov test
  
  kruskal_wallis_test
  
  kruskal-Wallis test
  
  manova
  
  one-way multivariate analysis of variance
  
  mcnemar_test
  
  mcnemar's test for symmetry
  
  prop_test_2
  
  compare two proportions
  
  run_test
  
  run test for independence
  
  sign_test
  
  sign test
  
  t_test
  
  student's one-sample t test
  
  t_test_2
  
  student's two-sample t test
  
  t_test_regression
  
  test one linear hypothesis in linear regression model
  
  u_test
  
  mann-Whitney U-test
  
  var_test
  
  f test to compare two variances
  
  welch_test
  
  welch two-sample t test
  
  wilcoxon_test
  
  wilcoxon signed-rank test
  
  z_test
  
  test for mean of a normal sample with known variance
  
  z_test_2
  
  compare means of two normal samples with known variances
The save command now accepts the option -append to save the variables at the end of the file, leaving the existing contents.
New command-line option --no-history (also available using the single character option -H) inhibits saving command history.
The mkoctfile script now accepts -DDEF options and passes them on to the C and C++ compilers.

Summary of changes for version 2.0.13

This is a bug-fixing release. There are no new user-visible features.

Summary of changes for version 2.0.12

Tilde expansion is once again performed on the directories listed in the LOADPATH variable.
gplot now supports the `axes' qualifier that is new with gnuplot 3.6beta.
Timestamps on .m and .oct files are now only checked if a prompt has been printed since the last timestamp check.
Octave now prints a warning if a .m or .oct file has a time stamp in the future.
For matrices, x(:) now works no matter what the value of do_fortran_indexing is.
New keywords __FILE__ and __LINE__ expand to the name of the file that is being read and the current input line number, respectively.
The GNU Info reader is no longer distributed with Octave because current releases of GNU Info now support all the features needed by Octave. If your copy of GNU Info doesn't support the --index-search option, you should install a newer version of GNU Info, which is distributed as part of the GNU Texinfo package.
Running `make check' should work now before you run `make install', even if you build a copy of Octave that depends on shared versions of the Octave libraries.
Octave now uses kpathsea 3.2.
The new built-in variable `kluge_procbuf_delay' specifies the number of microseconds to delay in the parent process after forking. By default on gnu-win32 systems, it's set to 500000 (1/2 second). On other systems, the default value is 0. Delaying for a short time in the parent after forking seems to avoid problems in which communicating with subprocesses via pipes would sometimes cause Octave to hang. I doubt that the delay is really the right solution. If anyone has a better idea, I'd love to hear it.

Summary of changes for version 2.0.11

There are two new built-in variables that control how global variables are initialized. If `initialize_global_variables' is nonzero, global variables are initialized to the value of the variable `default_global_variable_value'. The default value of `initialize_global_variables' is 0 (1 if you use --traditional) and `default_global_variable_value' is undefined (the empty matrix if you use --traditional). The default settings are compatible with versions of Octave before 2.0.10.

Summary of changes for version 2.0.10

The built-in variable `PWD' has been removed. If you need to get the value of the current working directory, use the pwd() function instead.
For compatibility with Matlab, Octave's lyap function now solves
```
      A*X + X*A' + C = 0
```
instead of
```
      A'*X + X*A + C = 0
```
To try to avoid confusion for people who are used to the way Octave behaved in previous versions, a warning is printed the first time lyap is called in a given session. To completely disable the warning, simply add
```
      global __disable_lyap_interface_change_warning__;
```
to your ~/.octaverc file. The warning will eventually disappear for good in some future version of Octave.
New built-in functions for computing Bessel functions: besseli, besselj, besselk, and bessely.
The gammai and betai functions are now implemented as built-in functions rather than function files.
The new built-in variable `implicit_num_to_str_ok' controls whether Octave converts expressions like `[97, 98, 99, "123"]' to strings. The default value is 0 unless you use --traditional.
The new built-in variable `fixed_point_format' controls whether Octave uses a scaled fixed-point format for displaying matrices. The default value is 0 unless you use --traditional.
The function sumsq now computes sum (x .* conj (x)) for complex values.
Dynamically linked functions can be cleared.
If a .oct file has a time stamp more recent than the time that it was loaded, it is automatically reloaded. Reloading a .oct file may cause several functions to be cleared automatically. By default, a warning is printed that lists the names of the functions that will be cleared. You can suppress the message by setting the new built-in variable `warn_reload_forces_clear' to 0.
Global variables are now initialized to the empty matrix, for compatibility with Matlab.
Explicit initialization of global variables only happens once. For example, after the following statements are evaluated, g still has the value 1.
```
      global g = 1
      global g = 2
```
This is useful for initializing global variables that are used to maintain state information that is shared among several functions.
The new built-in variable max_recursion_depth allows you to prevent Octave from attempting infinite recursion. The default value is 256.
Octave now uses readline version 2.1 and kpathsea 3.0.
The libreadline and libkpathsea libraries are no longer installed.
The libcruft, liboctave, and liboctinterp libraries are now installed in $libdir/octave instead of just $libdir.
It's no longer necessary to have libg++, but you do need to have the GNU implementation of libstdc++. If you are using gcc 2.7.2, libstdc++ is distributed as part of libg++ 2.7.2. For later versions, libstdc++ is distributed separately. For egcs, libstdc++ is included with the compiler distribution.

Summary of changes for version 2.0.9

This is a bug-fixing release, but there is one new user-visible feature:

It is now possible to specify a label for lines in the plot key when using the plot function. For example,
```
      plot (x, y, "-*;sin(x);")
```
plots y vs. x using the linespoints style and sets the title of the line in the key to be `sin(x)'

Summary of changes for version 2.0.8

This is a bug-fixing release. There are only a few new user-visible features.

If the argument to eig() is symmetric, Octave uses the specialized Lapack subroutine for symmetric matrices for a significant increase in performance.
It is now possible to use the mkoctfile script to create .oct files from multiple source and object files.

Summary of changes for version 2.0.7

This is a bug-fixing release. There are no new user-visible features.

Summary of changes for version 2.0.6

This is primarily a bug-fixing release. There are only a few new user-visilbe features.

The new built-in variable default_eval_print_flag controls whether Octave prints the results of commands executed by eval() that do not end with semicolons. The default is 1.
The new built-in constant OCTAVE_HOME specifies the top-level directory where Octave is installed.
Octave no longer includes functions to work with NPSOL or QPSOL, because they are not free software.

Summary of changes for version 2.0.5

A `switch' statement is now available. See the Statements chapter in the manual for details.
Commands like ls, save, and cd may now also be used as formal parameters for functions.
More tests.

Summary of changes for version 2.0.4

It is now possible to use commands like ls, save, and cd as simple variable names. They still cannot be used as formal parameters for functions, or as the names of structure variables. Failed assignments leave them undefined (you can recover the orginal function definition using clear).
Is is now possible to invoke commands like ls, save, and cd as normal functions (for example, load ("foo", "x", "y", "z")).

Summary of changes for version 2.0.3

The manual has been completely revised and now corresponds much more closely to the features of the current version.
The return value for assignment expressions is now the RHS since that is more consistent with the way other programming languages work. However, Octave still prints the entire LHS value so that
```
      x = zeros (1, 2);
      x(2) = 1
```
still prints
```
      x =

        0  1
```
but an assignment like
```
      z = x(2) = 1
```
sets z to 1 (not [ 0, 1 ] as in previous versions of Octave).
It is now much easier to make binary distributions. See the Binary Distributions section of the manual for more details.

Summary of changes for version 2.0.2

Octave now stops executing commands from a script file if an error is encountered.
The return, and break commands now cause Octave to quit executing commands from script files. When used in invalid contexts, the break, continue, and return commands are now simply ignored instead of producing parse errors.
size ("") is now [0, 0].
New functions:

sleep

pause execution for a specified number of seconds

usleep

pause execution for a specified number of microseconds

Summary of changes for version 2.0.1

Other than bug fixes, there were no user-visible changes in version 2.0.1.

Summary of changes for version 2.0

The set and show commands for setting and displaying gnuplot parameters have been replaced by gset and gshow. This change will probably break lots of things, but it is necessary to allow for compatibility with the Matlab graphics and GUI commands in a future version of Octave. (For now, the old set and show commands do work, but they print an annoying warning message to try to get people to switch to using gset.)
Octave has been mostly ported to Windows NT and Windows 95 using the beta 17 release of the Cygnus GNU-WIN32 tools. Not everything works, but it is usable. See the file README.WINDOWS for more information.
Dynamic linking works on more systems using dlopen() and friends (most modern Unix systems) or shl_load() and friends (HP/UX systems). A simple example is provided in examples/hello.cc. For this feature to work, you must configure Octave with --enable-shared. You may also need to have a shared-library version of libg++ and libstdc++.
New data types can be added to Octave by writing a C++ class. On systems that support dynamic linking, new data types can be added to an already running Octave binary. A simple example appears in the file examples/make_int.cc. Other examples are the standard Octave data types defined in the files src/ov*.{h,cc} and src/op-*.cc.
The configure option --enable-bounds-check turns on bounds checking on element references for Octave's internal array and matrix classes. It's enabled by default. To disable this feature, configure Octave with --disable-bounds-check.
The C-style I/O functions (fopen, fprintf, etc.) have been rewritten to be more compatible with Matlab. The fputs function has also been added. Usage of the *printf functions that was allowed in previous versions of Octave should still work. However, there is no way to make the new versions of the *scanf functions compatible with Matlab *and* previous versions of Octave. An optional argument to the *scanf functions is now available to make them behave in a way that is compatible with previous versions of Octave.
Octave can now read files that contain columns of numbers only, with no header information. The name of the loaded variable is constructed from the file name. Each line in the file must have the same number of elements.
The interface to the pager has changed. The new built-in variable `page_output_immediately' controls when Octave sends output to the pager. If it is nonzero, Octave sends output to the pager as soon as it is available. Otherwise, Octave buffers its output and waits until just before the prompt is printed to flush it to the pager.
Expressions of the form
```
      A(i,j) = x
```
where X is a scalar and the indices i and j define a matrix of elements now work as you would expect rather than giving an error. I am told that this is how Matlab 5.0 will behave when it is released.
Indexing of character strings now works.
The echo command has been implemented.
The document command is now a regular function.
New method for handling errors:
```
      try
        BODY
      catch
        CLEANUP
      end_try_catch
```
Where BODY and CLEANUP are both optional and may contain any Octave expressions or commands. The statements in CLEANUP are only executed if an error occurs in BODY.
No warnings or error messages are printed while BODY is executing. If an error does occur during the execution of BODY, CLEANUP can access the text of the message that would have been printed in the builtin constant __error_text__. This is the same as eval (TRY, CATCH) (which may now also use __error_text__) but it is more efficient since the commands do not need to be parsed each time the TRY and CATCH statements are evaluated.
Octave no longer parses the help command by grabbing everything after the keyword `help' until a newline character is read. To get help for `;' or `,', now, you need to use the command `help semicolon' or `help comma'.
Octave's parser now does some simple constant folding. This means that expressions like 3*i are now evaluated only once, when a function is compiled, and the right hand side of expressions like a = [1,2;3,4] are treated as true matrix constants rather than lists of elements which must be evaluated each time they are needed.
Built-in variables that can take values of "true" and "false" can now also be set to any nonzero scalar value to indicate "true", and 0 to indicate "false".
New built-in variables `history_file', `history_size', and `saving_history'.
New built-in variable `string_fill_char' specifies the character to fill with when creating arrays of strings.
If the new built-in variable `gnuplot_has_frames' is nonzero, Octave assumes that your copy of gnuplot includes support for multiple plot windows when using X11. If the new built-in variable `gnuplot_has_multiplot' is nonzero, Octave assumes that your copy of gnuplot has the multiplot support that is included in recent 3.6beta releases. The initial values of these variables are determined by configure, but can be changed in your startup script or at the command line in case configure got it wrong, or if you upgrade your gnuplot installation.
The new plot function `figure' allows multiple plot windows when using newer versions of gnuplot with X11.
Octave now notices when the plotter has exited unexpectedly.
New built-in variable `warn_missing_semicolon'. If nonzero, Octave will warn when statements in function definitions don't end in semicolons. The default value is 0.
Octave now attempts to continue after floating point exceptions or out-of-memory errors.
If Octave crashes, it now attempts to save all user-defined variables in a file named `octave-core' in the current directory before exiting.
It is now possible to get the values of individual option settings for the dassl, fsolve, lsode, npsol, qpsol, and quad functions using commands like
```
      dassl_reltol = dassl_options ("relative tolerance");
```
The svd() function no longer computes the left and right singular matrices unnecessarily. This can significantly improve performance for large matrices if you are just looking for the singular values.
The filter() function is now a built-in function.
New function randn() returns a pseudo-random number from a normal distribution. The rand() and randn() functions have separate seeds and generators.
Octave's command-line arguments are now available in the built-in variable `argv'. The program name is also available in the variables `program_invocation_name' and `program_name'. If executing a script from the command line (e.g., octave foo.m) or using the `#! /bin/octave' hack, the program name is set to the name of the script.
New built-in variable `completion_append_char' used as the character to append to successful command-line completion attempts. The default is " " (a single space).
Octave now uses a modified copy of the readline library from version 1.14.5 of GNU bash.
In prompt strings, `\H' expands to the whole host name.
New built-in variable `beep_on_error'. If nonzero, Octave will try to ring your terminal's bell before printing an error message. The default value is 0.
For functions defined from files, the type command now prints the text of the file. You can still get the text reconstructed from the parse tree by using the new option -t (-transformed).

New command-line argument --traditional sets the following preference variables for compatibility with Matlab:

      PS1                           = ">> "
      PS2                           = ""
      beep_on_error                 = 1
      default_save_format           = "mat-binary"
      define_all_return_values      = 1
      do_fortran_indexing           = 1
      empty_list_elements_ok        = 1
      implicit_str_to_num_ok        = 1
      ok_to_lose_imaginary_part     = 1
      page_screen_output            = 0
      prefer_column_vectors         = 0
      prefer_zero_one_indexing      = 1
      print_empty_dimensions        = 0
      treat_neg_dim_as_zero         = 1
      warn_function_name_clash      = 0
      whitespace_in_literal_matrix  = "traditional"

New functions:

readdir

returns names of files in directory as array of strings

mkdir

create a directory

rmdir

remove a directory

rename

rename a file

unlink

delete a file

umask

set permission mask for file creation

stat

get information about a file

lstat

get information about a symbolic link

glob

perform filename globbing

fnmatch

match strings with filename globbing patterns

more

turn the pager on or off

gammaln

alias for lgamma
New audio functions from Andreas Weingessel:

lin2mu

linear to mu-law encoding

loadaudio

load an audio file to a vector

mu2lin

mu-law to linear encoding

playaudio

play an audio file

record

record sound and store in vector

saveaudio

save a vector as an audio file

setaudio

executes mixer shell command
New plotting functions from Vinayak Dutt. Ones dealing with multiple plots on one page require features from gnuplot 3.6beta (or later).

bottom_title

put title at the bottom of the plot

mplot

multiplot version of plot

multiplot

switch multiple-plot mode on or off

oneplot

return to one plot per page

plot_border

put a border around plots

subplot

position multiple plots on a single page

subwindow

set subwindow position for next plot

top_title

put title at the top of the plot

zlabel

put a label on the z-axis
New string functions

bin2dec

convert a string of ones and zeros to an integer

blanks

create a string of blanks

deblank

delete trailing blanks

dec2bin

convert an integer to a string of ones and zeros

dec2hex

convert an integer to a hexadecimal string

findstr

locate occurrences of one string in another

hex2dec

convert a hexadecimal string to an integer

index

return position of first occurrence a string in another

rindex

return position of last occurrence a string in another

split

divide one string into pieces separated by another

str2mat

create a string matrix from a list of strings

strrep

replace substrings in a string

substr

extract a substring

The following functions return a matrix of ones and zeros. Elements that are nonzero indicate that the condition was true for the corresponding character in the string array.

isalnum

letter or a digit

isalpha

letter

isascii

ascii

iscntrl

control character

isdigit

digit

isgraph

printable (but not space character)

islower

lower case

isprint

printable (including space character)

ispunct

punctuation

isspace

whitespace

isupper

upper case

isxdigit

hexadecimal digit

These functions return new strings.

tolower

convert to lower case

toupper

convert to upper case
New function, fgetl. Both fgetl and fgets accept an optional second argument that specifies a maximum number of characters to read, and the function fgets is now compatible with Matlab.
Printing in hexadecimal format now works (format hex). It is also possible to print the internal bit representation of a value (format bit). Note that these formats are only implemented for numeric values.
Additional structure features:
- Name completion now works for structures.
- Values and names of structure elements are now printed by default. The new built-in variable `struct_levels_to_print' controls the depth of nested structures to print. The default value is 2.
- New functions:
  
  struct_contains (S, NAME)
  
  returns 1 if S is a structure with element NAME; otherwise returns 0.
  
  struct_elements (S)
  
  returns the names of all elements of structure S in an array of strings.
New io/subprocess functions:

fputs

write a string to a file with no formatting

popen2

start a subprocess with 2-way communication

mkfifo

create a FIFO special file

popen

open a pipe to a subprocess

pclose

close a pipe from a subprocess

waitpid

check the status of or wait for subprocesses
New time functions:

asctime

format time structure according to local format

ctime

equivalent to `asctime (localtime (TMSTRUCT))'

gmtime

return time structure corresponding to UTC

localtime

return time structure corresponding to local time zone

strftime

print given time structure using specified format

time

return current time

The `clock' and `date' functions are now implemented in M-files using these basic functions.
Access to additional Unix system calls:

dup2

duplicate a file descriptor

exec

replace current process with a new process

fcntl

control open file descriptors

fork

create a copy of the current process

getpgrp

return the process group id of the current process

getpid

return the process id of the current process

getppid

return the process id of the parent process

getuid

return the real user id of the current process

getgid

return the real group id of the current process

geteuid

return the effective user id of the current process

getegid

return the effective group id of the current process

pipe

create an interprocess channel
Other new functions:

commutation_matrix

compute special matrix form

duplication_matrix

compute special matrix form

common_size.m

bring arguments to a common size

completion_matches

perform command completion on string

tilde_expand

perform tilde expansion on string

meshgrid

compatible with Matlab's meshgrid function

tmpnam

replaces octave_tmp_file_name

atexit

register functions to be called when Octave exits

putenv

define an environment variable

bincoeff

compute binomial coefficients

nextpow2

compute the next power of 2 greater than a number

detrend

remove a best fit polynomial from data

erfinv

inverse error function

shift

perform a circular shift on the elements of a matrix

pow2

compute 2 .^ x

log2

compute base 2 logarithms

diff

compute differences of matrix elements

vech

stack columns of a matrix below the diagonal

vec

stack columns of a matrix to form a vector

xor

compute exclusive or
Functions for getting info from the password database on Unix systems:

getpwent

read entry from password-file stream, opening if necessary

getpwuid

search for password entry with matching user ID

getpwnam

search for password entry with matching username

setpwent

rewind the password-file stream

endpwent

close the password-file stream
Functions for getting info from the group database on Unix systems:

getgrent

read entry from group-file stream, opening if necessary

getgrgid

search for group entry with matching group ID

getgrnam

search for group entry with matching group name

setgrent

rewind the pgroup-file stream

endgrent

close the group-file stream
The New function octave_config_info returns a structure containing information about how Octave was configured and compiled.
New function getrusage returns a structure containing system resource usage statistics. The `cputime' function is now defined in an M-file using getrusage.
The info reader is now a separate binary that runs as a subprocess. You still need the info reader distributed with Octave though, because there are some new command-line arguments that are not yet available in the public release of Info.
There is a new built-in variable, INFO_PROGRAM, which is used as the name of the info program to run. Its initial value is $OCTAVE_HOME/lib/octave/VERSION/exec/ARCH/info, but that value can be overridden by the environment variable OCTAVE_INFO_PROGRAM, or the command line argument --info-program NAME, or by setting the value of INFO_PROGRAM in a startup script.
There is a new built-in variable, EXEC_PATH, which is used as the list of directories to search when executing subprograms. Its initial value is taken from the environment variable OCTAVE_EXEC_PATH (if it exists) or PATH, but that value can be overridden by the the command line argument --exec-path PATH, or by setting the value of EXEC_PATH in a startup script. If the EXEC_PATH begins (ends) with a colon, the directories $OCTAVE_HOME/lib/octave/VERSION/exec/ARCH and $OCTAVE_HOME/bin are prepended (appended) to EXEC_PATH (if you don't specify a value for EXEC_PATH explicitly, these special directories are prepended to your PATH).
If it is present, Octave will now use an `ls-R' database file to speed up recursive path searching. Octave looks for a file called ls-R in the directory specified by the environment variable OCTAVE_DB_DIR. If that is not set but the environment variable OCTAVE_HOME is set, Octave looks in $OCTAVE_HOME/lib/octave. Otherwise, Octave looks in the directory $datadir/octave (normally /usr/local/lib/octave).
New examples directory.
There is a new script, mkoctfile, that can be used to create .oct files suitable for dynamic linking.
Many more bug fixes.
ChangeLogs are now kept in each subdirectory.