Table of contents
CSPICE_WNFETD fetches a particular interval from
a double precision window.
Given:
window the scalar window containing zero or more intervals.
help, window
STRUCT = cspice_celld(2*N)
'window' must be created as a window structure via a
cspice_celld call.
n the scalar integer index of a particular interval within
'window'.
help, n
LONG = Scalar
Indices range from 0 to N-1, where N is the number of intervals
in the window.
the call:
cspice_wnfetd, window, n, left, right
returns:
left,
right the scalar, double precision left and right endpoints of the 'n'
interval in the input 'window'.
help, left
DOUBLE = Scalar
help, right
DOUBLE = Scalar
None.
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.
1) Given a SPICE window of cardinality 6, fetch the left and right
endpoints of each of its 3 interval intervals.
Example code begins here.
PRO wnfetd_ex1
;;
;; Create a cell containing a double
;; precision 6-vector.
;;
win1 = cspice_celld( 6 )
;;
;; Define a window with three intervals.
;;
darray = [ [ 1.d, 3.0], [ 7.0, 11.0], [23.0, 27.0] ]
;;
;; Add the window data to the cell.
;;
for i=0,2 do begin
cspice_wninsd, darray[0,i], darray[1,i], win1
endfor
;;
;; Calculate the number of intervals in the
;; return window 'win1'.
;;
no_intervals = cspice_wncard(win1)
;;
;; Output the intervals.
;;
print, "Window contents:"
for i= 0, (no_intervals -1 ) do begin
cspice_wnfetd, win1, i, left, right
print, left, right
endfor
END
When this program was executed on a Mac/Intel/IDL8.x/64-bit
platform, the output was:
Window contents:
1.0000000 3.0000000
7.0000000 11.000000
23.000000 27.000000
The user must create any needed window structures with
cspice_celld prior to use regardless of whether the routine
uses the window as input or returns it as output.
1) If `n' is less than one, the error SPICE(NOINTERVAL) is
signaled by a routine in the call tree of this routine.
2) If the interval does not exist, i.e. n > cspice_card(window)/2, the
error SPICE(NOINTERVAL) is signaled by a routine in the call
tree of this routine.
3) The cardinality of the input `window' must be even. Left
endpoints of stored intervals must be strictly greater than
preceding right endpoints. Right endpoints must be greater
than or equal to corresponding left endpoints. Invalid window
data are not diagnosed by this routine and may lead to
unpredictable results.
4) If any of the input arguments, `window' or `n', is undefined,
an error is signaled by the IDL error handling system.
5) If any of the input arguments, `window' or `n', is not of the
expected type, or it does not have the expected dimensions and
size, an error is signaled by the Icy interface.
6) If any of the output arguments, `left' or `right', is not a
named variable, an error is signaled by the Icy interface.
None.
None.
ICY.REQ
CELLS.REQ
WINDOWS.REQ
None.
J. Diaz del Rio (ODC Space)
E.D. Wright (JPL)
-Icy Version 1.0.3, 17-JUN-2021 (JDR)
Edited the header to comply with NAIF standard. Added
example's problem statement.
Added -Parameters, -Exceptions, -Files, -Restrictions,
-Literature_References and -Author_and_Institution sections.
Removed reference to the routine's corresponding CSPICE header from
-Abstract section.
Added arguments' type and size information in the -I/O section.
-Icy Version 1.0.2, 26-NOV-2007 (EDW)
Implemented use of cspice_wncard function to return
window cardinality.
-Icy Version 1.0.1, 12-SEP-2006 (EDW)
Correct Required Reading citation cell.req to cells.req.
-Icy Version 1.0.0, 08-AUG-2004 (EDW)
fetch an interval from a d.p. window
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