Runtime Environment

`absolute_real_time` () — Function

Returns the number of seconds since midnight, January 1, 1900 GMT. The return value is an integer.

See also elapsed_real_time and elapsed_005frun_005ftime.

Example:

(%i1) absolute_real_time ();
(%o1)                      3385045277
(%i2) 1900 + absolute_real_time () / (365.25 * 24 * 3600);
(%o2)                   2007.265612087104

See also: elapsed_real_time, elapsed_run_time.

`decode_time` (T, tz_offset) — Function

Given the number of seconds (possibly including a fractional part) since midnight, January 1, 1900 GMT, returns the date and time as represented by a list comprising the year, month, day of the month, hours, minutes, seconds, and time zone offset.

tz_offset measures the offset of the time zone, in hours, east (positive) or west (negative) of GMT. tz_offset must be an integer, rational, or float between -24 and 24, inclusive. If tz_offset is not a multiple of 1/3600, it is rounded to the nearest multiple of 1/3600.

If tz_offset is not present, the offset of the local time zone is assumed.

`elapsed_real_time` () — Function

Returns the number of seconds (including fractions of a second) since Maxima was most recently started or restarted. The return value is a floating-point number.

See also absolute_real_time and elapsed_005frun_005ftime.

Example:

(%i1) elapsed_real_time ();
(%o1)                       2.559324
(%i2) expand ((a + b)^500)$
(%i3) elapsed_real_time ();
(%o3)                       7.552087

See also: absolute_real_time, elapsed_run_time.

`elapsed_run_time` () — Function

Returns an estimate of the number of seconds (including fractions of a second) which Maxima has spent in computations since Maxima was most recently started or restarted. The return value is a floating-point number.

See also absolute_real_time and elapsed_005freal_005ftime.

Example:

(%i1) elapsed_run_time ();
(%o1)                         0.04
(%i2) expand ((a + b)^500)$
(%i3) elapsed_run_time ();
(%o3)                         1.26

See also: absolute_real_time, elapsed_real_time.

`encode_time` (year, month, day, hours, minutes, seconds, tz_offset) — Function

Given a time and date specified by year, month, day, hours, minutes, and seconds, encode_time returns the number of seconds (possibly including a fractional part) since midnight, January 1, 1900 GMT.

year must be an integer greater than or equal to 1899. However, 1899 is allowed only if the resulting encoded time is greater than or equal to 0.

month must be an integer from 1 to 12, inclusive.

day must be an integer from 1 to n, inclusive, where n is the number of days in the month specified by month.

hours must be an integer from 0 to 23, inclusive.

minutes must be an integer from 0 to 59, inclusive.

seconds must be an integer, rational, or float greater than or equal to 0 and less than 60. When seconds is not an integer, encode_time returns a rational, such that the fractional part of the return value is equal to the fractional part of seconds. Otherwise, seconds is an integer, and the return value is likewise an integer.

If tz_offset is not present, the offset of the local time zone is assumed.

`maxima_tempdir` — Variable

maxima_tempdir names the directory in which Maxima creates some temporary files. In particular, temporary files for plotting are created in maxima_tempdir.

The initial value of maxima_tempdir is the user’s home directory, if Maxima can locate it; otherwise Maxima makes a guess about a suitable directory.

maxima_tempdir may be assigned a string which names a directory.

`maxima_userdir` — Variable

maxima_userdir names a directory which Maxima searches to find Maxima and Lisp files. (Maxima searches some other directories as well; file_search_maxima and file_search_lisp are the complete lists.)

The initial value of maxima_userdir is a subdirectory of the user’s home directory, if Maxima can locate it; otherwise Maxima makes a guess about a suitable directory.

maxima_userdir may be assigned a string which names a directory. However, assigning to maxima_userdir does not automatically change file_search_maxima and file_search_lisp; those variables must be changed separately.

`parse_timedate` (S) — Function

Parses a string S representing a date or date and time of day and returns the number of seconds since midnight, January 1, 1900 GMT. If there is a nonzero fractional part, the value returned is a rational number, otherwise, it is an integer. parse_timedate returns false if it cannot parse S according to any of the allowed formats.

The string S must have one of the following formats, optionally followed by a timezone designation:

YYYY-MM-DD[ T]hh:mm:ss[,.]nnn

YYYY-MM-DD[ T]hh:mm:ss

YYYY-MM-DD

where the fields are year, month, day, hours, minutes, seconds, and fraction of a second, and square brackets indicate acceptable alternatives. The fraction may contain one or more digits.

Except for the fraction of a second, each field must have exactly the number of digits indicated: four digits for the year, and two for the month, day of the month, hours, minutes, and seconds.

A timezone designation must have one of the following forms:

[+-]hh:mm

[+-]hhmm

[+-]hh

Z

where hh and mm indicate hours and minutes east (+) or west (-) of GMT. The timezone may be from +24 hours (inclusive) to -24 hours (inclusive).

A literal character Z is equivalent to +00:00 and its variants, indicating GMT.

If no timezone is indicated, the time is assumed to be in the local time zone.

Any leading or trailing whitespace (space, tab, newline, and carriage return) is ignored, but any other leading or trailing characters cause parse_timedate to fail and return false.

See also timedate and absolute_005freal_005ftime.

Examples:

Midnight, January 1, 1900, in the local time zone, in each acceptable format. The result is the number of seconds the local time zone is ahead (negative result) or behind (positive result) GMT. In this example, the local time zone is 8 hours behind GMT.

(%i1) parse_timedate ("1900-01-01 00:00:00,000");
(%o1)                         28800
(%i2) parse_timedate ("1900-01-01 00:00:00.000");
(%o2)                         28800
(%i3) parse_timedate ("1900-01-01T00:00:00,000");
(%o3)                         28800
(%i4) parse_timedate ("1900-01-01T00:00:00.000");
(%o4)                         28800
(%i5) parse_timedate ("1900-01-01 00:00:00");
(%o5)                         28800
(%i6) parse_timedate ("1900-01-01T00:00:00");
(%o6)                         28800
(%i7) parse_timedate ("1900-01-01");
(%o7)                         28800

Midnight, January 1, 1900, GMT, in different indicated time zones.

(%i1) parse_timedate ("1900-01-01 19:00:00+19:00");
(%o1)                           0
(%i2) parse_timedate ("1900-01-01 07:00:00+07:00");
(%o2)                           0
(%i3) parse_timedate ("1900-01-01 01:00:00+01:00");
(%o3)                           0
(%i4) parse_timedate ("1900-01-01Z");
(%o4)                           0
(%i5) parse_timedate ("1899-12-31 21:00:00-03:00");
(%o5)                           0
(%i6) parse_timedate ("1899-12-31 13:00:00-11:00");
(%o6)                           0
(%i7) parse_timedate ("1899-12-31 08:00:00-16:00");
(%o7)                           0

See also: timedate, absolute_real_time.

`room` () — Function

Prints out a description of the state of storage and stack management in Maxima. room calls the Lisp function of the same name.

room () prints out a moderate description.

room (true) prints out a verbose description.

room (false) prints out a terse description.

`sstatus` (keyword, item) — Function

When keyword is the symbol feature, item is put on the list of system features. After sstatus (keyword, item) is executed, status (feature, item) returns true. If keyword is the symbol nofeature, item is deleted from the list of system features. This can be useful for package writers, to keep track of what features they have loaded in.

`status` (feature) — Function

Returns information about the presence or absence of certain system-dependent features.

status (feature) returns a list of system features. These include Lisp version, operating system type, etc. The list may vary from one Lisp type to another.

status (feature, item) returns true if item is on the list of items returned by status (feature) and false otherwise. status quotes the argument item. The quote-quote operator '' defeats quotation. A feature whose name contains a special character, such as a hyphen, must be given as a string argument. For example, status (feature, "ansi-cl").

`system` (command, arg_1, …, arg_n) — Function

Executes command as a separate process. The command is passed to the default shell for execution.

system is implemented by a command execution function in the Lisp implementation which compiled Maxima, and therefore the behavior of system varies with the operating system and Lisp implementation. system is known to work on Windows and Linux systems, and might also work on other systems.

All combinations of Lisp implementation and operating system allow command arguments as arg_1, …, arg_n, and some allow command arguments as part of command. SBCL on Windows and Clozure CL on Windows are known to require command arguments to be specified as arg_1, …, arg_n.

system does not attempt to quote or escape spaces or other characters in command or in arg_1, …, arg_n; all arguments are supplied verbatim to the command execution function of the Lisp implementation.

Standard output from command is displayed on the Maxima console by default, and may be captured by with_stdout.

For most Lisp implementations, the call to system returns after command has completed. Job control operations, such as executing a command asynchronously with respect to Maxima, are not known to have the expected effect.

Examples:

system executes command as a separate process. The output of the command dir varies from one system to another.

(%i1) system ("dir", maxima_tempdir);
config-err-UsLLQM
gnome-software-0TNK22
MozillaUpdateLock-6939C585ADF59520
snap-private-tmp
systemd-private-169e359ab2d94b208622fa96dd88c05e-colord.service-ZP9Xn7
(%o1)                           0

All combinations of Lisp implementation and operating system allow command arguments as arg_1, …, arg_n.

(%i1) system ("echo", "Hello", "world", "glad", "to", "meet", "you");
Hello world glad to meet you
(%o1)                           0

Standard output from command is displayed on the Maxima console by default, and may be captured by with_stdout.

(%i1) my_output: sconcat (maxima_tempdir, "/tmp.out");
(%o1)                     /tmp/tmp.out
(%i2) with_stdout (my_output, system ("dir"));
(%o2)                           0
(%i3) S: openr (my_output);
(%o3)               #<FILE-STREAM {7B500975}>
(%i4) readline (S);
(%o4)                      aclocal.m4
(%i5) readline (S);
(%o5)                         admin
(%i6) readline (S);
(%o6)                        archive

For most Lisp implementations, the call to system returns after command has completed. xfontsel is a utility to inspect fonts for the X Windows system; system returns after the user clicks the “quit” button.

(%i1) system ("xfontsel");
(%o1)                           0

`time` (%o1, %o2, %o3, …) — Function

Returns a list of the times, in seconds, taken to compute the output lines %o1, %o2, %o3, … The time returned is Maxima’s estimate of the internal computation time, not the elapsed time. time can only be applied to output line variables; for any other variables, time returns unknown.

Set showtime: true to make Maxima print out the computation time and elapsed time with each output line.

`timedate` (T, tz_offset) — Function

timedate(T, tz_offset) returns a string representing the time T in the time zone tz_offset. The string format is YYYY-MM-DD HH:MM:SS.NNN[+|-]ZZ:ZZ (using as many digits as necessary to represent the fractional part) if T has a nonzero fractional part, or YYYY-MM-DD HH:MM:SS[+|-]ZZ:ZZ if its fractional part is zero.

T measures time, in seconds, since midnight, January 1, 1900, in the GMT time zone.

timedate(T) is equivalent to timedate(T, tz_offset) with tz_offset equal to the offset of the local time zone.

timedate() is equivalent to timedate(absolute_real_time()). That is, it returns the current time in the local time zone.

Example:

timedate with no argument returns a string representing the current time and date.

(%i1) d : timedate ();
(%o1)                      2010-06-08 04:08:09+01:00
(%i2) print ("timedate reports current time", d) $
timedate reports current time 2010-06-08 04:08:09+01:00

timedate with an argument returns a string representing the argument.

(%i1) timedate (0);
(%o1)                      1900-01-01 01:00:00+01:00
(%i2) timedate (absolute_real_time () - 7*24*3600);
(%o2)                      2010-06-01 04:19:51+01:00

timedate with optional timezone offset.

(%i1) timedate (1000000000, -9.5);
(%o1)               1931-09-09 16:16:40-09:30

Keyboard shortcuts

maxima-core-docs