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
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"
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 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
Additional functions are:
- 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)
- 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);
- 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);
- 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;
}
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