This is browser.info, produced by makeinfo version 4.13 from
browser.texi.

This file documents the Silo browser.

   Copyright (c) 1994 - 2010, Lawrence Livermore National Security, LLC.
LLNL-CODE-425250.  All rights reserved.


File: browser.info,  Node: Top,  Next: Copying,  Up: (dir)

The Silo Browser User Manual
****************************

This document describes the Silo file browser, an application program
built on the Silo library for interactive viewing of Silo database
files.

* Menu:

* Copying::                     Copyright information.
* Invocation::                  Invoking the browser.
* Syntax::                      Command Syntax.
* Functions::                   Builtin Functions.
* Operators::                   Browser operators.
* Internal Variables::          Controlling the browser personality.
* Startup File::                Browser initialization.
* Editing::                     Changing the values of objects.
* Paging::                      Long output is paginated.
* Redirection::                 Sending output to a file or command.
* Interrupts::                  Interrupting a long-running command.
* Examples::                    Some simple examples.


File: browser.info,  Node: Copying,  Next: Invocation,  Prev: Top,  Up: Top

Copyright
*********

Copyright (C) (c) 1994 - 2010, Lawrence Livermore National Security,
LLC.  LLNL-CODE-425250.  All rights reserved.

   Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

   * Redistributions of source code must retain the above copyright
notice, this list of conditions and the disclaimer below.     *
Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the disclaimer (as noted
below) in the documentation and/or other materials provided with
the distribution.     * Neither the name of the LLNS/LLNL nor the names
of its      contributors may be used to endorse or promote products
derived      from this software without specific prior written
permission.

   THIS SOFTWARE  IS PROVIDED BY  THE COPYRIGHT HOLDERS  AND
CONTRIBUTORS "AS  IS" AND  ANY EXPRESS  OR IMPLIED  WARRANTIES,
INCLUDING,  BUT NOT LIMITED TO, THE IMPLIED  WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A  PARTICULAR  PURPOSE ARE  DISCLAIMED.
IN  NO  EVENT SHALL  LAWRENCE LIVERMORE  NATIONAL SECURITY, LLC,  THE
U.S.  DEPARTMENT OF  ENERGY OR CONTRIBUTORS BE LIABLE FOR  ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR  CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT  LIMITED TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR
SERVICES; LOSS  OF USE,  DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER  IN CONTRACT,
STRICT LIABILITY,  OR TORT (INCLUDING NEGLIGENCE OR  OTHERWISE) ARISING
IN  ANY WAY OUT  OF THE USE  OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

   This work was produced at Lawrence Livermore National Laboratory
under Contract No.  DE-AC52-07NA27344 with the DOE.

   Neither the  United States Government nor  Lawrence Livermore
National Security, LLC nor any of  their employees, makes any warranty,
express or  implied,  or  assumes  any  liability or  responsibility
for  the accuracy, completeness,  or usefulness of  any information,
apparatus, product, or  process disclosed, or  represents that its use
would not infringe privately-owned rights.

   Any reference herein to  any specific commercial products, process,
or services by trade name,  trademark, manufacturer or otherwise does
not necessarily  constitute or imply  its endorsement,  recommendation,
or favoring  by  the  United  States  Government  or  Lawrence
Livermore National Security,  LLC. The views  and opinions of  authors
expressed herein do not necessarily state  or reflect those of the
United States Government or Lawrence Livermore National Security, LLC,
and shall not


File: browser.info,  Node: Invocation,  Next: Syntax,  Prev: Copying,  Up: Top

1 The Browser Command Line
**************************

The schnauzer is a small terrier with a wiry coat; the browser is a
utility built on Silo for reading scientific database files.  The
browser command line is

   `browser' [SWITCHES] [`--'] [FILES]...

   The browser recognizes the following command line switches.  Single
letter switches that don't require an argument can be grouped together
(so `-l -q' is the same as `-lq'). When a single-letter switch takes an
argument the argument can appear either immediately after the letter or
as the next argument such as `-l3' or `-l 3'. Long format switches are
introduced by double hyphens and if they take an argument it must
follow an equal sign such as `--eval=exit'.  Command-line options take
effect before the initialization file is read, but also override any
settings made in that file.

   Invoking the browser with the switch `--help' will show a complete
list of command-line switches and their descriptions.

`-A TOLERANCE'
`--absolute=TOLERANCE'
     All absolute differencing tolerances are set to TOLERANCE, a
     floating point number. All variables of the form `$diff_*_abs' are
     set to the specified tolerance.

`-R TOLERANCE'
`--absolute=TOLERANCE'
     All relative differencing tolerances are set to TOLERANCE, a
     floating point number.  All variables of the form `$diff_*_rel' are
     set to the specified tolerance.

`-V'
`--version'
     Prints the browser version number. If no other switches or files
     are specified then the browser will exit after printing the
     version number.

`-d WORDS'
`--diff=WORDS'
     This switch controls the behavior of the `diff' function of the
     browser. The WORDS should be a comma-separated list of key words
     which will be assigned to the `$diff' browser variable. See its
     documentation for details.

`-e EXPRESSION'
`--eval=EXPRESSION'
     The browser expression is evaluated and the result is printed on
     the standard output stream.  More than one expression can be given
     to the browser by using multiple switches.  The expressions will
     be evaluated in the order given after the initialization file is
     read.  When a `-e' switch is present the browser exits after all
     expressions are processed instead of going into interactive mode.
     If standard output is a terminal then the browser pages the output
     in the normal way (see below).  If the interrupt character is
     pressed when an expression is being evaluated, the browser
     aborts(1).

`-E LIST'
`--exclude=LIST'
     The browser `$exclude' variable is set to the comma-separated list
     of names and/or datatypes supplied as an argument to this switch.
     The switch may appear more than once. The names in the `$exclude'
     list will be excluded from recursive `diff' operations. See
     documentation for `$exclude' for details.

`-f INITFILE'
`--file=INITFILE'
     When the browser begins execution it attempts to read the file
     `.browser_rc' in the user's home directory.  If that file isn't
     readable then it tries to read a system-wide browser initialization
     file.  The `-f' command line switch causes the browser to try to
     read the specified file instead.  To prevent the browser from
     reading any initialization file, say `-f /dev/null' (internal
     browser variables are still initialized to default values).  The
     initialization file is opened after the database(s) and therefore
     can contain commands that reference the database(s).

`-h'
`--help'
     Prints a browser usage message. If this is the only switch and no
     file names are specified then the browser will exit after showing
     the usage message.  The usage message will be paged if printed to
     a terminal.

`-l [VALUE]'
`--lowlevel[=VALUE]'
     This switch assigns an integer value to the `$lowlevel' browser
     variable, which causes the browser to load database objects as type
     `DBobject' even if the object is some other composite Silo datatype
     like `DBquadvar'. If VALUE is specified then it will be assigned
     to the `$lowlevel' variable; otherwise the value `1' is assigned.

`-c [VALUE]'
`--checksums[=VALUE]'
     This switch assigns an integer value to the `$checksums' browser
     variable, which controls browser's use of checksums during read.

`-n LINES'
`--height=LINES'
     The browser pages interactive output to prevent it from scrolling
     off the top of the screen. It normally decides how tall the window
     is by making `ioctl' calls, but this switch can be used to
     override that choice. The setting is valid only until the browser
     receives a `SIGWINCH' signal and queries the terminal size.

`-q'
`--quiet'
     This option causes the browser to be less verbose than normal.
     This sets the `$verbosity' variable to zero.

`-o'
`--obase=FORMAT'
     This switch sets the internal variable `$obase' to FORMAT, which
     should be `16' for hexadecimal, `8' for octal, `2' for binary, or
     anything else for the default decimal format. It controls how
     integer, floating-point, character, and string data are displayed.
     The default is that these types of data are displayed with a
     type-dependent `printf' format string which is user defined (e.g.,
     `$fmt_int').

`-r [BOOLEAN]'
`--rdonly[=BOOLEAN]'
     This option assigns a boolean value to the `$rdonly' browser
     variable, which causes the browser to open all subsequent files in
     read-only mode. Files that only have Unix read permission are
     always opened in read-only mode, but the browser issues a warning
     if the user had asked for read-write permission.  If no argument
     is given for this switch then true is assumed. The default if this
     switch does not appear is false.

`-s [BOOLEAN]'
`--single[=BOOLEAN]'
     This option causes the browser to call `DBForceSingle' with a value
     of one or zero depending on whether the argument is true or false.
     If no argument is given then it is assumed to be true.  Calling
     `DBForceSingle' with a non-zero value causes most drivers to return
     floating point data with the C `float' type rather than the default
     `double' type.

`-v'
`--verbose'
     This option causes the browser to be more verbose than normal.
     This sets the `$verbosity' variable to two.

`-w COLUMNS'
`--width=COLUMNS'
     The browser normally breaks lines to prevent them from wrapping
     around from the right margin to the next line. It decides how many
     columns are appropriate by making `ioctl' calls, but this switch
     overrides that choice.

`--debug[=BOOLEAN]'
     Tells Silo to display the names of the Silo API functions as they
     are called. This switch is probably only useful to those who debug
     the browser.


   If Silo database file names are specified then the files are opened
in the order specified and associated with file symbols `$1', `$2',
etc. These are opened before the initialization file is read, which
happens before any `--eval' statements are executed. However, the
command-line options are reevaluated after the initialization file is
read.

   ---------- Footnotes ----------

   (1) In contrast, pressing the interrupt character during an
interactive browser command aborts the command but not the browser.


File: browser.info,  Node: Syntax,  Next: Functions,  Prev: Invocation,  Up: Top

2 Command Syntax
****************

The browser command syntax is quite simple, consisting of function
calls, operators, atoms, and lists. Comments begin with a hash mark and
continue to the end of the line (except in strings). White space is
generally ignored except as a token separator. Statements can be
continued across multiple lines, but a backslash must escape the
linefeed if the partial statement looks syntactically complete.

   A function call is a parenthetical expression where the first
element is the name of the function and the subsequent elements are the
arguments to that function.  Most functions evaluate all their
arguments but others evaluate only some (or none). For example, the
`Assign' function doesn't evaluate its first argument, but rather
assignes the evaluated second argument to the l-value specified by the
first argument. The parentheses can be omitted from around the top-level
function call. Say `help func' (or `(help func)') for a list of all
functions.

   Most browser operators are infix, binary operators. They take two
operands, one on each side of the operator, and call some function which
is bound to the operator. For example the expression `foo=1' is
equivalent to `(Assign foo 1)'. The `{}' operator takes any number of
arguments which appear between the open and close curly braces. Say
`help operators' for a list of all operators.

   The browser has three types of atoms: strings, numbers, and symbols.
A string is a sequence of characters enclosed in single or double
quotes. The normal C escaping mechanism can be used for special
characters within the string. A single quote has no special significance
in a double-quoted string and vice versa.  Numbers are positive or
negative sequences of decimal digits with an optional embedded decimal
point and trailing exponent. An exponent consists of the letter `e' or
`E' followed by an optional sign and one or more decimal digits.  A
symbol is any sequence of alphanumeric characters and may also include
dollar signs, hyphens, underscores, and various other characters
(although their use is discouraged).

   A list consists of zero or more atoms or lists enclosed in
parentheses. Evaluation of the list results in the browser looking up
the functional value of the first member of the list and calling that
function with the subsequent list members as arguments. Evaluation of
the list can be suppressed by using curly braces instead of parentheses
(e.g., `{1 3 5}' is equivalent to `(Quote 1 3 5)')'.

   The browser reads commands interactively from its standard input. If
available, the GNU readline library is used allowing the user to edit
commands as they are entered using Emacs or vi editing commands. To
quote from the readline library (documentation is available at
`http://www.cs.utah.edu/csinfo/texinfo/texinfo.html'):

     Often during an interactive session you type in a long line of
     text, only to notice that the first word on the line is
     misspelled.  The Readline library gives you a set of commands for
     manipulating the text as you type it in, allowing you to just fix
     your typo, and not forcing you to retype the majority of the line.
     Using these editing commands, you move the cursor to the place
     that needs correction, and delete or insert the text of the
     corrections.  Then, when you are satisfied with the line, you
     simply press <RETURN>.  You do not have to be at the end of the
     line to press <RETURN>; the entire line is accepted regardless of
     the location of the cursor within the line.

   The readline library default mode is Emacs.  If you prefer `vi' key
bindings, then create a file called `.inputrc' in your home directory
with the single line `set editing-mode vi'.


File: browser.info,  Node: Functions,  Next: Operators,  Prev: Syntax,  Up: Top

3 Builtin Functions
*******************

Some of the browser functions have more than one form and are overloaded
to do various things depending on the number of actual arguments
supplied. Arguments shown between `[' and `]' are optional.

`array DIMENSIONS ... BASETYPE'
     Creates a new array datatype. The arguments are the size of the
     array in each dimension and the datatype of the array elements.
     The array size arguments can be either integers or strings that
     look like comma- and/or space-separated integers. Browser arrays
     use C element ordering.

`cd DIRNAME [FILESYM]'
     Each file has a current working directory (CWD) which is initially
     set to the root directory (`/'). This command will set the CWD to
     some other directory. The first argument is the name of the new
     CWD. If the name contains special characters it should be enclosed
     in quotes to protect it from the parser. If the name is relative
     (doesn't start with a `/') then the name is looked up with respect
     to the current CWD. The second optional argument is the file or
     list of files whose CWD is being set (default is the file
     represented by the browser variable `$1').  The DIRNAME is a
     string; it is not interpreted by the browser and thus a command
     like `cd $1.domain_0.angle_walls' will fail while `cd
     domain_0/angle_walls $1' would work.

`close FILESYM ...'
     Closes the database files associated with the specified file
     symbols.  If objects exist in the browser memory which are
     associated with the database then the database will be held open
     until those objects no longer exist, but the file symbol will be
     freed so another file can immediately be associated with that
     symbol. This command is equivalent to `FILESYM=nil' (except with
     extra sanity checks).

`diff OBJECTS...'
     Calculates the differences between its arguments similar to the
     Unix `diff' command. If called with an even number of arguments the
     argument list is split in half and each argument from the first
     half is compared with the corresponding argument of the second
     half. If called with no arguments then the argument list will be
     the SILO files from the command-line (`$1', `$2', etc.).  If
     called with just one argument which is an object from the silo
     file `$1' then that object will be compared to an object with the
     same name from file `$2'.  The behavior is influenced by the
     `$diff' browser variable. In general, if no differences are found
     then no output is produced.

`end'
     See `exit'.

`exit [STATUS]'
     Exits the browser with the specified STATUS, an integer constant.
     If no exit status is supplied then zero (success) is assumed.
     Typing the end of file character (usually control-d) at the
     beginning of a line also invokes this command, causing a zero
     (success) exit.

`file FILENAME'
     The Silo database FILENAME is opened and returned but not
     associated with any symbol.  Therefore, as soon as nothing refers
     to the file, it is closed.  One common use of this function is
     with the `ls' or `diff' commands which can take file objects as
     arguments.  For instance, the command `ls (file curv2d.pdb)' opens
     the `curv2d.pdb' file and lists the root directory and `ls (cd
     dirname (file curv2d.pdb))' lists the contents of the DIRNAME
     directory of `curv2d.pdb'.  The file is open for read-write mode
     unless the `$rdonly' browser variable has a non-nil value or the
     file has only read permission.

`help [TOPIC] [DOCSTRING]'
     Shows documentation for various parts of the browser. When invoked
     without arguments it will display a table of contents of `help'
     subcommands. With one argument it will display documentation for a
     help category (e.g., `help run'), a browser internal variable
     (e.g., `help $diff'), a function (e.g., `help diff'), a
     command-line switch (e.g., `help --diff'), an operator (e.g., `help
     "op="'), or the documentation string associated with the specified
     symbol. When invoked with a string argument it will print all help
     categories which contain the specified string (e.g., `help
     "diff"'). When called with two arguments it assigns the second
     argument as the documentation property of the first argument,
     which must be a symbol or string.

`include FILENAME'
     Causes the specified file to be parsed and evaluated. This is often
     useful in user-private initialization files, `~/.browser_rc', where
     the user wants to augment the actions that would normally happen
     in the system-wide browser initialization file. The user-private
     file should contain the line `include $pubinit'.

`ls [FILESYM] [OBJNAMES...]'
     This command lists the contents of the current working directory.
     If no file is specified then the file associated with `$1' is
     used. If a list of files is specified (e.g., `$*') then a listing
     is produced for each of those files. If object names are supplied,
     then only those objects are listed.  The object names can include
     the normal Unix filename wild cards `*', `?', and `[]' (object
     names with `[]' wild cards require quotes so the `[' and `]' are
     not intrepretted as array selectors). Wild card matching is not
     available if the `fnmatch' function was not available when the
     browser was compiled.  If a single object name is supplied and
     that object is a directory, then the contents of that directory
     appear.  An alternative (and shorter) way to list the contents of
     a subdirectory is to type the name of the subdirectory on a line
     by itself (for instance, `dir1').

`'
     Another way to list a directory is to just type the name of the
     directory at the prompt (you can use `.' as the current working
     directory).  So saying `$2.dir' is the same as saying `ls $2 dir'
     and `$2..' is the same as `ls $2' or `ls $2 .'.

`noprint'
     See `print'.

`open FILENAME [FILESYM]'
     The Silo database FILENAME is opened and associated with the
     specified file symbol.  Any database previously associated with
     FILESYM will be closed as soon as all objects associated with that
     file are freed.  If FILESYM is omitted then `$1' is used.  This
     command is equivalent to `FILESYM = FILENAME'. Files are open in
     read-write mode unless the `$rdonly' browser variable has a
     non-nil value or the file has only read permission.

`[no]print EXPRESSION ...'
     Evaluates the expressions and prints (or suppresses) the result of
     each one.  The `print' command is normally not used because the
     browser prints all non-null expressions by default.  However, a
     `noprint' can be used to prevent the default output.

`pwd [FILESYM]'
     Prints the current working directory for the database associated
     with the specified file symbol, list of files, or `$1'. This
     command also prints the name of the database.  This command is
     usually not used because a file symbol appearing by itself causes
     the database name and current working directory to be displayed.

`quit'
     See `exit'.

`typeof EXPRESSION'
     The type of a Silo expression is printed.  For Silo database
     objects the type which is printed is fully qualified and bound to
     actual values. In contrast, printing the actual named type shows
     the unbound values.  For example, if `d' is a Silo quadvar object,
     then `typeof d.dims' might show `[3] int' while `print
     DBquadvar.dims' displays `[self.ndims] int'.



File: browser.info,  Node: Operators,  Next: Internal Variables,  Prev: Functions,  Up: Top

4 Operators
***********

A browser expression is composed of terms and operators. The following
operators are supported and overloaded depending on the number and type
of arguments.

SYMBOL `=' VALUE
     Assigns a value to a browser internal variable or a database
     object.  If SYMBOL is an internal variable and VALUE is the word
     `nil' then the symbol loses its variable value.

FILESYM `.' VARNAME
     The variable or directory with the name VARNAME is loaded from the
     database associated with the specified file symbol and the Silo
     data object is returned.  The variable name must be enclosed in
     quotes unless it looks like a symbol and does not conflict with a
     browser internal variable. If FILESYM is `$1' and the variable
     name is not enclosed in quotes and is not the name of an internal
     browser variable, then the file symbol and dot can be omitted.
     Thus `$1.quadmesh' can be written as just `quadmesh'.

SDO `.' FIELDNAME
     If SDO is some Silo data object which has a structured type, then
     this expression returns a new Silo data object which is the
     specified field of the SDO structure.  For instance, a quadmesh
     `qm' has a field named `dims' which holds the dimensions of the
     mesh.  The expression `qm.dims' returns just the dimensions.

LIST `.' ANYTHING
     If the first argument is a list then the dot operator is applied
     to each member of the list and the result is a list of the results.

SDO `[' ELMTNUM `]'
     If SDO is some Silo data object which has an array type, then this
     expression returns the single specified element of that array.  The
     first element of an array is number zero.  For instance,
     `qm.dims[0]' returns the size of the first mesh dimension.

SDO `[' MIN `:' MAX `]'
     If SDO is some Silo data object which has an array type, then this
     expression returns a sub-array with elements MIN through MAX,
     inclusive.  Thus, `qm.dims[0:2]' are the first three mesh
     dimensions.

SDO `[' EXPR1`,' EXPR2`,' ... `]'
     If SDO is some Silo data object which has an array type, and EXPR
     are element numbers or ranges, then one EXPR is applied to each
     array dimension in turn, automatically skipping over pointers.
     For instance, if a quadvar `qv' has a `vals' of type `*[2]
     *[36000] float' then the expression `qv.vals[0,100:199]' will be
     an object consisting of the second 100 values of the first
     variable.  (The expression `qv.vals[0][100:199]' would result in an
     error message because `qv.vals[0]' returns an object with the type
     `[1] *[36000] float' to which is then applied the `[100:199]' that
     is invalid because the array only has one element.)

EXPR `|' COMMAND
     The expression EXPR has its output redirected to the shell command
     COMMAND.

EXPR `>' FILE
     The expression EXPR has its output redirected to the file FILE,
     which is created or truncated.

EXPR `>>' FILE
     The expression EXPR has its output appended to the file FILE,
     which is created if it doesn't exist.

`{' EXPRESSIONS `}'
     This operator takes zero or more operands occurring between the
     curly braces (optionally separated by commas) and returns a list
     of those unevaluated operands. If only one operand is given then
     that operand is returned unevluated and not in a list.

MINIMUM `:' MAXIMUM
     The range operator is used to construct a range object which
     represents all integers between MINIMUM and MAXIMUM, inclusive.



File: browser.info,  Node: Internal Variables,  Next: Startup File,  Prev: Operators,  Up: Top

5 Internal Variables
********************

Certain aspects of the browser can be configured by setting browser
variables with the `=' operator described above.  The current value of
an internal variable can be displayed by typing the variable's name.
The variables are initialized with default values when the browser
starts and may then be overridden by command-line options, the
initialization file, or interactively. All predefined browser variables
begin with a dollar sign.

* Menu:

* Differencing Variables::
* Output Variables::
* File Variables::


File: browser.info,  Node: Differencing Variables,  Next: Output Variables,  Prev: Internal Variables,  Up: Internal Variables

5.1 Differencing Variables
==========================

These variables affect the operation of the `diff' function.

`$diff'
     This variable's value is a list of symbols which control the
     details of the `diff' function. The default is `$diff = {detail,
     two_column}'. This variable is set by the `--diff' command-line
     switch.

    `detail'
          This is the default, which causes the `diff' function to
          report all details about detected differences.

    `brief'
          If this word is present then `diff' doesn't actually display
          any data. The output will consist of a single line for each
          file object which differs between file A and file B.  This
          option allows some short circuiting of the work required for
          the `detail' mode.

    `summary'
          This key word causes `diff' to report by a single line of
          output when the two operands of the `diff' function are
          different. No output is produced if they are the same. This
          option allows some short circuiting of the work required for
          the `brief' mode.

    `ignore_additions'
          If this is specified then `diff' will not report differences
          due to data appearing in file B but not in file A.

    `ignore_deletions'
          If this is specified then `diff' will not report differences
          due to data appearing in file A but not in file B.

    `two_column'
          If this is specified then the output will list differences
          side-by-side instead of one after the other (that is, output
          will resemble `pdbdiff' instead of `diff'). This setting is
          only applicable for detailed output.

`$exclude'
     The `diff' function normally recurses into directories and compares
     the contents of those directories. However, the `$exclude' variable
     can be a list of character strings which specify object names
     and/or types which should be excluded from recursive comparison.
     The object names may include shell wildcards such as `*', `?', and
     `[]'. If a name pattern is relative (doesn't start with a slash) it
     will be compared to the base name of the objects about to be
     differenced; but if the name pattern is absolute (begins with a
     slash) it will be compared to the full path names of the objects
     being differenced. If the `$exclude' string begins with the string
     `type:' then the following part should be one of the object types
     printed by the `ls' function.  A difference operation between two
     objects is suppressed if either object matches any of the strings
     stored in the `$exclude' list.

     For example, to prevent `diff' from comparing any objects with the
     base name `cycle', or any objects whose full name is
     `/VM/typelist', or any objects whose name ends with `_list', or
     any object of type `obj' one would issue the following browser
     command:

          > $exclude = {"cycle", "/VM/typelist", "*_list", "type:obj"}

     or invoke the browser with the switch
          --exclude='cycle,/VM/typelist,*_list,type:obj'

`$diff_int8_abs'
`$diff_int8_rel'
`$diff_short_abs'
`$diff_short_rel'
`$diff_int_abs'
`$diff_int_rel'
`$diff_long_abs'
`$diff_long_rel'
`$diff_float_abs'
`$diff_float_rel'
`$diff_double_abs'
`$diff_double_rel'
     These variables control how the `diff' function determines whether
     two numeric values are the same or different. The ones that end
     with `_abs' specify the maximum absolute difference allowed
     between two values A and B.  The `diff' command considers A and B
     to be different if `|A-B|>ABS'.  The variables that end with
     `_rel' specify the maximum absolute difference relative to the
     mean of two values.  The `diff' command considers A and B to be
     different if `|A-B|/|A+B| > REL/2'.

     If both tests are performed then A and B are considered different
     if either test indicates they are different. If an ABS or REL
     parameter is not defined (or has a non-positive value) then the
     corresponding test is not performed. If neither test is performed
     then an exact comparison is used.

     All `diff' variables have a default value of zero and are set by
     the `--absolute' and `--relative' command-line switches.


File: browser.info,  Node: Output Variables,  Next: File Variables,  Prev: Differencing Variables,  Up: Internal Variables

5.2 Output Variables
====================

`$height'
     The height of the output terminal in lines. If set to a positive
     value then the browser will pause after each screenful of
     interactive output (redirected output is unaffected by this
     setting). This variable is set by the `--height' command-line
     switch and is reset whenever the browser receives a window size
     change signal (`SIGWINCH').

`$width'
     The width of the output terminal in characters. The browser will
     try not to print data which would wrap from one line to the next.
     This variable is set by the `--width' command-line switch and is
     reset whenever the browser receives a window size change signal
     (`SIGWINCH').

`$verbosity'
     This variable is set by the `--quiet' and `--verbose' switches.
     The `--quiet' sets it to zero while `--verbose' sets it to two
     (the default is one). Changing its value at runtime changes the
     amount of chatter produced by the browser.

`$truncate'
     If this variable holds a non-negative integer value N, then the
     browser shows only N values of each array; otherwise all values of
     an array are displayed. Values which are omitted are indicated by a
     string such as `...(2000 values omitted)...' appearing at the point
     where the values were omitted. Truncation is disabled (all values
     are printed) by setting this variable to nil (its default).

`$trailing'
     If this variable holds a positive integer value and `$truncate'
     has a non-negative integer value, then up to N of the printed
     array values will come from the end of the array rather than the
     beginning. The default value is 50.

`$fmt_double'
     This variable holds a `printf' format string which is used to
     format C `double' values.  The default value is `%1.10g'.

`$fmt_float'
     This variable holds a `printf' format string which is used to
     format C `float' values.  The default value is `%1.5g'.

`$fmt_int'
     This variable holds a `printf' format string which is used to
     format integer values.  The default value is `%d'.

`$fmt_long'
     This variable holds a `printf' format string which is used to
     format long integer values.  The default value is `(long)%ld'.

`$fmt_null'
     This variable holds a `printf' format string which is printed for
     null character strings.  The default value is `(null)'.

`$fmt_int8'
     This variable holds a `printf' format string which is used to
     format 8-bit integer values.  The default is `(int8)%d' but people
     often like to change it to ``%c'' to see the ASCII equivalent. Be
     warned that output of non-printable ASCII characters in this
     manner may not work if the terminal emulator interprets them as
     commands.

`$fmt_short'
     This vairable holds a `printf' format string which is used to
     format short integer values.  The default value is `(short)%d'.

`$fmt_string'
     This variable holds a `printf' format string which is used to
     format character string values.  The default value is `\"%s\"'.

`$obase Output of primitive data (integer, character, string, and'
     floating-point), by default, uses the `$fmt_' variables described
     above. However, by setting this variable to 16, 8, or 2 it is
     possible to display primitive data in hexadecimal, octal, or
     binary format.



File: browser.info,  Node: File Variables,  Prev: Output Variables,  Up: Internal Variables

5.3 File Variables
==================

`$pubinit'
     This variable holds the name of the public initialization file and
     is intended to be used as the first argument to the `include'
     function in a user-private initialization file.

`$lowlevel'
     If this variable has any true value (nil, zero, and the empty
     string are considered false), then the browser reads objects as
     type `DBobject' even if that object has some other datatype such as
     `DBquadvar'.  This variable is set by the `-l' command-line option
     and is useful for debugging the low layers of Silo. The default
     value is zero.

     If the value is two or higher then the Silo definition of
     `DBobject' is used and the values of the `comp_names' and
     `pdb_names' arrays become part of the object.

     If the value is one or two then the browser translates the Silo
     `DBobject' structure into a structure which is more user friendly
     by adding additional members to the object structure. Each member
     has a name from the `comp_names' array and a value based on the
     corresponding member of the `pdb_names' array(1).

`$checksums'
     If this variable has any true value (nil, zero, and the empty
     string are considered false), and the database being read includes
     checksums, then the browser performs checksum checks during read.
     Note that currently, the only Silo driver that supports checksums
     is the HDF5 driver.

     If checksum checks are disabled, then if browser encounters
     corrupt data, it will not know it. In particular, if checksums are
     disabled, the diff operator can wind up reporting corrupted data
     as diffs. If checksums are enabled, however, and the database
     being read includes checksums, then browser will report errors
     when it encounters corrupt data and fail to read the associated
     Silo object. See the associated Silo call `DBSetEnableChecksums()'
     for more information.

`$rdonly'
     If this variable has any true value (nil, zero, and the empty
     string are considered false), then the browser opens files in
     read-only mode instead of read-write mode.  Editing will not work
     on a file open for reading only.

   ---------- Footnotes ----------

   (1) Changes should not be made to the `comp_names' or `pdb_names'
arrays since the Silo `DBobject' is regenerated from the user-friendly
fields before being saved back to the file.


File: browser.info,  Node: Startup File,  Next: Editing,  Prev: Internal Variables,  Up: Top

6 Initializing the Browser
**************************

When the browser starts, it looks for a file called `.browser_rc' in
the user's home directory or a file called
`/usr/local/include/browser_rc'(1).  However, an alternate startup file
can be specified with the `--file' browser command-line switch.  The
browser reads and executes each command found in the startup file.

   The startup file should contain an assignment to the
`$browser_version' variable which will be used to check that the
version of the startup file is appropriate for the browser being run.
Mismatched version numbers result in a rather verbose warning message
(provided that the browser was even able to process the startup file).

   The `$browser_version' number should be assigned some real constant
like `3.004' where `3' is the browser major version number and `004' is
the browser minor version number.  To determine what version number to
specify, invoke the browser as `browser --version'.

   ---------- Footnotes ----------

   (1) The path name may be different depending on how the browser was
compiled.


File: browser.info,  Node: Editing,  Next: Paging,  Prev: Startup File,  Up: Top

7 Editing Database Objects
**************************

The `=' operator can be used to set the value of an internal browser
variable or to change the value of a database object.  If the left hand
side of the `=' is an internal variable, then the value of the internal
variable is changed. Otherwise if the left hand side is a database
object, its value is changed.  Otherwise, a new internal variable is
created and assigned an initial value.

   The browser can change values for objects of type `DBobject' (most
objects are of this type if the browser is running in low-level mode) or
objects under the `var(s)' category in a directory listing.

   When changing the value of a string database object like
`_fileinfo', the new value will be truncated to the same length as the
old value because of limitations in the underlying Silo database
drivers.  This does not apply to string fields of a `DBobject'.

   Assigning a scalar value to an array or slice of an array results in
all selected elements of the array to be set to the same value.  For
instance, if the type of `u_data' is `[31, 41, 31] float' then the
statement `u_data[5]=0' sets all elements of "row" five to zero.


File: browser.info,  Node: Paging,  Next: Redirection,  Prev: Editing,  Up: Top

8 Paging
********

The browser keeps track of how many lines of output have been displayed
for the currently executing command and temporarily pauses that command
whenever output is about to scroll off the top of the screen.  The
height and width of the screen is determined by the browser making
certain `ioctl' calls at startup and each time it gets a `SIGWINCH'
signal.  The initial values can be set with `--height' and `--width'
command-line switches.  If the appropriate `ioctl' is not available
then the values of environment variables `LINES' and `COLUMNS' will be
used. If all else fails then the browser uses zero for the number of
lines (that is, no paging of output) and 80 for the number of columns.

   When the browser pauses the output, the message `more? ('q' to
quit)' is displayed. The following user responses are recognized:

Quit
     Cancels the command and returns to the browser prompt. This is
     equivalent to the browser receiving a `SIGPIPE' signal.

Continue
     Pressing the EOF key (usually control-`d') causes the command to
     continue without being paged. Output will simply scroll off the
     screen).

Next Diff
     Pressing `n' causes output to be suspended until the next file
     difference report or the next non-diff command.

Interrupt
     Pressing the interrupt key (usually control-`c') causes the command
     to be interrupted as usual.

   Output redirected to a file or command is not paged.  If the user is
not satisfied with the limited paging ability of the browser, the output
from a command can be redirected to the pager of the user's choice using
output redirection.


File: browser.info,  Node: Redirection,  Next: Interrupts,  Prev: Paging,  Up: Top

9 Redirection
*************

Output from any browser command can be redirected to a file or shell
command by appending a redirection character and file name or shell
command to the end of the command.

   To save the output of a command in a file, destroying the previous
contents of the file if any, append a `>' and the name of the file.
Unless the file name looks like a browser symbol it must be enclosed in
quotes.  For instance, `quadvar3d > saved' saves the value of Silo
database variable `quadvar' in a text file named `saved'.

   To append the output of a command to a file, append a `>>' and the
file name to the end of the command.  Unless the file name looks like a
browser symbol it must be enclosed in quotes.  For example, `typeof
quadvar3d >> saved' appends type information to the `saved' file.

   To send the output of a browser command to the standard input of a
shell command, follow the browser command with a `|' followed by the
shell command in quotes.  The quotes are not necessary if the shell
command is a single symbol.  Since paging is disabled when output is to
a shell command, one way to display a result without paging is to pipe
the output through the `cat' command like `d | cat'.


File: browser.info,  Node: Interrupts,  Next: Examples,  Prev: Redirection,  Up: Top

10 Interrupts
*************

Since some commands may require a long time to execute or produce a huge
amount of output, the user may want to abort the command before it
finishes.  If the output is paged interactively to the screen then
pressing `q' at the `more?'  prompt accomplishes this.  Otherwise the
user can press the interrupt character (usually control-c) and the
browser command will be immediately terminated and the browser will
prompt for the next command.  If the interrupt character is typed
during command input the browser itself terminates.

   If output from a browser command is being piped into a shell command
and the shell command exits (or closes its standard input) before the
browser command is finished, the browser command gets the `SIGPIPE'
signal and terminates.


File: browser.info,  Node: Examples,  Prev: Interrupts,  Up: Top

11 Examples
***********

This chapter contains some sample output from the browser.

   Normally, you will specify the name of a database file on the browser
command-line(1) like in the following example, and sometimes it's
convenient to open multiple files at the same time.  Each file name
listed on the command-line is given an identifier like `$1', `$2',
etc., and most of the browser commands operate on file `$1' by default.

     % browser rect3d.pdb
     INFO: opening `rect3d.pdb' as $1

   The `ls' command is similar to the Unix `ls' command in that it
lists the contents of the current working directory.  The heading
fields on the left of the equal signs apply until the next heading.  The
headings are the same as those used by MeshTV.  To list the contents of
some subdirectory, say `ls', `ls dir1', `print dir1', or just `dir1'.

     > ls
     qmesh(s)          = quadmesh3d

     qvar(s)           = d                      p
                       = t                      u
                       = v                      w

     mat(s)            = mat1

     var(s)            = _fileinfo              _meshtv_defvars
                       = _meshtvinfo            cycle
                       = d_data                 d_dims
                       = d_maxindex             dtime
                       = mat1_dims              mat1_matlist
                       = mat1_matnos            mat1_mix_mat
                       = mat1_mix_next          mat1_mix_vf
                       = mat1_mix_zone          p_data
                       = p_dims                 p_maxindex
                       = quadmesh3d_align_nodal quadmesh3d_align_zonal
                       = quadmesh3d_coord0      quadmesh3d_coord1
                       = quadmesh3d_coord2      quadmesh3d_dims
                       = quadmesh3d_max_extents quadmesh3d_max_index_n
                       = quadmesh3d_max_index_z quadmesh3d_min_extents
                       = quadmesh3d_min_index   quadmesh3d_zonedims
                       = t_data                 t_dims
                       = t_maxindex             time
                       = u_data                 u_dims
                       = u_maxindex             v_data
                       = v_dims                 v_maxindex
                       = w_data                 w_dims
                       = w_maxindex

   To keep the size of these examples small, we've specified that at
most 50 values should be printed from each array and that 25 of those
values should be from the end of the array (and the other 25, from the
beginning).  To truncate everything say `$truncate=0' and to turn
truncating off say `$truncate=nil'.

     > $truncate = 50
                       = 50
     > $trailing = 25
                       = 25

   The user can ask for the type of any object, including types built
into the browser.  If the object is a structured type (like in this
example) then the type of each component of that structure is printed.

     > typeof d
                       = struct DBquadvar {
     id                =    +0 int
     name              =    +4 string
     units             =    +8 string
     label             =    +12 string
     cycle             =    +16 int
     time              =    +20 float
     dtime             =    +24 double
     meshid            =    +32 int
     datatype          =    +40 int (DBdatatype)
     nels              =    +44 int
     nvals             =    +48 int
     ndims             =    +52 int
     dims              =    +56 [3] int
     major_order       =    +68 int (array order)
     stride            =    +72 [3] int
     min_index         =    +84 [3] int
     max_index         =    +96 [3] int
     origin            =    +108 int
     align             =    +112 [3] float
     mixlen            =    +128 int
     use_specmf        =    +132 int (on/off)
     mixvals           =    +124 *[1] *[0] float
     vals              =    +36 *[1] *[36000] float
                       = }

   An integer following a plus sign indicates that the type corresponds
to a byte offset from the beginning of the innermost enclosing structure
or array.

   A `*' means the object is a pointer to whatever type follows(2).

   A list of array dimensions between `[' and `]' mean that the object
is an array and each element of the array is the type that follows the
`]'.

   The final name is always one of the browser integral types `string'
(same as the C `char*'), `short', `int', `long', `float', or `double'.
If the integral type name is followed by parentheses then the
parentheses contain the name of an underlying C `enum' type or a set of
related C preprocessor constants.

   Some data objects override one or more standard class methods.  Such
objects will have flags like `__FLAG__' which appear inside the object
type.

   One can also ask for the Silo definition of a named data type like
`DBquadvar'.  This prints the definition of the Silo `DBquadvar'
structure which is the same as printed above for the type of `d' except
that array sizes and some primitive types are not bound to actual
values yet(3).

     > DBquadvar
                       = struct DBquadvar {
     id                =    +0 int
     name              =    +4 string
     units             =    +8 string
     label             =    +12 string
     cycle             =    +16 int
     time              =    +20 float
     dtime             =    +24 double
     meshid            =    +32 int
     datatype          =    +40 int (DBdatatype)
     nels              =    +44 int
     nvals             =    +48 int
     ndims             =    +52 int
     dims              =    +56 [self.ndims] int
     major_order       =    +68 int (array order)
     stride            =    +72 [self.ndims] int
     min_index         =    +84 [self.ndims] int
     max_index         =    +96 [self.ndims] int
     origin            =    +108 int
     align             =    +112 [self.ndims] float
     mixlen            =    +128 int
     use_specmf        =    +132 int (on/off)
     mixvals           =    +124 *[self.nvals] *[self.mixlen]
     mixvals           =    self.datatype
     vals              =    +36 *[self.nvals] *[self.nels] self.datatype
                       = }

   Giving just the name of the Silo object is short for `print $1.d'.
Notice that the `vals' array has been truncated as requested and that
MIXVALS has no value. The subscripts in the labels to the left of the
equal sign correspond to the first value on that line (an entire array
in the case of `vals[0]'.

   One can also ask for tye type of a single structure component by
typing the command `DBquadvar.vals'.

     > d
                       = DBquadvar: struct
     id                =    0
     name              =    "d"
     units             =    (null)
     label             =    (null)
     cycle             =    48
     time              =    4.80000
     dtime             =    4.8000000000
     meshid            =    0
     datatype          =    float
     nels              =    36000
     nvals             =    1
     ndims             =    3
     dims[0]           =    {30, 40, 30}
     major_order       =    row major
     stride[0]         =    {1, 30, 1200}
     min_index[0]      =    {0, 0, 0}
     max_index[0]      =    {29, 39, 29}
     origin            =    0
     align[0]          =    {0.50000, 0.50000, 0.50000}
     mixlen            =    0
     use_specmf        =    off
     mixvals           =    NULL
     vals[0]           =    {{0.83957, 0.82083, 0.80304, 0.78626, 0.77056,
     vals[0, 5]        =    0.75601, 0.74266, 0.73059, 0.71987, 0.71055,
     vals[0, 10]       =    0.70269, 0.69633, 0.69153, 0.68831, 0.68669,
     vals[0, 15]       =    0.68669, 0.68831, 0.69153, 0.69633, 0.70269,
     vals[0, 20]       =    0.71055, 0.71987, 0.73059, 0.74266, 0.75601,
     vals[0, 25]       =    ...(35950 values omitted)..., 0.75601,
     vals[0, 35976]    =    0.74266, 0.73059, 0.71987, 0.71055, 0.70269,
     vals[0, 35981]    =    0.69633, 0.69153, 0.68831, 0.68669, 0.68669,
     vals[0, 35986]    =    0.68831, 0.69153, 0.69633, 0.70269, 0.71055,
     vals[0, 35991]    =    0.71987, 0.73059, 0.74266, 0.75601, 0.77056,
     vals[0, 35996]    =    0.78626, 0.80304, 0.82083, 0.83957}}

   The browser does not attempt to be efficient about loading objects
from the database into memory since the underlying Silo library makes it
difficult to do so.  However, if one says `$lowlevel=1' then the
browser uses lower-level Silo functions to read the file.  As a result,
less data is moved from disk to memory.

     > $lowlevel=1
                       = 1
     > d
                       = struct
     name              =    "d"
     type              =    "quadvar"
     meshid            =    "quadmesh"
     align             =    "/quadmesh_align_zonal"
     dims              =    "/d_dims"
     max_index         =    "/d_maxindex"
     value0            =    "/d_data"
     ndims             =    3
     nvals             =    1
     nels              =    36000
     origin            =    0
     datatype          =    19
     mixlen            =    0
     major_order       =    0
     cycle             =    48
     time              =    "/time"
     dtime             =    "/dtime"
     min_index         =    "/quadmesh_min_index"
     use_specmf        =    -1000

   Now we'll decrease the number of values printed and increase the
precision that's displayed for `float' values.

     > $truncate = 12
                       = 12
     > $trailing = 6
                       = 6
     > $fmt_float = "%1.15f"
                       = "%1.15f"
     > d.vals[0]
     [0]               = {0.839570403099060, 0.820833325386047,
     [2]               = 0.803043246269226, 0.786264479160309,
     [4]               = 0.770563006401062, 0.756006062030792,
     [6]               = ...(35988 values omitted)...,
     [35994]           = 0.756006062030792, 0.770563066005707,
     [35996]           = 0.786264479160309, 0.803043246269226,
     [35998]           = 0.820833325386047, 0.839570462703705}

   The `diff' command compares two objects and reports differences
between them.  The output is in groups of differences where the group is
delimited at the beginning and end by a line of stars.  The first half
of the group displays (part of) the first argument to `diff' while the
part of the group after the line of dashes displays (part of) the
second argument.  Subobjects that differ only partially (`stride' in
this case) appear separately before those which completely differ.  The
array truncating parameters apply to each array segment individually.

     > diff d p
     ***************
     stride[1]         = {30, 1200}
     ---------------
     stride[1]         = {31, 1271}
     ***************
     ***************
     name              = "d"
     nels              = 36000
     dims[0]           = {30, 40, 30}
     max_index[0]      = {29, 39, 29}
     vals[0]           = {{0.839570403099060, 0.820833325386047,
     vals[0, 2]        = 0.803043246269226, 0.786264479160309,
     vals[0, 4]        = 0.770563006401062, 0.756006062030792,
     vals[0, 6]        = ...(35988 values omitted)...,
     vals[0, 35994]    = 0.756006062030792, 0.770563066005707,
     vals[0, 35996]    = 0.786264479160309, 0.803043246269226,
     vals[0, 35998]    = 0.820833325386047, 0.839570462703705}}
     ---------------
     name              = "p"
     nels              = 39401
     dims[0]           = {31, 41, 31}
     max_index[0]      = {30, 40, 30}
     vals[0]           = {{1.190943479537964, 1.218125700950623,
     vals[0, 2]        = 1.245107889175415, 1.271674990653992,
     vals[0, 4]        = 1.297584056854248, 1.322565793991089,
     vals[0, 6]        = ...(39389 values omitted)...,
     vals[0, 39395]    = 0.000000000000000, 0.000000000000000,
     vals[0, 39397]    = 0.000000000000000, 0.000000000000000,
     vals[0, 39399]    = 0.000000000000000, 0.000000000000000}}
     ***************

   A compound array is composed of zero or more subarrays.  A subarray
can be printed by saying something like `carray.b', but a subarray is
also printed by saying just `b' as long as `b' is not some other type
of object and `b' exists in exactly one compound array.

     > carray
                       = struct
     name              =    "carray"
     id                =    0
     nelems            =    3
     nvalues           =    18
     datatype          =    float
     a[0]              =    {0.00000, 0.34185, 0.64252, 0.86576}
     b[0]              =    {0.98468, 0.98496, 0.86656, 0.64374, 0.34335,
     b[5]              =    0.00159}
     c[0]              =    {-0.34036, -0.64130, -0.86496, -0.98441,
     c[4]              =    -0.98523, -0.86735, -0.64495, -0.34485}

     > b
     [0]               = {0.98468, 0.98496, 0.86656, 0.64374, 0.34335,
     [5]               = 0.00159}

     > b[2]
     [2]               = {0.86656}

   If the file is opened for reading and writing (the default) then
variables can be given new values.  The new values are written back to
the file immediately.

     > _fileinfo
                       = "3D rectilinear test file"
     > _fileinfo = "testing"
                       = "testing"
     > _fileinfo
                       = "testing"

   A scalar variable assigned to an array (or slice of an array) sets
all the elements of that array (or slice) to the specified value.  A
list of values enclosed in curly braces can be assigned to an array (or
slice of an array) causing each element of the array (or slice) to be
set to one of the listed values.

     > typeof v_data
                       = [31, 41, 31] float
     > v_data = 0
                       = 0
     > v_data[0, 0, 2:4]
                       = {0, 0, 0}
     > v_data[0, 0, 2:4] = {0.111, 0.222, 0.333}
                       = {0.111, 0.222, 0.333}
     > v_data
     [0, 0, 0]         = {0, 0, 0.111, 0.222, 0.333, 0,
     [0, 0, 6]         = ...(39389 values omitted)..., 0, 0, 0,
     [30, 40, 28]      = 0, 0, 0}

   Pressing control-c during a browser command aborts the command, but
pressing control-c when the browser is asking for input aborts the
browser.  It is more polite to press control-d or type `exit' instead
since this gives the browser a chance to properly close database files.

     > $truncate = nil
     > d >data_file
     control-c

     Command aborted.
     > control-c
     %

   ---------- Footnotes ----------

   (1) Opening a file on the command line is the same as saying `open
"rect3d.pdb" $1' interactively.

   (2)  Whether or not something is a pointer is generally not
important to using the browser: a 1d array of pointers to 1d arrays of
integers can be treated like a ragged-edge 2d array of integers.

   (3) The word `self' refers to the object corresponding to the
innermost structure which incloses the `self'.



Tag Table:
Node: Top229
Node: Copying1203
Node: Invocation3961
Ref: Invocation-Footnote-111228
Node: Syntax11360
Node: Functions15202
Node: Operators22925
Node: Internal Variables26547
Node: Differencing Variables27202
Node: Output Variables31646
Node: File Variables35148
Ref: File Variables-Footnote-137504
Node: Startup File37689
Ref: Startup File-Footnote-138797
Node: Editing38879
Node: Paging40146
Node: Redirection41862
Node: Interrupts43167
Node: Examples44049
Ref: Examples-Footnote-158650
Ref: Examples-Footnote-258753
Ref: Examples-Footnote-358953

End Tag Table
