**CIGAL Reference Manual, Chapter 1 (Topics): functions**
===== Functions -- CIGAL Functions =====
In CIGAL, a function is any command that returns
a value. The  value can be a number or any of the other CIGAL data
types: character string, vector, array, matrix, image, or solid (see

[[jvs:cigal:manual:chapter1:variables|VARIABLES(1)]]).  The nature of the returned value depends on the function
and the arguments you give it. Returned values can either be displayed
on the screen, stored in a data variable or used as arguments to other
CIGAL commands (but not to other functions -- see below).

The following is a summary list of CIGAL's intrinsic functions:
|     =           |-assign values to variables|
|     Accept      |-get data from keyboard, cursor, screen, or current input|
|     Accum       |-compute a running sum of elements within a variable|
|     Acos        |-calculate arc-cosine of a variable|
|     Address     |-get the physical memory address of a variable|
|     Alert       |-display message window and wait for response|
|     Alog        |-calculate anti-logarithm of a variable|
|     Analyze     |-calculate frequency distribution of values within a variable|
|     Angle       |-calculate the angle formed by three points|
|     Area        |-calculate the area within a polygon|
|     Array       |-allocate memory for an array variable|
|     Asin        |-calculate arc-sine of a variable|
|     Atan        |-calculate the arc tangent of a variable or a ratio|
|    Column       |-perform arithmetic column by column within a variable|
|     Compress    |-compress a data variable by removing empty values|
|     Comread     |-read from serial communication port|
|     Convolve    |-convolve a variable using a kernel matrix|
|     Cos         |-calculate the cosine of a variable|
|      Dialog     |-get or set menu items in dialog boxes|
|     File        |-assign a data file to a pointer variable|
|     Filter      |-perform a non-convolution neighborhood transform of an image|
|     Findvec     |-find the vector nearest a specified position|
|     Fit         |-fit a straight line to a curve|
|     Flip        |-flip a 2-D variable around the X or Y axis|
|     Format      |-convert data values to character string, specifying format|
|     Getbox      |-get the upper left and lower right coordinates of a box|
|     Getchar     |-read one character from the keyboard|
|     Getfile     |-get a filename from directory lists interactively|
|     Gettxt      |-read text information from the screen display|
|     Getxyz      |-read the cursor position|
|     Getz        |-read the current Z value (from ZDEV or ZVAL)|
|     Index       |-find the position of a value in a variable|
|     Integer     |-convert floating point number to integer value|
|     Interpolate |-calculate Y values from X values, using a standard curve|
|     Lcase       |-convert a character string to lower case text|
|     Length      |-calculate distance between 2 points or along a vector path|
|     Log         |-calculate the logarithm of a variable|
|     Maklut      |-create a ramped lookup table|
|     Map         |-copy a variable to another through a lookup table|
|     Mask        |-use a mask to select part of a variable|
|     Matrix      |-allocate memory for a matrix or image variable|
|     Max         |-find the maximum value in a variable, or between 2 variables|
|     Mean        |-calculate the mean value of a variable|
|     Measure     |-calculate the length and area of a vector list|
|     Menuitem    |-get information about menu commands|
|     Min         |-find the minimum value in a variable, or between 2 variables|
|     Mode        |-get information about a variable's data and storage type|
|     Pdstr       |-expand a repeated character string sequence|
|     Perp        |-calculate the perpendicular intercept from a point to a line|
|     Pointer     |-create a pointer to a variable|
|     Projection  |-get a variable's scale, offset, rotation, and pin parameters|
|     Ramp        |-generate a ramped sequence of numbers|
|     Random      |-generate a random sequence of numbers|
|     Rank        |-determine the sorted order of elements of a variable|
|     Rem         |-calculate the remainder after performing integer division|
|     RGB         |-convert color data formats|
|     Round       |-convert floating point value to the nearest integer|
|     Row         |-perform arithmetic row by row within a variable|
|     Sample      |-sample data values along a vector path|
|     Search      |-find 1st image value within given intensity range|
|     Shift       |-do bitwise shift of integer data values|
|     Sin         |-calculate the sine of a variable|
|     Size        |-return the number of elements in a variable|
|     Smooth      |-remove kinks by averaging values along a path|
|     Solid       |-allocate memory for a solid variable|
|     Sqrt        |-calculate square root of a variable|
|     Stats       |-return 12 statistics describing a variable|
|     Stdev       |-calculate the standard deviation within a variable|
|     Sum         |-calculate the sum of the values within a variable|
|     Sweep       |-record a number variable and display as on an oscilloscope|
|     Time        |-get current date and time, or elapsed time|
|     Trace       |-generate vector list by tracing an image intensity contour|
|     Transform   |-copy a variable with rotation, scaling, and offset|
|     Ucase       |-convert a character string to upper case text|
|     Vector      |-assign values to a vector variable|
|     Vrbxy       |-get XY position within a WATCHed variable|
|     Warp        |-distort an image by interpolating between fixed points|
|     Xor         |-calculate an "exclusive or" operation on 2 variables|
|     Zoom        |-transform a variable by pixel replication or ommision|
|     Zproj       |-Perform arithmetic by z-column within a solid variable|
\\
|     ( )         |-group operations within an arithmetic expression|
|     ==          |-logical "is equal to" operator|
|     ++          |-auto-increment suffix operator|
|     --          |-auto-decrement suffix operator|
|     %%**%%          |-"raise to the power" operator|
|     //          |-join operator|
|     >>          |-append operator|
|     =           |-assign operator|
|     +           |-addition operator|
|     -           |-subtraction operator|
|     %%*%%       |-multiplication operator|
|     /           |-division operator|
|     >=          |-logical "greater than or equal to" operator|
|     >           |-logical "greater than" operator|
|     %%<=%%          |-logical "less than or equal to" operator|
|     <           |-logical "less than" operator|
|     !=          |-logical "not equal to" operator|
|     !           |-bit-wise complement operator, or Factorial operator|
|     &           |-bit-wise AND operator|
|     %%|%%       |-bit-wise OR operator|
|     ?           |-"query" operator -- gets status of operand|

In general, if a function operand has more than one value, the function
will be repeated for every value, and the output will have as many
values as the inputs.  For binary functions, if the two operands have
different numbers of values the extra values in the larger operand are
simply ignored, UNLESS the smaller operand has only a single value, in
which case the single value will be combined with each element in the
larger operand.

Arguments to functions are usually entered in parentheses (immediately
after the function name) and individual arguments separated by commas.
However, if the function is not being assigned to a variable or combined
with some other command the parentheses can be omitted and the arguments
simply separated by spaces.

Examples:
   (Assume A, B, C, ARAY1, ARAY2, and ARAY3 are previously declared variables.)
   sqrt 2000                                         ; print result
   a = sqrt(2000)                                    ; store result in A
   aray1 = sqrt(aray2)                               ; get SQRT of each value
   aray3 = (a+sqrt(aray1/c))*log(b+aray2)            ; combine as you wish
   text accept("Enter text string: ",,string) 100    ; use ACCEPT as an
                                                     ; argument to TEXT cmd
   type stats(aray1) > stats.dat                     ; store STATS in file

**See Also:**\\
[[jvs:cigal|CIGAL Home]], 
[[jvs:cigal:manual|CIGAL Manual]], 
[[jvs:cigal:manual:chapter1|Topics List]], 
[[jvs:cigal:manual:help|Manual Help]]