## all functions - r

random
```
random(dimension_list)
random_seed, seed

returns an array of random double values with the given
DIMENSION_LIST (nil for a scalar result), uniformly distributed
on the interval from 0.0 to 1.0.
The algorithm is from Press and Teukolsky, Computers in Physics,
vol. 6, no. 5, Sep/Oct 1992 (ran2).  They offer a reward of \$1000
to anyone who can exhibit a statistical test that this random
number generator fails in a "non-trivial" way.
The random_seed call reinitializes the random number sequence;
SEED should be between 0.0 and 1.0 non-inclusive; if SEED is
omitted, nil, or out of range, the sequence is reinitialized as
when Yorick starts.
The numbers are actually at the centers of 2147483562 equal width
bins on the interval [0,1].  Although only these 2 billion numbers
are possible, the period of the generator is roughly 2.3e18.
Builtin function, documented at i0/std.i   line 758

```

random_ipq
```
random_ipq(ipq_model, dimlist)

returns an array of double values with the given DIMLIST (see array
function, nil for a scalar result).  The numbers are distributed
according to a piecewise linear function (possibly with power law
or exponential tails) specified by the IPQ_MODEL.  The "IPQ" stands
for "inverse piecewise quadratic", which the type of function
required to transform a uniform random deviate into the piecewise
linear distribution.  Use the ipq_setup function to compute
IPQ_MODEL.
Interpreted function, defined at i/random.i   line 179

```

random_n
```
random_n(dimlist)

returns an array of normally distributed random double values with
the given DIMLIST (see array function, nil for a scalar result).
The mean is 0.0 and the standard deviation is 1.0.
The algorithm follows the Box-Muller method (see Numerical Recipes
by Press et al.).
Interpreted function, defined at i/random.i   line 130

```

random_rej
```
random_rej(target_dist, ipq_model, dimlist)
or random_rej(target_dist, bounding_dist, bounding_rand, dimlist)

returns an array of double values with the given DIMLIST (see array
function, nil for a scalar result).  The numbers are distributed
according to the TARGET_DIST function:
func target_dist(x)
returning u(x)>=0 of same number and dimensionality as x, normalized
so that the integral of target_dist(x) from -infinity to +infinity
is 1.0.  The BOUNDING_DIST function must have the same calling
sequence as TARGET_DIST:
func bounding_dist(x)
returning b(x)>=u(x) everywhere.  Since u(x) is normalized, the
integral of b(x) must be >=1.0.  Finally, BOUNDING_RAND is a
function which converts an array of uniformly distributed random
numbers on (0,1) -- as returned by random -- into an array
distributed according to BOUNDING_DIST:
func bounding_rand(uniform_x_01)
Mathematically, BOUNDING_RAND is the inverse of the integral of
BOUNDING_DIST from -infinity to x, with its input scaled to (0,1).
If BOUNDING_DIST is not a function, then it must be an IPQ_MODEL
returned by the ipq_setup function.  In this case BOUNDING_RAND is
omitted -- ipq_compute will be used automatically.
Interpreted function, defined at i/random.i   line 199

```

random_seed
```
random_seed

Builtin function, documented at i0/std.i   line 758

```
SEE random

random_u
```
random_u(a, b, dimlist)

return uniformly distributed random numbers between A and B.
(Will never exactly equal A or B.)  The DIMLIST is as for the
array function.  Same as (b-a)*random(dimlist)+a.  If A==0,
you are better off just writing B*random(dimlist).
Interpreted function, defined at i/random.i   line 113

```

random_x
```
random_x(dimlist)

same as random(DIMLIST), except that random_x calls random
twice at each point, to avoid the defect that random only
can produce about 2.e9 numbers on the interval (0.,1.) (see
random for an explanation of these bins).
You may set random=random_x to get these "better" random
numbers in every call to random.
Unlike random, there is a chance in 1.e15 or so that random_x
may return exactly 1.0 or 0.0 (the latter may not be possible
with IEEE standard arithmetic, while the former apparently is).
Since cosmic rays are far more likely, you may as well not
patterns may still be more likely than others, but the 0.5e-9
wide bins of random will be absent.
Interpreted function, defined at i/random.i   line 74

```

randomize
```
randomize
randomize()

set the seed for random "randomly" (based on the timer clock
and the current state of random).  As a function, returns the
value of the seed passed to random_seed.
Interpreted function, defined at i0/std.i   line 780

```

range
```
range, ymin, ymax

sets the y-axis plot limits in the current coordinate system to
YMIN, YMAX, which may be nil or omitted to leave the corresponding
limit unchanged, a number to fix the corresponding limit to a
specified value, or the string "e" to make the corresponding limit
take on the extreme value of the currently displayed data.
Use    limits, xmin, xmin
to accomplish the same function for the x-axis plot limits.
Interpreted function, defined at i0/graph.i   line 836

```

range3
```
range3, zmin,zmax

Set the 3D axis z limits for use with the cage.
Use keyword aspect=[ax,ay,az] to set the aspect ratios of the
cage to ax:ay:az -- that is, the ratios of the lengths of the
cage axes will become ax:ay:az.
Interpreted function, defined at i/pl3d.i   line 221

```

raw_not_cdf
```
raw_not_cdf

Interpreted function, defined at i/netcdf.i   line 57

```

raw_style
```
#include "style.i"

alternatives to the style= keyword of the window command which
allow the interpreter to set or get all the details of the
window style.  Include "style.i" and read the help for get_style.
Builtin function, documented at i0/graph.i   line 1515

```

rdfile
```
rdfile(f)
or rdfile(f, nmax)

reads all remaining lines (or at most NMAX lines) from file F.
If NMAX is omitted, it defaults to 2^20 lines (about a million).
The result is an array of strings, one per line of F.
Interpreted function, defined at i0/std.i   line 2110

```

rdline
```
rdline(f)
or rdline(f, n, prompt= pstring)

returns next line from stream F (stdin if F nil).  If N is non-nil,
returns a string array containing the next N lines of F.  If
end-of-file occurs, rdline returns nil strings.  If F is nil,
uses the PSTRING to prompt for input (default "read> ").
Builtin function, documented at i0/std.i   line 2100

```

```
n= read(f, format=fstring, obj1, obj2, ...)
or n= read(prompt= pstring, format=fstring, obj1, obj2, ...)
or n= sread(source, format=fstring, obj1, obj2, ...)

reads text from I/O stream F (1st form), or from the keyboard (2nd
form), or from the string or string array SOURCE (3rd form),
interprets it according to the optional FSTRING, and uses that
interpretation to assign values to OBJ1, OBJ2, ...  If the input
is taken from the keyboard, the optional prompt PSTRING (default
"read> ") is printed before each line is read.  The Yorick write
function does not interact with the read function -- writes are
always to end-of-file, and do not affect the sequence of lines
returned by read.  The backup (and bookmark) function is the
only way to change the sequence of lines returned by read.
There must be one non-supressed conversion specifier (see below)
in FSTRING for each OBJ to be read; the type of the conversion
specifier must generally match the type of the OBJ.  That is,
an integer OBJ requires an integer specifier (d, i, o, u, or x)
in FSTRING, a real OBJ requires a real specifier (e, f, or g),
and a string OBJ requires a string specifier (s or []).  An OBJ
may not be complex, a pointer, a structure instance, or any non-
array Yorick object.  If FSTRING is not supplied, or if it has
fewer conversion specifiers than the number of OBJ arguments,
then Yorick supplies default specifiers ("%ld" for integers,
"%lg" for reals, and "%s" for strings).  If FSTRING contains more
specifiers than there are OBJ arguments, the part of FSTRING
beginning with the first specifier with no OBJ is ignored.
The OBJ may be scalar or arrays, but the dimensions of every OBJ
must be identical.  If the OBJ are arrays, Yorick behaves as
if the read were called in a loop numberof(OBJ1) times, filling
one array element of each of the OBJ according to FSTRING on
each pass through the loop.  (Note that this behavior includes
the case of reading columns of numbers by a single call to read.)
The return value N is the total number of scalar assignments
which were made as a result of this call.  (If there were 4
OBJ arguments, and each was an array with 17 elements, a return
value of N==35 would mean the following:  The first 8 elements
of OBJ1, OBJ2, OBJ3, and OBJ4 were read, and the 9th element of
elements of the OBJ which were not read to zero -- hence,
independent of the returned N, the all of the old data in the
OBJ arguments is overwritten.
(1) all elements of all OBJ have been filled, or (2) end-of-file
(or end of SOURCE for sread) is reached ("input failure"), or
(3) part of FSTRING or a conversion specifier supplied by
default fails to match the source text ("matching failure").
The FSTRING is composed of a series of "directives" which are
(1) whitespace -- means to skip any amount of whitespace in the
source text
(2) characters other than whitespace and % -- must match the
characters in the source text exactly, or matching failure
occurs and the read operation stops
(3) conversion specifiers beginning with % and ending with a
character specifying the type of conversion -- optionally
skip whitespace, then convert as many characters as
continue to "look like" the conversion type, possibly
producing a matching failure
The conversion specifier is of the form %*WSC, where:
is either the character '*' or not present
A specifier beginning with %* does not correspond to any of
the OBJ; the converted value will be discarded.
W is either a positive decimal integer specifying the maximum
field width (not including any skipped leading whitespace),
or not present if any number of characters up to end-of-line
is acceptable.
S is either one of the characters 'h', 'l', or 'L', or not
present.  Yorick allows this for compatibility with the C
library functions, but ignores it.
C is a character specifying the type of conversion:
d   - decimal integer
o   - octal integer
u   - unsigned decimal integer (same as d for Yorick)
x, X            - hex integer
e, f, g, E, G   - floating point real
s   - string of non-whitespace characters
[xxx]   - (xxx is any sequence of characters) longest string
of characters matching those in the list
[^xxx]  - longest string of characters NOT matching those in
the list (this is how you can extend %s to be
delimited by something other than whitespace)
%   - the ordinary % character; complete conversion
specification must be "%%"
The read function is modeled on the ANSI standard C library
fscanf and sscanf functions, but differs in several respects:
(1) Yorick's read cannot handle the %c, %p, or %n conversion
specifiers in FSTRING.
(2) Yorick's read never results in a portion of a line
being read -- any unused part of a line is simply discarded
(end FSTRING with "%[^\n]" if you want to save the trailing
part of an input line).
(3) As a side effect of (2), there are some differences between
fscanf and Yorick's read in how whitespace extending across
newlines is handled.
Builtin function, documented at i0/std.i   line 1994

```

```

raw routine to set the binary data structure of FILE according
to the text description in the Contents Log file CLOG_NAME.
Builtin function, documented at i0/std.i   line 2649

```

```

Interpreted function, defined at i/ylmdec.i   line 372

```

```

Interpreted function, defined at i/ylmdec.i   line 259

```

```
read_style, file, landscape, systems, legends, clegends

read a Gist style sheet (.gs file), and return the data
structures as described in the get_style function.  The FILE
can be a filename or a text file stream.
Interpreted function, defined at i/style.i   line 312

```

recover_file
```
recover_file, filename
or recover_file, filename, clogfile

writes the descriptive information at the end of a corrupted
binary file FILENAME from its Contents Log file CLOGFILE, which
is FILENAME+"L" by default.
Interpreted function, defined at i0/std.i   line 2655

```

redraw
```
redraw

redraws the X window associated with the current graphics window.
Builtin function, documented at i0/graph.i   line 334

```

reform
```
reform(x, dimlist)

returns array X reshaped according to dimension list DIMLIST.
Interpreted function, defined at i0/std.i   line 301

```

reg_track
```
c= reg_track(x, y, z, rays, s)

track RAYS through regular mesh defined by the 1D coordinate
arrays X, Y, and Z.  Return values S and C are as for
hex5_track, where the mesh is numberof(X) by numberof(Y) by
numberof(Z).
Builtin function, documented at i0/hex.i   line 85

```

remove
```
remove

Builtin function, documented at i0/std.i   line 1986

```
SEE rename

rename
```
rename, old_filename, new_filename
remove filename

rename or remove a file.
Builtin function, documented at i0/std.i   line 1986

```

require
```
require

Builtin function, documented at i0/std.i   line 2254

```
SEE include

reset
```
reset

Interpreted function, defined at i/demo1.i   line 37

```

reset_options
```
reset_options

resets all options for the streak, snap, and streak_save functions
to their default values.
Interpreted function, defined at i0/drat.i   line 856

```

reshape
```
or reshape, reference, type, dimension_list
or reshape, reference

The REFERENCE must be an unadorned variable, not an expression;
reshape sets this variable to an LValue at the specified ADDRESS
with the specified TYPE and DIMENSION_LIST.  (See the array
function documentation for acceptable DIMENSION_LIST formats.)
If ADDRESS is an integer (e.g.- a long), the programmer is
responsible for assuring that the data at ADDRESS is valid.
If ADDRESS is a (Yorick) pointer, Yorick will assure that the
data pointed to will not be discarded, and the reshape will
fail if TYPE and DIMENSION_LIST extend beyond the pointee
bounds.  In the second form, ADDRESS is taken to be &REFERENCE;
that is, the TYPE and DIMENSION_LIST of the variable are changed
without doing any type conversion.  In the third form, REFERENCE
is set to nil ([]).  (Simple redefinition will not work on a
variable defined using reshape.)
WARNING: There are almost no situations for which reshape is
the correct operation.  Use reform instead.
Builtin function, documented at i0/std.i   line 278

```

restore
```
restore

Builtin function, documented at i0/std.i   line 3080

```
SEE save

restore3
```
restore3, view

Restore a previously saved 3D viewing transformation and lighting.
If VIEW is nil, rotate object to viewer's coordinate system.
Interpreted function, defined at i/pl3d.i   line 242

```

```

is an optional hook function which is called after any change to the
mesh (e.g.- by dragging points) has been made.  If it is defined, it
may modify the external variables rez_rt and rez_zt.  This hook can
be used, for example, to force points along some k or l line to lie
along a symmetry line.
Builtin function, documented at i/rezone.i   line 130

```

rez_all
```
rez_all

Click on [Drag Points] to drag points around with the mouse with
rez_drag.
Click on [Adjust Line] to adjust points along a line segment with
Click on the [Undo] button to undo the previous change.
Click on the [Redo] button to redo the previous undo.
When you are finished moving points around, click on [OK].
Click on [Escape] to exit with a non-zero return value.
Click on [Zoom or Pan] to change the plot limits (see rez_zoom).
Click on [Set Styles] to change the line styles or colors (see
rez_style).
Interpreted function, defined at i/rezone.i   line 423

```

rez_chk_palette
```
rez_chk_palette

Interpreted function, defined at i/rezone.i   line 98

```

rez_color
```
rez_color

Builtin function, documented at i/rezone.i   line 39

```
SEE rez_kstyle

rez_ding
```
rez_ding

Interpreted function, defined at i/rezone.i   line 1517

```

rez_drag
```
rez_drag

Allow points in the rezone mesh to be dragged around with
the mouse.  Press mouse button near a vertex, move mouse
to desired position of that vertex, and release button.
If the point where you click is less than twice the distance to the
second closest point than to the nearest point, the point will not
be moved (you will hear a beep when you release the button).
Click on the [Undo] button to undo the previous move; you can undo
up to 100 previous moves by successive [Undo] clicks.
When you are finished moving points around, click on [OK].
Click on [Zoom or Pan] to change the plot limits (see rez_zoom).
Click on [Set Styles] to change the line styles or colors (see
rez_style).
Interpreted function, defined at i/rezone.i   line 532

```

rez_find
```
rez_find

Interpreted function, defined at i/rezone.i   line 1493

```

rez_getrz
```
rez_getrz

Interpreted function, defined at i/rezone.i   line 1451

```

rez_getvar
```
rez_getvar

Interpreted function, defined at i/rezone.i   line 1506

```

rez_kstyle
```
rez_kstyle, rez_lstyle, rez_color

is a vector of three longs:  [type,width,color]
type MUST be 1, 2, 3, 4, or 5,
width MUST be 1, 2, 3, 4, 5, 6, 7, or 8,
and color MUST be -1, -2, -3, -4, -5, -6, -7, -8, -9, or -10
Either or both parameters may be set before or after including
rez.i; by default:
rez_kstyle= [4, 1, -2]    (dashdot, thin, foreground color)
rez_lstyle= [1, 1, -2]    (solid, thin, foreground color)
To distinguish K and L by color instead of type, try:
rez_kstyle= [1, 1, -7]    (dashdot, thin, blue)
rez_lstyle= [1, 1, -5]    (solid, thin, red)
If the variable rez_color is true (non-nil and non-zero) when
this file is included, then these will be the default.
Builtin function, documented at i/rezone.i   line 39

```

```

Adjust the points along a logical line segment PQ:
Click on [Set P] or [Set Q] to set the endpoints of the segment.
When P and Q have been set, click [OK]; this button will
read [Cancel] if P and Q do not have either the same K or the
same L index.
Click on [Smooth] to smooth the points along PQ.
Click on [Equal Space] to make the points along PQ equally spaced.
This forces PQ to be a straight line.
Drag any point between P and Q to get equal ratio spacing of all
the points between P and Q.  This also forces PQ to be a straight
line; if PQ is initially curved, you may want to click on
[Equal Space] before you attempt to drag points.
Click on the [Undo] button to undo the previous adjustment; you can
undo up to 20 previous adjustments by successive [Undo] clicks.
When you are finished adjusting lines, click on [OK].
Click on [Zoom or Pan] to change the plot limits (see rez_zoom).
Click on [Set Styles] to change the line styles or colors (see
rez_style).
Hint:
You can select a center point as the second point during
rez_ladj.  When you do this, the K (or L) value of this second
point will be the same as that of the first point --
otherwise there is no way to distinguish among all of the
logical points at the center.
Interpreted function, defined at i/rezone.i   line 615

```

```

If non-nil, filename to be included immediately after rez.i.
This file can be used to set personalized default values for the
many parameters.
Builtin function, documented at i/rezone.i   line 30

```

rez_lstyle
```
rez_lstyle

Builtin function, documented at i/rezone.i   line 39

```
SEE rez_kstyle

rez_mark
```
rez_mark

Causes rezone functions to mark bowtied or chevroned (boomeranged)
zones when the mesh is plotted.  MUST have one of the following values:
0 to not mark bowtied or chevroned zones
1 to put a B at the center of the positive triangle of bowtied zones
2 to put a C at the center of the larger wing of chevroned zones
3 to mark both bowtied and chevroned zones
By default, rez_mark is 3; you may set it to a different value
either before or after including rez.i.
Builtin function, documented at i/rezone.i   line 66

```

rez_mesh
```
rez_mesh, rt, zt, ireg

-or- rez_mesh, rt, zt
-or- rez_mesh, zfile
set mesh for rez_... commands.  If ZFILE is specified, it must be a
binary file containing variables RT, ZT, and (optionally) IREG.
Interpreted function, defined at i/rezone.i   line 1373

```

rez_next
```
rez_next

zoom in on next bowtied (or chevroned) zone (after rez_mesh).
With numeric argument, zooms to that bowtie (or chevron).  With
numeric argument 0, zooms to current bowtie (or chevron).
Interpreted function, defined at i/rezone.i   line 1410

```

rez_palette
```
rez_palette

3-by-ncolors array used as a palette when rez_regs region coloring
is set.  The index in rez_regs is the second index into rez_palette.
The length 3 first index is [r,g,b].
The default is 15 pastels.
Builtin function, documented at i/rezone.i   line 84

```

rez_plm
```
rez_plm

Interpreted function, defined at i/rezone.i   line 140

```

rez_prev
```
rez_prev

zoom in on previous bowtied (or chevroned) zone (after rez_mesh).
Interpreted function, defined at i/rezone.i   line 1442

```

rez_ptexist
```
rez_ptexist

Interpreted function, defined at i/rezone.i   line 1474

```

rez_qrt
```
rez_qrt, rez_qzt, rez_qireg

are the names of the mesh variables for rez_mesh, "rt", "zt", and
"ireg" by default.  Note that ireg is optional.
Builtin function, documented at i/rezone.i   line 1364

```

```

Adjust the points in a logical rectangle PQRS:
Click on [Set P] or [Set R] to set the endpoints of the segment.
When P and R have been set, click [OK]; this button will
read [Cancel] if P and R have the same K or the same L index.
Click on a point on any edge of PQRS (but not one of the corners)
to copy the spacings on that edge throughout the entire region.
All of the lines of the same type (K-line or L-line) as the edge
you clicked on will become straight lines.
Click on [Smooth] to smooth the points interior to PQRS.
Click on [Smooth 4] to perform the smooth operation four times.
Click on the [Undo] button to undo the previous adjustment; you can
undo up to 10 previous adjustments by successive [Undo] clicks.
When you are finished adjusting regions, click on [OK].
Click on [Zoom or Pan] to change the plot limits (see rez_zoom).
Click on [Set Styles] to change the line styles or colors (see
rez_style).
Hint:
You can select a center point as the second point during
rez_radj.  When you do this, the K (or L) value of this second
point will be the same as that of the first point --
otherwise there is no way to distinguish among all of the
logical points at the center.  The center point will be labeled
Q instead of R as usual, and you will need to choose a third
point (S) to complete the rectangle PQRS.
Interpreted function, defined at i/rezone.i   line 865

```

rez_range
```
rez_range

Interpreted function, defined at i/rezone.i   line 1515

```

rez_regs
```
rez_regs

is a vector of region numbers which are to be drawn in the colors
specified in rez_palette.  Thus:
rez_regs= [3,5]
causes regions 3 and 5 to be drawn in colors.  All other regions have
white backgrounds.  Hilighting too many regions in this way may slow
down the redraws unacceptably.  To highlight all regions, use:
rez_regs= indgen(max(rez_ireg))
This won't work on monochrome monitors, of course.
The default is rez_regs=[].
Builtin function, documented at i/rezone.i   line 116

```

rez_solve
```
rez_solve

Interpreted function, defined at i/rezone.i   line 1522

```

rez_style
```
rez_style

Interpreted function, defined at i/rezone.i   line 1258

```

rez_toggle
```
rez_toggle

Interpreted function, defined at i/rezone.i   line 261

```

rez_zoom
```
rez_zoom

Change limits after setting rez_mesh.
There are two modes of operation:
(1) P-mode:
Click on a point to magnify or demagnify about that point.
Drag the point to move it to a different position in the
viewport.  The left button zooms in (magnifies by 1.5), the
right button zooms out (demagnifies by 1.5), and the middle
button pans (no magnification change).  If you click just
below or just above the tick marks, only the x coordinate
is changed; clicking just to the left or just to the right
of the viewport changes only the y coordinate.
(2) R-mode:
Left drag out a rectangle to set the limits to that rectangle.
Right drag out a rectangle to cram the entire current viewport
into that rectangle (an analog to zooming out).
Middle drag to pan as in P-mode (the rubber band rectangle is
meaningless in this case).
Click the [R-mode] (or [P-mode]) button to change modes.
Click the [OK] button when you are satisfied with the limits.
Click the [Undo] button to remove the effect of the previous
zoom-click.  Up to 100 successive undo operations are allowed.
Click the [Polar] button to toggle polar coordinates.  The
vertical axis will be theta, and the horizontal axis radius.
The polar coordinate origin will be at (zt,rt) = (0,0).
Click the [Next], [Prev], or [First] buttons to focus in on
zones which are bowtied or chevroned.  These zones are marked
by a B or a C, respectively (if rez_mark is set).
Interpreted function, defined at i/rezone.i   line 1113

```

rezone
```
rezone, filename

-or- rezone
Invoke the mouse-driven rezoner.  Input is taken from variables
rt, zt, and ireg in the file FILENAME (which is prompted for if
omitted).  Output is written to a different file as rt, zt, and
ireg.  The output file also contains copies rez_rt, rez_zt, and
rez_ireg in case the mesh under a different name is desirable,
as well as rez_rt0, rez_zt0, and rez_ireg0, which are the original
mesh.
If you click on [Escape], you may continue rezoning where you left
off by typing   rezone   with no arguments.
When you are finished, click [OK] to write the output file.
Use [Zoom or Pan] and [Set Styles] to change the plot limits or
line colors and styles.  The [Zoom or Pan] screen has buttons which
"warp" you to each bowtied or chevroned "problem" zone, as well as
a button to toggle between rectangular and polar coordinates.
Click [Drag Points] to drag points one at a time with the mouse.
Click [Adjust Line] to smooth the points on logical line segments.
You first click on the endpoints P and Q, then click a button to
smooth or equal space the poionts between P and Q, or drag any
point between P and Q to establish equal ratio zones ("ER" operation).
Click [Adjust Region] to smooth the points in logically rectangular
regions.  You first click on the opposite corners P and R of the
rectangle PQRS, then click a button to smooth the interior points,
or click on a point on one of the four edges to transfer the spacing
on that edge throughout the region PQRS ("EQ" operation).
The [Undo] (or [Redo]) button removes the effect of the most
Hints:
(0) After [Escape], the current mesh is in the variables
rez_zt, rez_rt, and rez_ireg.  You can change these
variables "by hand" before restarting rezone to make
(1) Switch to polar coordinates during an [Adjust Line] or
[Adjust Region] in order to get points to lie along a
circular arc.  If your center point is not (0,0), you
will need to [Escape] and subtract your center point
from the rez_zt and rez_rt variables yourself, then
[Escape] a second time to restore the proper coordinates
before you write the output file.
(2) You can select a center point as the second point during
K (or L) value of this second point will be the same as
that of the first point -- otherwise there is no way to
distinguish among all of the logical points at the center.
In an [Adjust Region], the center point will be labeled
Q instead of R as usual, and you will need to choose a
third point (S) to complete the rectangle PQRS.
(3) If you set the variable rez_color=1 before you include
rezone.i, you will get K lines and L lines drawn in different
colors instead of the default (which is K lines dashdot and
L lines solid).
(4) If you have a color monitor, you can set rez_regs before
invoking rezone in order to highlight a list of regions.
The ALL keyword will be passed to the nbow function, which will
not be called if the QUIET keyword is non-nil and non-zero.  By
default, a short summary of bowtied and chevroned zones is printed.
If you need help on how to use one of the screens, try getting
help on the appropriate on of these see-also topics, e.g.-
help, rez_style
to get help on the [Set Styles] screen.
Interpreted function, defined at i/rezone.i   line 294

```

```

Read contents of current graphics window, or of graphics window N.
RGB is a 3xNXxNY array of char where NXxNY is the current shape of
the window in pixels.  RGB(1,,) is the red component, RGB(2,,) is
the green component, and RGB(3,,) is the blue component, with 0
black and 255 full intensity.  RGB(,,1) is the top row of the
window, RGB(,,2) the second row, and so on to RGB(,,0), which is
the bottom row.  (So RGB(,,::-1) to pli redraws a copy.)
Builtin function, documented at i0/graph.i   line 1452

```

rk4
```
y_at_x_plus_dx= rk4(y,dydx, x,dx, derivative)

takes a single 4th order Runge-Kutta step from X to X+DX.
DERIVATIVE(y,x) is a function returning dydx; the input DYDX
is DERIVATIVE(y,x) at the input (X,Y).  This fourth evaluation
of DERIVATIVE must be performed by the caller of rk4.
Interpreted function, defined at i/rkutta.i   line 233

```

rk_integrate
```
y= rk_integrate(derivative, y1, x, epsilon, dx1)

integrates dydx= DERIVATIVE(y,x) beginning at (X(1),Y1) and
going to X(0) with fractional error EPSILON.  The result is
the value of y at each value in the list X.  If non-nil, DX1
will be used as initial guess for the first step size.
Otherwise, X(2)-X(1) will be the first step size guess.
The list of X values must be monotone -- strictly increasing
or strictly decreasing; the Runge-Kutta step sizes are selected
adaptively until the next X value would be passed, when the
step size is adjusted to complete the step exactly.
The external variable rk_maxits (default 10000) is the
maximum number of steps rk_integrate will take.
If a function rk_yscale(y,dydx,x,dx) exists, it is used
to compute an appropriate yscale to give the EPSILON error
criterion meaning.  Otherwise, yscale is taken to be:
abs(y)+abs(dydx*dx)+1.e-30
Based on odeint from Numerical Recipes (Press, et.al.).
If the function you are trying to integrate is very
smooth, and your X values are fairly far apart, bs_integrate
may work better than rk_integrate.
Interpreted function, defined at i/rkutta.i   line 14

```

rk_store
```
rk_store

Interpreted function, defined at i/rkutta.i   line 163

```

rkdumb
```
y_of_x= rkdumb(derivative, y0,x0, x1,nsteps)

integrates dydx= DERIVATIVE(y,x) beginning at (X0,Y0) and
going to X1 in NSTEPS 4th order Runge-Kutta steps.  The
result is dimsof(Y0)-by-(NSTEPS+1) values of y at the points
span(X0, X1, NSTEPS+1).
If the nosave= keyword is non-zero, the returned value will
simply be the final y value.
Interpreted function, defined at i/rkutta.i   line 184

```

rkqc
```
rkqc

Interpreted function, defined at i/rkutta.i   line 205

```

rkutta
```
y1= rkutta(derivative, y0,x0, x1,epsilon, dx0)

integrates dydx= DERIVATIVE(y,x) beginning at (X0,Y0) and
going to X1 with fractional error EPSILON.  The result is
the value of y at X1.  DX0 will be used as the initial guess
for a step size.
If the external variable rk_nstore is >0, rk_y and rk_x
will contain up to rk_nstore intermediate values after the
call to rkutta.  Consider using rk_integrate if you need
this feature; using rk_nstore gives you the results at
intermediate values which will tend to be closer where
the Runge-Kutta step size was smaller, while rk_integrate
forces you to specify precisely which x values you want.
The external variable rk_maxits (default 10000) is the
maximum number of steps rkutta will take.  The variable
rk_minstep (default 0.0) is the minimum step size.  The
variable rk_maxstep (default 1.e35) is the maximum step
size, which you may need if you are storing intermediate
values (particularly with bstoer).
If a function rk_yscale(y,dydx,x,dx) exists, it is used
to compute an appropriate yscale to give the EPSILON error
criterion meaning.  Otherwise, yscale is taken to be:
abs(y)+abs(dydx*dx)+1.e-30
Based on odeint from Numerical Recipes (Press, et.al.).
If the function you are trying to integrate is very
smooth, bstoer will probably work better than rkutta.
Interpreted function, defined at i/rkutta.i   line 52

```

rmdir
```
rmdir

Builtin function, documented at i0/std.i   line 2478

```
SEE mkdir

roll
```
roll(x, ljoff, rjoff)
or roll, x, ljoff, rjoff
or roll(x)
or roll, x

"rolls" selected dimensions of the array X.  The roll offsets
LJOFF and RJOFF (both optional) work in the same fashion as the
LJDIR and RJDIR arguments to the fft function:
A scalar LJDIR (and nil RJDIR) rolls all dimensions of X by
the specified offset.
Otherwise, the elements of the LJDIR vector [ljoff1, ljoff2, ...]
are used as the roll offsets for the first, second, etc.
dimensions of X.
Similarly, the elements of the RJDIR vector [..., rjoff1, rjoff0]
are matched to the final dimensions of X, so the next to last
dimension is rolled by rjoff1 and the last dimension by rjoff0.
As a special case (mostly for use with the fft function), if
both LJDIR and RJDIR are nil, every dimension is rolled by
half of its length.  Thus,
roll(x)
it equivalent to
roll(x, dimsof(x)(2:0)/2)
The result of the roll function is complex if X is complex, otherwise
double (i.e.- any other array type is promoted to type double).  If
roll is invoked as a subroutine, the operation is performed in place.
Interpreted function, defined at i0/fft.i   line 254

```

romberg
```
integral= romberg(function, a, b)
or integral= romberg(function, a, b, epsilon)

returns the integral of FUNCTION(x) from A to B.  If EPSILON is
given, Simpson's rule is refined until that fractional accuracy
is obtained.  EPSILON defaults to 1.e-6.
If the notvector= keyword is supplied and non-zero, then FUNCTION
may not be called with a list of x values to return a list of
results.  By default, FUNCTION is assumed to be a vector function.
If the function is not very smooth, simpson may work better.
Interpreted function, defined at i/romberg.i   line 10

```

rot3
```
rot3, xa,ya,za

rotate the current 3D plot by XA about viewer's x-axis,
Interpreted function, defined at i/pl3d.i   line 57

```

rotext
```
plt, rotext(text,path), x, y

return TEXT string as is (PATH=0), reversed (PATH=1), reversed and
with a '\n' between each character, or with '\n' between characters
(PATH=3).  When plotted, these strings correspond to the original
meaning of the text path= keyword.  That is, successive characters
will appear to the right, left, up, or down according to whether
PATH is 0, 1, 2, or 3
Interpreted function, defined at i/txpath.i   line 12

```

rzextr
```
rzextr

Interpreted function, defined at i/rkutta.i   line 338

```