SCPEREL.TXT

LBL "SCPEREL" ;print a b for drwg ellipse of isoperim P in S steps
             ;a and b are the ellipse half parameter
             ;Step S  2..100000 in area 0.. 0.636619771 ((2/pi)* P / 4)
             ;
             ;Entry
             ;  S ENTER  P XEQ SCPEREL
             ;Output
             ;  --START-----
             ;  ELLIPSE CALC
             ;  ISOPERIME OF
             ;   16.00000000 ***
             ;   IN
             ;   300.0000000 ***
             ;   STEPS
             ;  X-Y & R-ANG>
             ;   2.546479085 ***   (=X)
             ;   2.546479093 ***   (=Y)
             ;   3.601265264 ***   (=Radius)
             ;   0.785398162 ***   (=Angle in rad)
             ;  X-Y & R-ANG>
             ;   2.537990821 ***
             ;   ...
             ;require a printer or a terminal emulator/pyilper for logging 
             ;put outputs into desmos.com for graphic representation
             ;
             ;R22-23, R 20-21 in BPEREL, R 00-19 are used in PERELS and 3 and 4
             ;
             ;under CC BY SA creative commons 4.0 pascaldagornet at yahoo dot de
             ;
             ;create raw file with "hp41uc.exe /t=SCPEREL.TXT /r /k" or             
             ;create raw file with "rpncomp --raw-output SCPEREL.TXT" and upload
             ;into V41 PC emulator for pyILPER virtual drive  
             ;
             ;change log
             ;2021 10 05 comments modified
             ;2021 10 12 header with decr of input outputs
             ;2021 10 14 less PRA, XROM instead of PRA PRX
             ;
             ;
RAD            
ADV      
"--START-----"
;PRA      
XROM  29,08
"ELLIPSE CALC" 
;PRA     
XROM  29,08       
"ISOPERIME OF" 
;PRA
XROM  29,08
;PRX
XROM  29,20
" IN         "
;PRA
XROM  29,08
STO 20       ;P in R 20 (for later); same R 20 like in BPEREL
X<>Y           
0.636619771  ;2 / PI  
X<>Y
;PRX
XROM  29,20
" STEPS      "
;PRA
XROM  29,08
/
*
4
/
STO 22       ;Step decrement in 22
0.636619771   
RCL 20
*
4
/
STO 23       ;(2 / PI)*P/4   start of calculation
LBL 01       ;main loop
  "X-Y & R-ANG>"
  ;PRA
  XROM  29,08
  ;PRX  ;output x (a)
  XROM  29,20       
  RCL 20
  XEQ "BPEREL"
  ;PRX
  XROM  29,20  ;output x (b)
  RCL 23
  R-P
  ;PRX
  XROM  29,20
  X<>Y
  PI
  2
  /
  X<>Y
  -
  ;PRX
  XROM  29,20
  RCL 22
  ST- 23
  RCL 23
  X>0?
  GOTO 01
DEG
"--END-------"
;PRA
XROM  29,08
RTN
END