Table of Contents
vector - Vector data type for
Tcl
vector configure option value ...
vector create vecName ?vecName...?
?switches?
vector destroy vecName ?vecName...?
vector expr expression
vector
names ?pattern...?
vector op operation vecName ?arg?...
The vector
command creates a vector of floating point values. The vector's components
can be manipulated in three ways: through a Tcl array variable, a Tcl command,
or the C API.
A vector is simply an ordered set of numbers.
The components of a vector are real numbers, indexed by counting numbers.
Vectors are common data structures for many applications. For example,
a graph may use two vectors to represent the X-Y coordinates of the data
plotted. The graph will automatically be redrawn when the vectors are updated
or changed. By using vectors, you can separate data analysis from the graph
widget. This makes it easier, for example, to add data transformations,
such as splines. It's possible to plot the same data to in multiple graphs,
where each graph presents a different view or scale of the data.
You could
try to use Tcl's associative arrays as vectors. Tcl arrays are easy to use.
You can access individual elements randomly by specifying the index, or
the set the entire array by providing a list of index and value pairs for
each element. The disadvantages of associative arrays as vectors lie in
the fact they are implemented as hash tables.
- There's no implied ordering
to the associative arrays. If you used vectors for plotting, you would
want to insure the second component comes after the first, an so on. This
isn't possible since arrays are actually hash tables. For example, you can't
get a range of values between two indices. Nor can you sort an array.
- Arrays
consume lots of memory when the number of elements becomes large (tens
of thousands). This is because each element's index and value are stored
as strings in the hash table.
- The C programming interface is unwieldy. Normally
with vectors, you would like to view the Tcl array as you do a C array,
as an array of floats or doubles. But with hash tables, you must convert
both the index and value to and from decimal strings, just to access an
element in the array. This makes it cumbersome to perform operations on
the array as a whole.
The vector command tries to overcome these disadvantages
while still retaining the ease of use of Tcl arrays. The vector command
creates both a new Tcl command and associate array which are linked to
the vector components. You can randomly access vector components though
the elements of array. Not all indices are generated for the array, so
printing the array (using the parray procedure) does not print out all
the component values. You can use the Tcl command to access the array as
a whole. You can copy, append, or sort vector using its command. If you
need greater performance, or customized behavior, you can write your own
C code to manage vectors.
You create vectors using the vector command
and its create operation.
# Create a new vector.
vector create y(50)
This creates a new vector named y. It has fifty components, by default,
initialized to 0.0. In addition, both a Tcl command and array variable,
both named y, are created. You can use either the command or variable
to query or modify components of the vector.
# Set the first value.
set y(0) 9.25
puts "y has [y length] components"
The array y can be used to read or set individual components of the vector.
Vector components are indexed from zero. The array index must be a number
less than the number of components. For example, it's an error if you try
to set the 51st element of y.
# This is an error. The vector only has 50 components.
set y(50) 0.02
You can also specify a range of indices using a colon (:) to separate the
first and last indices of the range.
# Set the first six components of y
set y(0:5) 25.2
If you don't include an index, then it will default to the first and/or
last component of the vector.
# Print out all the components of y
puts "y = $y(:)"
There are special non-numeric indices. The index end, specifies the last
component of the vector. It's an error to use this index if the vector is
empty (length is zero). The index ++end can be used to extend the vector
by one component and initialize it to a specific value. You can't read
from the array using this index, though.
# Extend the vector by one component.
set y(++end) 0.02
The other special indices are min and max. They return the current
smallest and largest components of the vector.
# Print the bounds of the vector
puts "min=$y(min) max=$y(max)"
To delete components from a vector, simply unset the corresponding array
element. In the following example, the first component of y is deleted.
All the remaining components of y will be moved down by one index as
the length of the vector is reduced by one.
# Delete the first component
unset y(0)
puts "new first element is $y(0)"
The vector's Tcl command can also be used to query or set the vector.
# Create and set the components of a new vector
vector create x
x set { 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 }
Here we've created a vector x without a initial length specification. In
this case, the length is zero. The set operation resets the vector, extending
it and setting values for each new component.
There are several operations
for vectors. The range operation lists the components of a vector between
two indices.
# List the components
puts "x = [x range 0 end]"
You can search for a particular value using the search operation. It returns
a list of indices of the components with the same value. If no component
has the same value, it returns "".
# Find the index of the biggest component
set indices [x search $x(max)]
Other operations copy, append, or sort vectors. You can append vectors
or new values onto an existing vector with the append operation.
# Append assorted vectors and values to x
x append x2 x3 { 2.3 4.5 } x4
The sort operation sorts the vector. If any additional vectors are specified,
they are rearranged in the same order as the vector. For example, you could
use it to sort data points represented by x and y vectors.
# Sort the data points
x sort y
The vector x is sorted while the components of y are rearranged so
that the original x,y coordinate pairs are retained.
The expr operation
lets you perform arithmetic on vectors. The result is stored in the vector.
# Add the two vectors and a scalar
x expr { x + y }
x expr { x * 2 }
When a vector is modified, resized, or deleted, it may trigger call-backs
to notify the clients of the vector. For example, when a vector used in
the graph widget is updated, the vector automatically notifies the widget
that it has changed. The graph can then redrawn itself at the next idle
point. By default, the notification occurs when Tk is next idle. This way
you can modify the vector many times without incurring the penalty of the
graph redrawing itself for each change. You can change this behavior using
the notify operation.
# Make vector x notify after every change
x notify always
...
# Never notify
x notify never
...
# Force notification now
x notify now
# Set Tcl callback for update of Tktable widget .t.
x notify callback {.t conf -padx [.t cget -padx]; .t reread}
To delete a vector, use the vector delete command. Both the vector and
its corresponding Tcl command are destroyed.
# Remove vector x
vector destroy x
The psuedo vector last can be used at the end of an expression to implement
running totals. During execution it resolves to the result from the previous
vector element evaluation.
vector create A(10)
vector create B(10)
vector create S(10)
vector create T(10)
S expr A+B
T expr S+last; # Running total
Syntax
Vectors are created using the vector create operation. Th create
operation can be invoked in one of three forms:
- vector create vecName
- This
creates a new vector vecName which initially has no components.
- vector create
vecName(size)
- This second form creates a new vector which will contain
size number of components. The components will be indexed starting from
zero (0). The default value for the components is 0.0.
- vector create vecName(rows,columns)
- This form allows creation of a matrix with the specified columns and rows*columns
elements. See the matrix section for more details.
- vector create vecName(first:last)
- The last form creates a new vector of indexed first through last. First
and last can be any integer value so long as first is less than last.
Vector
names must start with a letter and consist of letters, digits, or underscores.
# Error: must start with letter
vector create 1abc
You can automatically generate vector names using the "#auto" vector
name. The create operation will generate a unique vector name.
set vec [vector create #auto]
puts "$vec has [$vec length] components"
Vector Indices
Vectors are indexed by integers. You can access the individual
vector components via its array variable or Tcl command. The string representing
the index can be an integer, a numeric expression, a range, or a special
keyword.
The index must lie within the current range of the vector, otherwise
an an error message is returned. Normally the indices of a vector are start
from 0. But you can use the offset operation to change a vector's indices
on-the-fly.
puts $vecName(0)
vecName offset -5
puts $vecName(-5)
When matrix numcols is > 1, 2D indexes are supported using ROW,COL form.
vecName matrix numcols 3
puts vecName(0,2)
You can also use numeric expressions as indices. The result of the expression
must be an integer value.
set n 21
set vecName($n+3) 50.2
The following special non-numeric indices are available: min, max, end,
and ++end.
puts "min = $vecName($min)"
set vecName(end) -1.2
The indices min and max will return the minimum and maximum values
of the vector. Also available are: prod, sum, and mean. The index
end returns the value of the last component in the vector. he index end,0
returns the value of the last row in column 0 of the vector. The index
++end is used to append new value onto the vector. It automatically extends
the vector by numcols and sets its value.
# Append an new component to the end
set vecName(++end) 3.2
A range of indices can be indicated by a colon (:).
# Set the first six components to 1.0
set vecName(0:5) 1.0
If no index is supplied the first or last component is assumed.
# Print the values of all the components
puts $vecName(:)
Vector Operations
- vector configure ? -flush bool -watchunset bool -oldcreate
bool -maxsize int -novariable bool -nocommand bool?
- The configure operation
sets the default options used in creating vectors: these options are global
to the interpreter. The -maxsize option, when non-zero, limits creation size.
The -oldcreate enable the creation shortcut: vector vec1 vec2 .... See the create
command for details on the others. By default, these are all disabled or
zero.
- vector create vecName?(size)?... ?switches?
- The create operation creates
a new vector vecName. The size may be an integer, a START:END range or ROW,COL
(see matrix). This creates both a Tcl command and array variable called
vecName. The name vecName must be unique, so another Tcl command or array
variable can not already exist in the current scope. You may access the
components of the vector using the variable. If you change a value in
the array, or unset an array element, the vector is updated to reflect
the changes. When the variable vecName is unset, the vector and its Tcl
command are also destroyed.
The vector has optional switches that affect
how the vector is created. They are as follows:
- -variable varName
- Specifies
the name of a Tcl variable to be mapped to the vector. If the variable already
exists, it is first deleted, then recreated. If varName is the empty string,
then no variable will be mapped. You can always map a variable back to the
vector using the vector's variable operation.
- -command cmdName
- Maps a Tcl
command to the vector. The vector can be accessed using cmdName and one
of the vector instance operations. A Tcl command by that name cannot already
exist. If cmdName is the empty string, no command mapping will be made.
- -watchunset
boolean
- Indicates that the vector should automatically delete itself if
the variable associated with the vector is unset. By default, the vector
will not be deleted. This is different from previous releases. Set boolean
to "true" to get the old behavior.
- -flush boolean
- Indicates that the vector
should automatically flush the cached variable elements which unsets all
the elements of the Tcl array variable associated with the vector, freeing
memory associated with the variable. This includes both the hash table
and the hash keys. The down side is that this effectively flushes the caching
of vector elements in the array. This means that the subsequent reads of
the array will require a decimal to string conversion. By default, flushing
is disabled.
- vector destroy vecName ?vecName...?
- Destroy vectors.
- vector expr
expression
All binary operators take vectors as operands (remember that
numbers are treated as one-component vectors).The exact action of binary
operators depends upon the length of the second operand. If the second
operand has only one component, then each element of the first vector operand
is computed by that value. For example, the expression "x * 2" multiples
all elements of the vector x by 2. If the second operand has more than
one component, both operands must be the same length. Each pair of corresponding
elements are computed. So "x + y" adds the the first components of x and
y together, the second, and so on.
The valid operators are listed below,
grouped in decreasing order of precedence:
- - !
- Unary minus and logical
NOT. The unary minus flips the sign of each component in the vector. The
logical not operator returns a vector of whose values are 0.0 or 1.0. For
each non-zero component 1.0 is returned, 0.0 otherwise.
- ^
- Exponentiation.
- *
/ %
- Multiply, divide, remainder.
- + -
- Add and subtract.
- << >>
- Left and
right shift. Circularly shifts the values of the vector
- < > <= >=
- Boolean
less, greater, less than or equal, and greater than or equal. Each operator
returns a vector of ones and zeros. If the condition is true, 1.0 is the
component value, 0.0 otherwise.
- == !=
- Boolean equal and not equal. Each operator
returns a vector of ones and zeros. If the condition is true, 1.0 is the
component value, 0.0 otherwise.
- &&
- Logical AND. Produces a 1 result if both
operands are non-zero, 0 otherwise.
- ||
- Logical OR. Produces a 0 result if both
operands are zero, 1 otherwise.
- x?y:z
- If-then-else, as in C.
See the C manual
for more details on the results produced by each operator. All of the binary
operators group left-to-right within the same precedence level.
Several
mathematical functions are supported for vectors. Each of the following
functions invokes the math library function of the same name; see the manual
entries for the library functions for details on what they do. The operation
is applied to all elements of the vector returning the results. All functions
take a vector operand. If no vector operand is used in the call, the current
vector is assumed. eg.
vector create aVec
aVec seq 0 100
aVec expr {2*abs(aVec)-1}
aVec length 100
aVec expr {2*row()}
vector expr {2*row()} ; # ERROR!
acos cos hypot sinh
asin cosh log sqrt
atan exp log10 tan
ceil floor sin tanh
- abs
- Returns the absolute value of each component.
- random
- Returns a vector of non-negative values uniformly distributed between
[0.0, 1.0) using drand48. The seed comes from the internal clock of the machine
or may be set manual with the srandom function.
- round
- Rounds each component
of the vector.
- srandom
- Initializes the random number generator using srand48.
The high order 32-bits are set using the integral portion of the first
vector component. All other components are ignored. The low order 16-bits
are set to an arbitrary value.
The following functions return a single
value.
- adev
- Returns the average deviation (defined as the sum of the absolute
values of the differences between component and the mean, divided by the
length of the vector).
- kurtosis
- Returns the degree of peakedness (fourth
moment) of the vector.
- length
- Returns the number of components in the vector.
- max
- Returns the vector's maximum value.
- mean
- Returns the mean value of the
vector.
- median
- Returns the median of the vector.
- min
- Returns the vector's
minimum value.
- q1
- Returns the first quartile of the vector.
- q3
- Returns the
third quartile of the vector.
- prod
- Returns the product of the components.
- sdev
- Returns the standard deviation (defined as the square root of the
variance) of the vector.
- skew
- Returns the skewness (or third moment) of
the vector. This characterizes the degree of asymmetry of the vector about
the mean.
- sum
- Returns the sum of the components.
- var
- Returns the variance
of the vector. The sum of the squared differences between each component
and the mean is computed. The variance is the sum divided by the length
of the vector minus 1.
This last set of functions returns a vector of the
same length as the argument.
- invert
- Returns vector with elements in reversed
order.
- norm
- Scales the values of the vector to lie in the range [0.0..1.0].
- row
- Psuedo function to get the current row.
- sort
- Returns the vector components
sorted in ascending order.
- shift(nVec,N)
- This is the only function taking
a second arg. It provides a version of nvec shifted by N places. When N is
a scalar or vector with only one element, shift fills vacant area with
0. Otherwise the second element of nVec is used for the fill value. One use
for this is providing running totals.
- vector names ?pattern?
- Return names
of all defined vectors.
- vector op operation vecName ?arg?...
- Invoke instance
operation. Supported operations are defined in the next section. Op is the
only way to invoke instance operation sub-commands when -command is defined
as empty in a vector. It also allows writing vector code that is checkable
by a syntax checkers. eg.
vector create v1
v1 op append {1 2 3}
v1 op modify 1 2.1
You can also use the vector's Tcl command to query or
modify it. The general form is
vecName operation ?arg?...
Note this is equivalent to the form:
vector op operation vecName ?arg?...
Both operation and its arguments determine the exact behavior of the command.
The operations available for vectors are listed below.
- vecName + item
- vecName
- item vecName * item vecName / item Perform binary op and return result
as a list.
- vecName append item ?item?...
- Appends the component values from
item to vecName. Item can be either the name of a vector or a list of numeric
values.
- vecName binread channel ?length? ?switches?
- Reads binary values
from a Tcl channel. Values are either appended to the end of the vector
or placed at a given index (using the -at option), overwriting existing
values. Data is read until EOF is found on the channel or a specified number
of values length are read (note that this is not necessarily the same
as the number of bytes). The following switches are supported:
- -swap
- Swap
bytes and words. The default endian is the host machine.
- -at index
- New values
will start at vector index index. This will overwrite any current values.
- -format format
- Specifies the format of the data. Format can be one of the
following: "i1", "i2", "i4", "i8", "u1, "u2", "u4", "u8", "r4", "r8", or
"r16". The number indicates the number of bytes required for each value.
The letter indicates the type: "i" for signed, "u" for unsigned, "r" or
real. The default format is "r16".
- vecName binwrite channel ?length? ?-at
index?
- Like binread, but writes data.
- vecName clear
- Clears the element
indices from the array variable associated with vecName. This doesn't affect
the components of the vector. By default, the number of entries in the
Tcl array doesn't match the number of components in the vector. This is
because its too expensive to maintain decimal strings for both the index
and value for each component. Instead, the index and value are saved only
when you read or write an element with a new index. This command removes
the index and value strings from the array. This is useful when the vector
is large.
- vecName delete index ?index?...
- Deletes the indexth component from
the vector vecName. Index is the index of the element to be deleted. This
is the same as unsetting the array variable element index. The vector is
compacted after all the indices have been deleted.
- vecName dup destName
- Copies vecName to destName. DestName is the name of a destination vector.
If a vector destName already exists, it is overwritten with the components
of vecName. Otherwise a new vector is created.
- vecName expr expression
- Computes the expression and resets the values of the vector accordingly.
Both scalar and vector math operations are allowed. All values in expressions
are either real numbers or names of vectors. All numbers are treated as
one component vectors.
- vecName index index ?value?...
- Get/set individual vector
values. This provides element updating when -variable is set to empty.
- vecName
insert index item ?item?...
- Inserts the component values from item to vecName
at index Item can be either the name of a vector or a list of numeric values.
- vecName length ?newSize?
- Queries or resets the number of components in
vecName. NewSize is a number specifying the new size of the vector. If newSize
is smaller than the current size of vecName, vecName is truncated. If newSize
is greater, the vector is extended and the new components are initialized
to 0.0. If no newSize argument is present, the current length of the vector
is returned.
- vecName matrix ...
- Matrix provides a 2D array view into 1D data.
It provides indexing operations in ROW,COL form making it suitable for
use with TkTable. Data storage remains unchanged: vectors are still just
a single long array. For example, here are two ways to create a 3 column
by 10 row matrix:
vector create aVec(10,3)
vector create bVec(30)
bVec matrix numcols 3
set aVec(0,0) 99
set bVec(29,2) -99
aVec append {5 6 7}; # aVec now has 11 rows.
aVec append 1 2; # Now aVec has 13 rows!
Note that data is appended only in increments of numcols. Elements 0-2 make
up the first row, 3-5 the second, etc. Elements will appear only in increments
of the column size.
- vecName matrix copy dstcolumn srccolumn ?srcVec?
- Copy
a column of element values to column dstcolumn from srccolumn. If vector
srcVec is given, and not the same as vecName, the columns numbers must
be different. If the srcVec column is longer, vecName will be extended. If
shorter, remaining destination values are not overwritten.
- vecName matrix
delete column.
- Delete elements in a column. Note that numcols, which must
be greater than 1, will be decremented.
- vecName matrix get column
- Get the
element in a column: this number must be less than numcols. Note that numcols
must be non-zero.
- vecName matrix insert column ?initvalue? .
- Insert a new
column of elements at column (default 0). The new column is initialized
with initvalue, or 0.0 if not specified. Note that numcols will be incremented.
- vecName matrix multiply srcVec ?dstVec?
- Perform matrix multiplication
using srcVec, placing results either in dstVec, or returned as a list. The
numrows of srcVec must equal numcols in vecName. One application for multiply
is coordinate transformation.
- vecName matrix numcols ?size?
- Get or set the
number of columns for a vectors data. Values >1 enable array variables to
accept 2d matrix indexes. For example with a numcols of 10, $vec1(1,2) refers
to the 13th element in the vector. A vectors size is also constrained to
multiples of numcols, as is it's offset. By default, numcols is 1.
- vecName
matrix numrows ?size?
- Get or set the length of rows in a columns for a
vector. By default, this is just the vector length/numcols. Setting this
value simply provides a convenient way to increase or decrease the vector
size by multiples of numcols.
- vecName matrix set column ?valuelist?
- Set
value elements in a column: this number must be less than numcols. The
valuelist is a list values. If this list is shorter than the column, it's
last value is used for all remaining columns. The column gets set to the
values of item, or 0.0 by default.
- vecName matrix shift column amount ?startoffset?
- Shifts the values of a column by integer inamount. A negative value shifts
upward. The startoffset indicates where to start shifting from.
- vecName matrix
sort column ?-reverse?
- Sort the vector by the given column.
- vecName matrix
transpose
- Transpose all columns with rows in matrix. Note that this is a
no-op if numcols is 1. Otherwise, numcols will change to vectorLength/numcols.
- vecName merge srcName ?srcName?...
- Merges the named vectors into a single
vector. The resulting vector is formed by merging the components of each
source vector one index at a time.
- vecName notify ?keyword? ?script?
- Queries
or controls how vector clients are notified of changes to the vector. Also
allows setting a notifier callback. The exact behavior is determined by
keyword.
- always
- Indicates that clients are to be notified immediately
whenever the vector is updated.
- never
- Indicates that no clients are to
be notified.
- whenidle
- Indicates that clients are to be notified at the
next idle point whenever the vector is updated.
- now
- If any client notifications
is currently pending, they are notified immediately.
- cancel
- Cancels pending
notifications of clients using the vector.
- pending
- Returns 1 if a client
notification is pending, and 0 otherwise.
- callback ?script?
- Query or
set a Tcl callback script that is evaluated when a vector is updated.
- vecName
populate destName ?density?
- Creates a vector destName which is a superset
of vecName. DestName will include all the components of vecName, in addition
the interval between each of the original components will contain a density
number of new components, whose values are evenly distributed between the
original components values. This is useful for generating abscissas to
be interpolated along a spline.
- vecName range firstIndex ?lastIndex?...
- Returns
a list of numeric values representing the vector components between two
indices. Both firstIndex and lastIndex are indices representing the range
of components to be returned. If lastIndex is less than firstIndex, the
components are listed in reverse order.
- vecName search value ?value?
- Searches
for a value or range of values among the components of vecName. If one
value argument is given, a list of indices of the components which equal
value is returned. If a second value is also provided, then the indices
of all components which lie within the range of the two values are returned.
If no components are found, then "" is returned.
- vecName set item
- Resets
the components of the vector to item. Item can be either a list of numeric
expressions or another vector.
- vecName seq start ?finish? ?step?
- Generates
a sequence of values starting with the value start. Finish indicates the
terminating value of the sequence. The vector is automatically resized
to contain just the sequence. If three arguments are present, step designates
the interval.
With only two arguments (no finish argument), the sequence
will continue until the vector is filled. With one argument, the interval
defaults to 1.0.
- vecName sort ?-reverse? ?argName?...
- Sorts the vector vecName
in increasing order. If the -reverse flag is present, the vector is sorted
in decreasing order. If other arguments argName are present, they are the
names of vectors which will be rearranged in the same manner as vecName.
Each vector must be the same length as vecName. You could use this to sort
the x vector of a graph, while still retaining the same x,y coordinate
pairs in a y vector.
- vecName split dstName ?dstName?...
- Split the vector into
a multiple vectors. The resulting N vectors each contain the mod-Nth element
from source.
- vecName variable varName
- Maps a Tcl variable to the vector,
creating another means for accessing the vector. The variable varName
can't already exist. This overrides any current variable mapping the vector
may have.
You can create, modify, and destroy vectors from
C code, using library routines. You need to include the header file blt.h.
It contains the definition of the structure Blt_Vector, which represents
the vector. It appears below.
typedef struct {
double *valueArr;
int numValues;
int arraySize;
double min, max;
} Blt_Vector;
The field valueArr points to memory holding the vector components. The
components are stored in a double precision array, whose size size is represented
by arraySize. NumValues is the length of vector. The size of the array
is always equal to or larger than the length of the vector. Min and max
are minimum and maximum component values.
The following
routines are available from C to manage vectors. Vectors are identified
by the vector name.
Blt_CreateVector
- Synopsis:
int Blt_CreateVector (interp, vecName, length, vecPtrPtr)
Tcl_Interp *interp;
char *vecName;
int length;
Blt_Vector **vecPtrPtr;
- Description:
- Creates a new vector vecName with a length of length. Blt_CreateVector
creates both a new Tcl command and array variable vecName. Neither a command
nor variable named vecName can already exist. A pointer to the vector
is placed into vecPtrPtr.
- Results:
- Returns TCL_OK if the vector is successfully
created. If length is negative, a Tcl variable or command vecName already
exists, or memory cannot be allocated for the vector, then TCL_ERROR
is returned and interp->result will contain an error message.
Blt_DeleteVectorByName
- Synopsis:
int Blt_DeleteVectorByName (interp, vecName)
Tcl_Interp *interp;
char *vecName;
- Description:
- Removes the vector vecName. VecName is the name of a vector
which must already exist. Both the Tcl command and array variable vecName
are destroyed. All clients of the vector will be notified immediately that
the vector has been destroyed.
- Results:
- Returns TCL_OK if the vector is
successfully deleted. If vecName is not the name a vector, then TCL_ERROR
is returned and interp->result will contain an error message.
Blt_DeleteVector
- Synopsis:
int Blt_DeleteVector (vecPtr)
Blt_Vector *vecPtr;
- Description:
- Removes the vector pointed to by vecPtr. VecPtr is a pointer
to a vector, typically set by Blt_GetVector or Blt_CreateVector. Both the
Tcl command and array variable of the vector are destroyed. All clients
of the vector will be notified immediately that the vector has been destroyed.
- Results:
- Returns TCL_OK if the vector is successfully deleted. If vecName
is not the name a vector, then TCL_ERROR is returned and interp->result
will contain an error message.
Blt_GetVector
- Synopsis:
int Blt_GetVector (interp, vecName, vecPtrPtr)
Tcl_Interp *interp;
char *vecName;
Blt_Vector **vecPtrPtr;
- Description:
- Retrieves the vector vecName. VecName is the name of a vector
which must already exist. VecPtrPtr will point be set to the address of
the vector.
- Results:
- Returns TCL_OK if the vector is successfully retrieved.
If vecName is not the name of a vector, then TCL_ERROR is returned and
interp->result will contain an error message.
Blt_ResetVector
- Synopsis:
int Blt_ResetVector (vecPtr, dataArr,
numValues, arraySize, freeProc)
Blt_Vector *vecPtr;
double *dataArr;
int *numValues;
int *arraySize;
Tcl_FreeProc *freeProc;
- Description:
- Resets the components of the vector pointed to by vecPtr.
Calling Blt_ResetVector will trigger the vector to dispatch notifications
to its clients. DataArr is the array of doubles which represents the vector
data. NumValues is the number of elements in the array. ArraySize is the
actual size of the array (the array may be bigger than the number of values
stored in it). FreeProc indicates how the storage for the vector component
array (dataArr) was allocated. It is used to determine how to reallocate
memory when the vector is resized or destroyed. It must be TCL_DYNAMIC,
TCL_STATIC, TCL_VOLATILE, or a pointer to a function to free the memory
allocated for the vector array. If freeProc is TCL_VOLATILE, it indicates
that dataArr must be copied and saved. If freeProc is TCL_DYNAMIC, it
indicates that dataArr was dynamically allocated and that Tcl should free
dataArr if necessary. Static indicates that nothing should be done to
release storage for dataArr.
- Results:
- Returns TCL_OK if the vector is
successfully resized. If newSize is negative, a vector vecName does not
exist, or memory cannot be allocated for the vector, then TCL_ERROR is
returned and interp->result will contain an error message.
Blt_ResizeVector
- Synopsis:
int Blt_ResizeVector (vecPtr, newSize)
Blt_Vector *vecPtr;
int newSize;
- Description:
- Resets the length of the vector pointed to by vecPtr to newSize.
If newSize is smaller than the current size of the vector, it is truncated.
If newSize is greater, the vector is extended and the new components are
initialized to 0.0. Calling Blt_ResetVector will trigger the vector to
dispatch notifications.
- Results:
- Returns TCL_OK if the vector is successfully
resized. If newSize is negative or memory can not be allocated for the
vector, then TCL_ERROR is returned and interp->result will contain an
error message.
Blt_VectorExists
- Synopsis:
int Blt_VectorExists (interp, vecName)
Tcl_Interp *interp;
char *vecName;
- Description:
- Indicates if a vector named vecName exists in interp.
- Results:
- Returns 1 if a vector vecName exists and 0 otherwise.
If your application
needs to be notified when a vector changes, it can allocate a unique client
identifier for itself. Using this identifier, you can then register a call-back
to be made whenever the vector is updated or destroyed. By default, the
call-backs are made at the next idle point. This can be changed to occur
at the time the vector is modified. An application can allocate more than
one identifier for any vector. When the client application is done with
the vector, it should free the identifier.
The call-back routine must of
the following type.
typedef void (Blt_VectorChangedProc) (Tcl_Interp *interp,
ClientData clientData, Blt_VectorNotify notify);
ClientData is passed to this routine whenever it is called. You can use
this to pass information to the call-back. The notify argument indicates
whether the vector has been updated of destroyed. It is an enumerated type.
typedef enum {
BLT_VECTOR_NOTIFY_UPDATE=1,
BLT_VECTOR_NOTIFY_DESTROY=2
} Blt_VectorNotify;
Blt_AllocVectorId
- Synopsis:
Blt_VectorId Blt_AllocVectorId (interp, vecName)
Tcl_Interp *interp;
char *vecName;
- Description:
- Allocates an client identifier for with the vector vecName.
This identifier can be used to specify a call-back which is triggered when
the vector is updated or destroyed.
- Results:
- Returns a client identifier
if successful. If vecName is not the name of a vector, then NULL is returned
and interp->result will contain an error message.
Blt_GetVectorById
- Synopsis:
int Blt_GetVector (interp, clientId, vecPtrPtr)
Tcl_Interp *interp;
Blt_VectorId clientId;
Blt_Vector **vecPtrPtr;
- Description:
- Retrieves the vector used by clientId. ClientId is a valid
vector client identifier allocated by Blt_AllocVectorId. VecPtrPtr will
point be set to the address of the vector.
- Results:
- Returns TCL_OK if
the vector is successfully retrieved.
Blt_SetVectorChangedProc
- Synopsis:
void Blt_SetVectorChangedProc (clientId, proc, clientData);
Blt_VectorId clientId;
Blt_VectorChangedProc *proc;
ClientData *clientData;
- Description:
- Specifies a call-back routine to be called whenever the vector
associated with clientId is updated or deleted. Proc is a pointer to call-back
routine and must be of the type Blt_VectorChangedProc. ClientData is a
one-word value to be passed to the routine when it is invoked. If proc is
NULL, then the client is not notified.
- Results:
- The designated call-back
procedure will be invoked when the vector is updated or destroyed.
Blt_FreeVectorId
- Synopsis:
void Blt_FreeVectorId (clientId);
Blt_VectorId clientId;
- Description:
- Frees the client identifier. Memory allocated for the identifier
is released. The client will no longer be notified when the vector is
modified.
- Results:
- The designated call-back procedure will be no longer be
invoked when the vector is updated or destroyed.
Blt_NameOfVectorId
- Synopsis:
char *Blt_NameOfVectorId (clientId);
Blt_VectorId clientId;
- Description:
- Retrieves the name of the vector associated with the client
identifier clientId.
- Results:
- Returns the name of the vector associated
with clientId. If clientId is not an identifier or the vector has been
destroyed, NULL is returned.
Blt_InstallIndexProc
- Synopsis:
void Blt_InstallIndexProc (indexName, procPtr)
char *indexName;
Blt_VectorIndexProc *procPtr;
- Description:
- Registers a function to be called to retrieved the index
indexName from the vector's array variable.
typedef double Blt_VectorIndexProc(Vector
*vecPtr);
The function will be passed a pointer to the vector. The function
must return a double representing the value at the index.
- Results:
- The new
index is installed into the vector.
The following example opens
a file of binary data and stores it in an array of doubles. The array size
is computed from the size of the file. If the vector "data" exists, calling
Blt_VectorExists, Blt_GetVector is called to get the pointer to the vector.
Otherwise the routine Blt_CreateVector is called to create a new vector
and returns a pointer to it. Just like the Tcl interface, both a new Tcl
command and array variable are created when a new vector is created. It
doesn't make any difference what the initial size of the vector is since
it will be reset shortly. The vector is updated when lt_ResetVector is called.
Blt_ResetVector makes the changes visible to the Tcl interface and other
vector clients (such as a graph widget).
#include <tcl.h>
#include <blt.h>
Blt_Vector *vecPtr;
double *newArr;
FILE *f;
struct stat statBuf;
int numBytes, numValues;
f = fopen("binary.dat", "r");
fstat(fileno(f), &statBuf);
numBytes = (int)statBuf.st_size;
/* Allocate an array big enough to hold all the data */
newArr = (double *)malloc(numBytes)
;
numValues = numBytes / sizeof(double);
fread((void *)newArr, numValues, sizeof(double), f);
fclose(f);
if (Blt_VectorExists(interp, "data")) {
if (Blt_GetVector(interp, "data", &vecPtr) != TCL_OK) {
return TCL_ERROR;
}
} else {
if (Blt_CreateVector(interp, "data", 0, &vecPtr) != TCL_OK) {
return TCL_ERROR;
}
}
/*
* Reset the vector. Clients will be notified when Tk is idle.
* TCL_DYNAMIC tells the vector to free the memory allocated
* if it needs to reallocate or destroy the vector.
*/
if (Blt_ResetVector(vecPtr, newArr, numValues, numValues,
TCL_DYNAMIC) != TCL_OK) {
return TCL_ERROR;
}
Incompatibilities
In previous versions, if the array variable isn't global
(i.e. local to a Tcl procedure), the vector is automatically destroyed
when the procedure returns.
proc doit {} {
# Temporary vector x
vector x(10)
set x(9)
2.0
...
}
This has changed. Variables are not automatically destroyed when their
variable is unset. You can restore the old behavior by setting the "-watchunset"
switch.
vector, graph, widget
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