Knight Contrib Library

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List of Routines

• DDREAD
• LEGEND
• LEGENDTEST
• NBYTES
• NLINES
• PANELPLOT
• PPI
• READB
• REPLICAS
• SQUARE
• THECOLOR
• TYPEOF
• WEIBULL
• WRGB

Routine Descriptions

 Name:
	ddread
 Purpose:
	This routine reads data in formatted (or unformatted) rows and columns.
	The name stands for Data Dump Read.  By default, comments are
	skipped and the number of columns is sensed.  Many options
	exist, e.g., selecting rows and columns, reading binary data,
	and selecting non-default data type and delimiters.

 Examples:
	junk = ddread(/help)			; get information only
	array = ddread(file)			; read ASCII data
	array = ddread(file,/formatted)		; ditto
	array = ddread(file,object=object)	; read binary data
	array = ddread(file,columns=[0,3])	; get only 1st & 4th columns
	array = ddread(file,rows=lindgen(10)+10); get only 2nd 10 rows
	array = ddread(file,offset=10,last=19)	; get rows (10,19)
	array = ddread(file,/countall)		; count comment lines
	array = ddread(file,/verbose)		; echo comment lines
	array = ddread(file,type=1)		; return bytes, not floats or longs
	array = ddread(file,range=['start text','stop text'])	; text delimiters

	; Place the detailed output from a Lowtran run in a 2-D array---wow!
	output = ddread('lowtran.out',range=['(CM-1) (MICRN)','0INTEGRATED ABSORPTION'])
	% DDREAD: Read 69 data lines selecting 14 of 14 columns; skipped 395 comment lines.
 Usage:
	array = ddread([file][,options][,/help])
 Optional Inputs:
	file = file with data; if omitted, then call pickfile.
 Keywords:
	/formatted, /unformatted = flags to tell IDL whether data format is
		binary or ASCII.  ddread tries to determine the type
		of data but it's not foolproof.
	object = a string containing the IDL declaration for one instance
		of the object in an unformatted file, e.g.,
			'fltarr(4)'
		or
			'{struct,dwell:0.,pitch:0.,yaw:0.,roll:0.}'
	rows = an array to select a subset of the rows in a formatted file
		Does not count comment lines, unless /countallrows is set!
	columns = likewise for columns
	type = data type of the output D=float (if '.' appears) or long
	delimiter = column separater, D=whitespace
	/help = flag to print header
	range = start and stop row or strings,
		e.g. range = ['substring in 1st line','substring in last line']
	offset = start row (read to end of file, unless last set)
	last = stop row (read from start of file, unless offset set)
	/countallrows = flag to count comment rows as well as data rows (D=0)
	/verbose = flag to echo comments to screen
 Outputs:
	array = array of data from the lines (ASCII) or objects (binary)
 Common blocks:
	none
 Procedure:
	After deciding on ASCII or binary, read file and return array.

 Restrictions:
	- Comments can be either an entire line or else an end of a line, e.g.,
		/* C comment. */
		; IDL comment
		Arbitrary text as a comment
		Comment in Fortran
		The next line establishes # of columns (4) & data type (float):
		6. 7 8 9
		This line and the next are both considered comments.
		6 comment because only one of 4 columns appears
		1 2 3 4 but this line has valid data and will be read as data

	- Even if a range of lines is selected with offset, range or last, all
	  lines are read.  This could be avoided.

	- Other routines needed:
	  pickfile.pro	- to choose file if none is given
	  nlines.pro	- to count lines in a file
	  nbytes.pro	- to count bytes in a variable
	  replicas.pro	- to replicate arrays (not scalars as in replicate.pro)
	  typeof.pro	- to obtain the type of a variable

 Modification history:
	write, 22-26 Feb 92, F.K.Knight (knight@ll.mit.edu)
	allow reading with arbitrary delimiter using reads, 23 Mar 92, FKK
	add countallrows keyword and modify loop to read as little
	  data as possible, 20 May 92, FKK
	correct bug if /formatted set, 6 Jul 92, FKK
	add verbose keyword to print comments, 6 July 92, FKK
	correct bug if /rows=...,/countall set, 6 July 92, FKK & EJA
	add a guard against a blank line being converted to a 
	  number, 21 Aug 92, FKK
	allow parital line just before the EOF.  Possibly this isn't the
	  right thing to do, but I decided to allow it.  If the final line
	  is incomplete, the values are still read and the remainder of
	  the line is filled with zeroes. 26 Oct 92, FKK
	allow range keyword to be a string array, 2 Dec 92, FKK
	make default for countallrows be true if range is present, 2 Dec 92, FKK
	add new function (typeof); called in a few places, 2 Dec 92, FKK

(See /host/bluemoon/usr2/idllib/user_contrib/knight/ddread.pro)

 Name:
	legend
 Purpose:
	This procedure makes a legend for a plot.  The legend can contain
	a mixture of symbols, linestyles, Hershey characters (vectorfont),
	and filled polygons (usersym).
 Examples:
	The call:
		legend,['Plus sign','Asterisk','Period'],psym=[1,2,3]
	produces:
		-----------------
		|		|
		|  + Plus sign	|
		|  * Asterisk	|
		|  . Period	|
		|		|
		-----------------
	Each symbol is drawn with a plots command, so they look OK.
	Other examples are given in usage and in optional output keywords.
 Usage:
	legend,items,linestyle=linestyle	; vertical legend at upper left
	legend,items,psym=psym			; ditto except using symbols
	legend,items,psym=psym,/horizontal	; horizontal format
	legend,items,psym=psym,box=0		; sans border
	legend,items,psym=psym,delimiter='='	; embed an '=' betw psym & text
	legend,items,psym=psym,margin=2		; 2-character margin
	legend,items,psym=psym,position=pos	; position of legend
	legend,items,psym=psym,number=2		; plot two symbols, not one
	legend,items,/fill,psym=[8,8,8],colors=[10,20,30]; 3 filled squares
 Inputs:
	items = text for the items in the legend, a string array.
		You can omit items if you don't want any text labels.
		For example, items = ['diamond','asterisk','square'].
 Optional Inputs:
	linestyle = array of linestyle numbers  If linestyle(i) < 0, then omit 
		ith symbol or line to allow a multi-line entry.
	psym = array of plot symbol numbers.  If psym(i) is negative, then a
		line connects pts for ith item.  If psym(i) = 8, then the
		procedure usersym is called with vertices define in the 
		keyword usersym.
	N. B.: Choose either linestyle, psym, neither, or both.  If neither is
		present, only the text is output.  If both linestyle and
		psym parameters are present, they both have to have the
		same number of elements, and normal plot behaviour occurs.
		By default, if psym is positive, you get one point so there is
		no connecting line.
	vectorfont = vector-drawn characters for the sym/line column, e.g.,
		['!9B!3','!9C!3','!9D!3'] produces an open square, a checkmark,
		and a partial derivative, which might have accompanying items
		['BOX','CHECK','PARTIAL DERIVATIVE'].  If vectorfont(i) = '',
		then plots is called to make a symbol or a line, but if
		vectorfont(i) is a non-null string, then xyouts is called.
		There is no check that !p.font is set properly, e.g., -1 for
		X and 0 for PostScript.  This can produce an error, e.g., use
		!20 with PostScript and !p.font=0, but allows use of Hershey
		*AND* PostScript fonts together.
 Optional Keywords:
	/help = flag to print header
	/horizontal = flag to make the legend horizontal
	/vertical = flag to make the legend vertical (D=vertical)
	box = flag to include/omit box around the legend (D=include)
	delimiter = embedded character(s) between symbol and text (D=none)
	colors = array of colors for plot symbols/lines (D=!color)
	textcolors = array of colors for text (D=!color)
	margin = margin around text measured in characters and lines
	spacing = line spacing (D=bit more than character height)
	pspacing = psym spacing (D=3 characters)
	charsize = just like !p.charsize for plot labels
	position = normalized coordinates of the upper left of the legend
	number = number of plot symbols to plot or length of line (D=1)
	usersym = 2-D array of vertices, cf. usersym in IDL manual. (D=square)
	/fill = flag to fill the usersym
 Outputs:
	legend to current plot device
 Optional Output Keywords:
	corners = 4-element array, like !p.position, of the normalized
	  coords for the box (even if box=0): [llx,lly,urx,ury].
	  Useful for multi-column or multi-line legends, for example,
	  to make a 2-column legend, you might do the following:
	    c1_items = ['diamond','asterisk','square']
	    c1_psym = [4,2,6]
	    c2_items = ['solid','dashed','dotted']
	    c2_line = [0,2,1]
	    legend,c1_items,psym=c1_psym,corners=c1,box=0
	    legend,c2_items,line=c2_line,corners=c2,box=0,pos=[c1(2),c1(3)]
	    c = [c1(0)c2(2),c1(3)>c2(3)]
	    plots,[c(0),c(0),c(2),c(2),c(0)],[c(1),c(3),c(3),c(1),c(1)],/norm
	  Useful also to place the legend.  Here's an automatic way to place
	  the legend in the lower right corner.  The difficulty is that the
	  legend's width is unknown until it is plotted.  In this example,
	  the legend is plotted twice: the first time in the upper left, the
	  second time in the lower right.
	    legend,['1','22','333','4444'],linestyle=indgen(4),corners=corners
			; BOGUS LEGEND---FIRST TIME TO REPORT CORNERS
	    xydims = [corners(2)-corners(0),corners(3)-corners(1)]
			; SAVE WIDTH AND HEIGHT
	    chdim=[!d.x_ch_size/float(!d.x_size),!d.y_ch_size/float(!d.y_size)]
			; DIMENSIONS OF ONE CHARACTER IN NORMALIZED COORDS
	    pos = [!x.window(1)-chdim(0)-xydims(0) $
			,!y.window(0)+chdim(1)+xydims(1)]
			; CALCULATE POSITION FOR LOWER RIGHT
	    plot,findgen(10)	; SIMPLE PLOT; YOU DO WHATEVER YOU WANT HERE.
	    legend,['1','22','333','4444'],linestyle=indgen(4),pos=pos
			; REDO THE LEGEND IN LOWER RIGHT CORNER
	  You can modify the pos calculation to place the legend where you
	  want.  For example to place it in the upper right:
	    pos = [!x.window(1)-chdim(0)-xydims(0),!y.window(1)-xydims(1)]
 Common blocks:
	none
 Procedure:
	If keyword help is set, call doc_library to print header.
	See notes in the code.
 Restrictions:
	Here are some things that aren't implemented.
	- It would be nice to allow data and device coords as well.
	- An orientation keyword would allow lines at angles in the legend.
	- An array of usersyms would be nice---simple change.
	- An order option to interchange symbols and text might be nice.
	- Somebody might like double boxes, e.g., with box = 2.
	- Another feature might be a continuous bar with ticks and text.
	- There are no guards to avoid writing outside the plot area.
	- There is no provision for multi-line text, e.g., '1st line!c2nd line'
	  Sensing !c would be easy, but !c isn't implemented for PostScript.
	  A better way might be to simply output the 2nd line as another item
	  but without any accompanying symbol or linestyle.  A flag to omit
	  the symbol and linestyle is linestyle(i) = -1.
	- There is no ability to make a title line containing any of titles
	  for the legend, for the symbols, or for the text.
	- It might be nice to force the legend to be placed at hardwired
	  locations in the plot, e.g., with keywords like /left/bottom for
	  lower left.  Allowing this requires knowing the width of the text
	  before it is printed, which is difficult.
 Side Effects:
 Modification history:
	write, 24-25 Aug 92, F K Knight (knight@ll.mit.edu)
	allow omission of items or omission of both psym and linestyle, add 
	  corners keyword to facilitate multi-column legends, improve place-
	  ment of symbols and text, add guards for unequal size, 26 Aug 92, FKK
	add linestyle(i)=-1 to suppress a single symbol/line, 27 Aug 92, FKK
	add keyword vectorfont to allow characters in the sym/line column,
	  28 Aug 92, FKK

(See /host/bluemoon/usr2/idllib/user_contrib/knight/legend.pro)

 Name:
	legendtest
 Purpose:
	Test the legend procedure.
 Usage:
	.run legendtest
 Inputs:
	none
 Optional Inputs:
	none
 Keywords:
	none
 Outputs:
	legends of note
 Common blocks:
	none
 Procedure:
 Side Effects:
	Sets !20 font to symbol if PostScript and !p.font=0.
 Restrictions:
	With the vectorfont test, you'll get different results for PostScript
	depending on the value of !p.font.
 Modification history:
	write, 27 Aug 92, F.K.Knight (knight@ll.mit.edu)

(See /host/bluemoon/usr2/idllib/user_contrib/knight/legendtest.pro)

 Name:
	nbytes
 Purpose:
	Return the number of bytes in the variable
 Usage:
	nb = nbytes(variable)
 Inputs:
	variable = any IDL variable
 Optional Inputs or Keywords:
	help = flag to print header
 Outputs:
	nb = number of bytes in variable
 Common blocks:
	none
 Procedure:
	Idea from David Stern.
 Modification history:
	write, 22 Feb 92, F.K.Knight
	increase speed by writing to disk only for structures, 10 Sep 92, FKK
	eliminate Unix-specific file (from ali@rsinc.com), 11 Sep 92, FKK

(See /host/bluemoon/usr2/idllib/user_contrib/knight/nbytes.pro)

 Name:
	nlines
 Purpose:
	Return the number of lines in a file
 Usage:
	nl = nlines(file)
 Inputs:
	file = file to scan
 Optional Inputs or Keywords:
	help = flag to print header
 Outputs:
	nl = number of lines in the file.
 Common blocks:
	none
 Procedure:
	Assume ASCII data and read through file.
 Modification history:
	write, 24 Feb 92, F.K.Knight

(See /host/bluemoon/usr2/idllib/user_contrib/knight/nlines.pro)

 Name:
	PANELPLOT
 Purpose:
	Plot many sets of variables on one common set of axes
 Usage:
	panelplot,xdata,ydata,/init,nplots=n,...	; make 1st plot       
	panelplot,xdata,ydata,...			; make 2nd plot
	...
	panelplot,xdata,ydata,...			; make nth plot
 Inputs:
	(the following inputs apply during initialization)
	init	 = flag to initialize for plots
	nplots	 = number of plots on the page

	(the following inputs apply to each individual plot)
	xdata = abscissa values
	ydata = ordinate values
 Optional Inputs:
	(the following inputs apply during initialization)
	charsize = value to override the default value: !p.charsize
	minx  	 = minimum x value to plot
	maxx     = maximum x value to plot
	xtitle	 = title of the x axis
	title	 = main plot title

	(the following inputs apply to each individual plot)
	ytitle	 = the y axis title
	rtitle	 = the plot title on right side of plot
	ltitle	 = the plot title on left side of plot
	yrange	 = array of y ranges for data
 Outputs:
	plot to current device of data
 Restrictions:
	To suppress tick labels, labels are set to blanks.  However, there may
	be more ticks than blanks, producing unwanted labels.  The plot area
	hardwired and will be incorrect for large charsizes.
 Modification history:
	modify multiplot, 12 Nov 91, FKK
	eliminate legend, fills with polyh, etc. 5 Jun 92, FKK
	change keyword mtitle to title, 25 Aug 92, FKK
	add ystyle and xstyle keywords, 2 Oct 92, FKK

(See /host/bluemoon/usr2/idllib/user_contrib/knight/panelplot.pro)

 Name:
	ppi
 Purpose:
	Make a ppi (plan position indicator) plot, named for the early CRT
	displays that presented radar data in polar coordinates. 
	Plot is intensity versus range and azimuth.
	THere are two input forms: for regularly and irregularly gridded data.
 Examples:
	rcs = intarr(360,10)		; DUMMY DATA---SPIRAL RAMP
	for i=0,9 do $
	  rcs(*,i) = (indgen(360)+i*10) mod 360
	azi = indgen(360)		; AZIMUTH BINS
	range = indgen(10)+1		; RANGE BINS
	ppi,rcs,azi,range		; PPI PLOT:
					; 1-deg BINS x 1-UNIT RANGE BINS
	ppi,rcs,azi,range,color=32	; USE 32 COLORS, NOT 8
	ppi,rcs,azi,range,grid=[12,5]	; ADD GRID AT 12 AZIMUTHS & 5 RANGES

	tc = bytarr(6)			; ARRAY FOR COLORS
	col = ['black','cyan','green','yellow','red','white']
	for i = 0,5 do tc(i) = thecolor(col(i))
	ppi,rcs,azi,range,color=tc	; USE AN ARRAY OF COLOR INDICES
 Usage:
	ppi,rcs,azimuth,range[,rangebin=rangebin,azimuthbin=azimuthbin][,option=opt]
  OR
	ppi,data[,rangebin=rangebin,azimuthbin=azimuthbin][,option=opt]
 Inputs:
	rcs = 2-D array of rcs data with dimensions nazim x nrange
	azimuth = 1-D vector of azimuth bins, length nazimuth,
		 ,in degrees CW from North (up)
	range = 1-D vector of range bins, length nrange
  OR
	data = 2-D array of intensities at (r,theta) with dimensions 3 x npts
	where 
		1st dim		contents
		------- 	-----------------------------
		0		range to data point
		1		azimuth of data point in degrees
		2		intensity of data point
	and npts = number of points or sectors to plot
 Optional Keywords:
	rangebin = size of range bin in same units as range (D=range spacing)
	azimuthbin = size of azimuth bin in degrees (D=azimuth spacing)
	help = flag to print header
	rcsrange = data range spanned by colors (D=[min(data),max(data)])
	colors = # of colors in plot (D=8) or array of color indices
	step = step in color table between colors.  The default steps
		through the entire color table. (D=!d.n_colors/colors)
	title,xtitle,ytitle = titles like plot
	position = 4-element array for plot position in window---!d.position
		(D=largest square with margins)
	rangerange = plot limits (D=auto)
	grid = 1 or 2-element array to specify the number of azimuth and range
		grids, (D=none) Example: grid=[12,5] for azimuth every
		30 degrees and range every 25% of range extent
 Outputs:
	polar plot to current device
 Common blocks:
	none
 Procedure:
	If keyword help is set, call doc_library to print header.
	Only points are plotted if bin parameters are omitted; otherwise,
	trapezoids are used to approximate sectors.  For PostScript, the
	actual PostScript commands are written to the file; for other devices,
	polyfill is used.  The reason is that polyfill doesn't use the
	PostScript fill operator.  Instead polyfill uses vectors, which makes
	a gigantic file.  I tried a few sets of PostScript commands, but I
	found that a single arcn did the trick.  Previously, I tried the set 
	<...setrgbcolor newpath...arcn...lineto...arc closepath fill> where
	the ellipsis means the parameters are omitted.  Using only arcn with a
	linewidth equal to the rangebin yields a file about half the length.
	PostScript code is optimized to produce small PS file.
	A halftone screen could be used for color device and few colors.
 Restrictions:
	Only tested for Openwindows and PostScript, but should work for any
	device that allows polyfill.  
 Modification history:
	write, 11-19 Jun 92, F.K.Knight (knight@ll.mit.edu)
	add optional azimuthal and range grids, 23 Jun 92, FKK
	add optional array of color indices, 15 Oct 92, FKK
	TBD, add an optional color bar

(See /host/bluemoon/usr2/idllib/user_contrib/knight/ppi.pro)

 Name:
	readb
 Purpose:
	Procedure to copy the bits of an array to another IDL variable.
	Good for internal conversion, but limited in scope.
	A more general approach would allow other than array input.
 Examples:
    #1
	a = replicate(byte('ff'x),4)	; MAKE A SOURCE ARRAY
	t = intarr(2)			; MAKE A DESTINATION ARRAY
	readb,a,t			; NEW ROUTINE
	print,t				; EQUIVALENT TO: t = fix(a,0,2)
	     -1      -1
    #2
	print, 'test of nested structures'
	print, '========================='
	st1 = {st1, aa:0L, bb:55.}
	a=bindgen(216)			; JUST ENOUGH BYTES!
	b={t1:0L, t2:0.0, t3:lonarr(5,5), t4:fltarr(5,5), t5:st1}
	readb, a, b	
 Usage:
	readb,source,destination[,offset][,/help]
 Inputs:
	source = IDL source array, not a structure
 Optional Inputs:
	offset = offset of starting point measured in elements of source
	  Offset is set if this is a recursive call.  It might also be 
	  set if you want to start reading from the middle of the source array.
	  Note that offset is just like offset in a = fix(source,offset).
 Keywords:
	help = flag to print header
 Outputs:
	destination = IDL destination variable, any type
 Common blocks:
	none
 Procedure:
	If keyword help is set, call doc_library to print header.
	The recursive portion is from Alan Youngblood (support@rsinc.com).
	For a structure, there is a loop through the tags and readb calls
	itself.  For each tag, you reach a conversion line using one of
	byte(), fix(), long(), etc., after which offset is incremented by
	the length of the tag.
 Modification history:
	start with Alan's ideas, 8-10 Sep 92, FKKnight (knight@ll.mit.edu)

(See /host/bluemoon/usr2/idllib/user_contrib/knight/readb.pro)

 Name:
	replicas
 Purpose:
	Replicate an array, as replicate.pro does for scalars or structures.
	Replicas calls replicate if input is a scalar or structure. 
 Usage:
	array = replicas(/help)
	copies = replicas(array,ncopies)
 Inputs:
	array = array to replicate
	ncopies = number of replicas
 Optional Inputs or Keywords:
	help = flag to print header
 Outputs:
	copies = an array of one dimension more than array and filled
		with copies of array
 Common blocks:
	none
 Procedure:
	If keyword help is set, call doc_library to print header.
	This routine could be incorporated into a more general replicate.
	However, the use of the parameter ncopies is not as general as
	in replicate.
 Modification history:
	write, 22 Feb 92, F.K.Knight
	guard against calling replicate with an array of structures, 18 Nov 92, FKK

(See /host/bluemoon/usr2/idllib/user_contrib/knight/replicas.pro)

 Name:
	square
 Purpose:
	Make a square region for plotting with the current device.
 Usage:
	!p.position = square()		; PERMANENTLY SQUARE
	data = [0,1]
	plot,data,position=square()	; SQUARE ONLY FOR THIS PLOT
	plot,data,pos=square(/center)	; DITTO & CENTERED IN WINDOW
	!p.position = square(/top)	; AT TOP MARGIN OF WINDOW
	!p.position = square(/bottom)	; AT BOTTOM MARGIN OF WINDOW
	!p.position = square(/left)	; AT LEFT MARGIN OF WINDOW
	!p.position = square(/right)	; AT RIGHT MARGIN OF WINDOW
	!p.position = square(size=.5)	; HALF THE LARGEST SIZE POSSIBLE
 Optional Inputs:
	position = 4-element array specifying [xll,yll,xur,yur] device coords
 Optional Keywords:
	/help = flag to print header
	/left = flag to place square at left margin
	/center = flag to center the square in the plot window
	/right = flag to place square at right margin
	/top = like right only for vertical direction
	/bottom = like left only for vertical direction
	size = fraction of largest square possible
 Outputs:
	position = 4-element array giving [xll,yll,xur,yur] device coords
 Common blocks:
	none
 Procedure:
	If keyword help is set, call doc_library to print header.
 Restrictions:
 Side Effects:
	If position is omitted, then a plot is necessary and some plotting
	keywords will be altered, e.g., !x.range and !y.range.  This is only
	a momentary change---until the next plot is done.
 Modification history:
	write, 7 Jul 92, F K Knight (knight@ll.mit.edu)
	add /top, /bottom, /left (D), /right, & /center keywords, 10 Jul 92, FKK

(See /host/bluemoon/usr2/idllib/user_contrib/knight/square.pro)

 Name:
	thecolor
 Purpose:
	Function to rob a color index from the current color table and set
	it to the specified color.  Then return the index.
	Options exist for where in the color table the index is chosen.
	Color names come from the Openwindows colors file, q.v. wrgb.pro.
 Usage:
	plot,x,color=thecolor('red')			; plot is red.
	plot,x,color=thecolor('LightGoldenrod3')	; case insensitive
	plot,x,color=thecolor('red',index=!d.n_color-1)
		; the last index set to red
	plot,x,color=thecolor('red',/first)
		; 1st available at the start of the color table (Default)
	plot,x,color=thecolor('red',/last)
		; ditto except at the end of the color table
	tmp = thecolor(/reset)		; forget all previous thecolor calls
 Inputs:
	name = name of color, a string
 Optional Inputs:
	none
 Keywords:
	/help = flag to print header
	index = force the color index to be this value
	/last = choose index from first available at end of color table
	/first = choose the first available at the bottom. (D)
	rgb = output RGB values for the color
	/noindex = flag to simply return the rgb values, leaving the color
		table unchanged
	/reset = flag to kill all current reserved colors but doesn't restore
		the previous color table. Use loadct,n, tvlct,r,g,b or xloadct.
	/list = list the current colors and their indices
	/show = list all available colors
	/view = show swatches of all available colors; call wrgb widget
 Outputs:
	index = function return
 Optional outputs:
	none (cf. keyword rgb)
 Common blocks:
	thecolor, used to remember available names and info from
	previous calls, containing:
	  thecolors = names of colors stored in previous calls to thecolor
	  thecolorindices = corresponding color table indices (those replaced)
	  thecolornames = list of available color names, read from file
	  thecolorrgb = corresponding rgb triples
	  previousfirstindex = previous index stored at start of color table
	  previouslastindex = previous index stored at end of color table
 Procedure:
	If keyword help is set, call doc_library to print header.
 Restrictions:
	Needs a file where color names and RGB values are found.
	Two files are hardwired; at least one needs to be present.
	The widget xdisplayfile is called if /show is set.
	The widget wrgb is called if /view is set.
 Modification history:
	write, 29 Nov 91, F.K.Knight (knight@ll.mit.edu)
	add keyword noindex to simply return the rgb values and not alter the
	  color table, 27 Apr 92, FKK
	add keyword reset, 30 Jun 92, FKK
	fix bug when /last occurs after /first, 30 Jun 92, FKK
	make a generic file the default, 6 Oct 92, FKK

(See /host/bluemoon/usr2/idllib/user_contrib/knight/thecolor.pro)

 Name:
	typeof
 Purpose:
	Function to return the type of the variable---a shorthand
	for extracting the type from the array returned by size.
 Usage:
	if typeof(variable) eq 7 then message,'Variable is a string.'
 Inputs:
	variable = any IDL variable
 Optional Inputs or Keywords:
	help = flag to print header
 Outputs:
	typeof = type code from the size array
 Common blocks:
	none
 Procedure:
	Just get the type code from the size array.
 Modification history:
	write, 2 Dec 92, F.K.Knight (knight@ll.mit.edu)

(See /host/bluemoon/usr2/idllib/user_contrib/knight/typeof.pro)

 Name:
	weibull
 Purpose:
	Function to return the value of the Weibull pdf.
 Example:
	beta = 1.	; SHAPE PARAMETER
			;   =1==> exponential distribution
			;   >1==> wear-out type shapes whereby f(T) is zero at
			;   T=gamma, increases as T-->T~, and then decays to 0.
			;   =2==> Rayleigh distribution
	gamma = 0.	; LOCATION PARAMETER
			;   locates the distribution along the abscissa
	eta = 1.	; SCALE PARAMETER
			;   reciprocal of useful life
	T = findgen(100)/10.
	print,weibull(T,beta,gamma,eta)
 Usage:
	pdf = weibull(T[,beta][,gamma][,eta][,/help][,/reliability][,/failurerate])
 Inputs:
	T = abscissa coordinate, scalar or array
 Optional Inputs:
	beta = shape parameter, > 0 (D=1==> exponential distribution)
	eta = scale parameter, > 0 (D=1)
	gamma = location parameter (D=0)
 Keywords:
	help = flag to print header
	/reliability = return only the exponential portion:
	  R = exp(-((T-gamma)/eta)^beta)
	  R has a value of 1 from 0<=T<=gamma 
	  and decreases for T>gamma to zero.
	/failurerate = return only the failure rate portion:
	  lambda = (beta/eta)*((T-gamma)/eta)^(beta-1)
	  lambda is infinity for 0

(See /host/bluemoon/usr2/idllib/user_contrib/knight/weibull.pro)


 

WRGB
[Previous Routine]
[List of Routines]
 Name:
	wrgb
 Purpose:
	Read and display colors from the rgb table---good
	for choosing X-windows colors and browsing for pleasing hues.
 Usage:
	wrgb[,offset=offset][,dim=dim]
 Optional Inputs:
	offset = starting point in the file; there are about 740 entries.
	dim = length of side (in pixels) of a color square
 Outputs:
	Colors are reported to the terminal if the left or middle
	mouse button is pushed.
 Common blocks:
	wrgb = variables that need to be passed between routines
 Procedure:
	Use IDL widgets.  After setup, xmanager runs the show.  The background
	routine (wrgb_bck) runs like rdpix.pro and reports the color at the
	cursor position to the window.  Pushing the left or middle mouse 
	button records the current color at the terminal, again like rdpix.pro.
	Moving the offset slider forces an update of the color table.
	Pushing the done button kills all the widgets.
 Example:
	IDL> wrgb		; starts widget
 Modification history:
	convert xrgb to widget-based wrgb, 30Sep91, FKK
	fix bugs, e.g. cursor,x,y,2 didn't return on cursor motion, 7Oct91, FKK
	save existing color table at start and reset it at end, 29Jan92, FKK
	add help button, 29 Jul 92, FKK
	use a generic file rather then $OPENWINHOME/lib/rgb.txt, 6 Oct 92, FKK 

(See /host/bluemoon/usr2/idllib/user_contrib/knight/wrgb.pro)