Newbie questions

[Arthur Gomide]

My solution to ATAN2, in the 80, when I was using a TRS-80 Model III
For extended-precision values, make the necessary changes.

[color=000000]120 R1[/color][color=8000FF]=[/color][color=000000]57.29578!
    [/color][color=007F00]'
    ' SE contains delta sin
    ' SN contains delta cos
    ' ATAN2 returns in X
    '
[/color][color=000000]1910 [/color][color=0000C0]IF [/color][color=000000]SN[/color][color=8000FF]=[/color][color=000000]0 [/color][color=0000C0]THEN [/color][color=000000]X[/color][color=8000FF]=[/color][color=000000]90[/color][color=8000FF]-([/color][color=000000]SE&lt[/color][color=8000FF];[/color][color=000000]0[/color][color=8000FF])*[/color][color=000000]90 [/color][color=0000C0]ELSE [/color][color=000000]X[/color][color=8000FF]=[/color][color=0000C0]ATN[/color][color=8000FF]([/color][color=000000]SE[/color][color=8000FF]/[/color][color=000000]SN[/color][color=8000FF])*[/color][color=000000]R1[/color][color=8000FF]-([/color][color=000000]SN&lt[/color][color=8000FF];[/color][color=000000]0[/color][color=8000FF])*[/color][color=000000]180[/color][color=8000FF]:[/color][color=0000C0]IF [/color][color=000000]X&lt[/color][color=8000FF];[/color][color=000000]0 [/color][color=0000C0]THEN [/color][color=000000]X[/color][color=8000FF]=[/color][color=000000]X[/color][color=8000FF]+[/color][color=000000]360
[/color]

Test code:

[color=0000C0]#COMPILE EXE
#DIM ALL

FUNCTION PBMAIN [/color][color=8000FF]() [/color][color=0000C0]AS LONG

    LOCAL [/color][color=000000]R1[/color][color=8000FF], [/color][color=000000]SE[/color][color=8000FF], [/color][color=000000]SN[/color][color=8000FF], [/color][color=000000]X [/color][color=0000C0]AS SINGLE

[/color][color=000000]120 R1[/color][color=8000FF]=[/color][color=000000]57.29578!
1200 SE[/color][color=8000FF]= [/color][color=000000]0[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]= [/color][color=000000]0[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE= 0:SN= 0: ATAN2 should be   0" [/color][color=000000]X [/color][color=007F00]'prints 0
[/color][color=000000]1210 SE[/color][color=8000FF]= [/color][color=000000]0[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]= [/color][color=000000]1[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE= 0:SN= 1: ATAN2 should be   0" [/color][color=000000]X [/color][color=007F00]'prints 0
[/color][color=000000]1220 SE[/color][color=8000FF]= [/color][color=000000]1[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]= [/color][color=000000]1[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE= 1:SN= 1: ATAN2 should be  45" [/color][color=000000]X [/color][color=007F00]'prints 45
[/color][color=000000]1230 SE[/color][color=8000FF]= [/color][color=000000]1[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]= [/color][color=000000]0[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE= 1:SN= 0: ATAN2 should be  90" [/color][color=000000]X [/color][color=007F00]'prints 90
[/color][color=000000]1240 SE[/color][color=8000FF]= [/color][color=000000]1[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]=-[/color][color=000000]1[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE= 1:SN=-1: ATAN2 should be 135" [/color][color=000000]X [/color][color=007F00]'prints 135
[/color][color=000000]1250 SE[/color][color=8000FF]= [/color][color=000000]0[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]=-[/color][color=000000]1[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE= 0:SN=-1: ATAN2 should be 180" [/color][color=000000]X [/color][color=007F00]'prints 180
[/color][color=000000]1260 SE[/color][color=8000FF]=-[/color][color=000000]1[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]=-[/color][color=000000]1[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE=-1:SN=-1: ATAN2 should be 225" [/color][color=000000]X [/color][color=007F00]'prints 225
[/color][color=000000]1270 SE[/color][color=8000FF]=-[/color][color=000000]1[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]= [/color][color=000000]0[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE=-1:SN= 0: ATAN2 should be 270" [/color][color=000000]X [/color][color=007F00]'prints 270
[/color][color=000000]1280 SE[/color][color=8000FF]=-[/color][color=000000]1[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]= [/color][color=000000]1[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE=-1:SN= 1: ATAN2 should be 315" [/color][color=000000]X [/color][color=007F00]'prints 315
[/color][color=000000]1290 SE[/color][color=8000FF]= [/color][color=000000]0[/color][color=8000FF]:[/color][color=000000]SN[/color][color=8000FF]= [/color][color=000000]1[/color][color=8000FF]:[/color][color=0000C0]GOSUB [/color][color=000000]1910[/color][color=8000FF]: [/color][color=0000C0]PRINT [/color][color=C020C0]"For SE= 0:SN= 1: ATAN2 should be   0" [/color][color=000000]X [/color][color=007F00]'prints 0
     [/color][color=0000C0]WAITKEY$
     EXIT FUNCTION
[/color][color=000000]1910 [/color][color=0000C0]IF [/color][color=000000]SN[/color][color=8000FF]=[/color][color=000000]0 [/color][color=0000C0]THEN [/color][color=000000]X[/color][color=8000FF]=-([/color][color=000000]SE[/color][color=8000FF]<>[/color][color=000000]0[/color][color=8000FF])*([/color][color=000000]90[/color][color=8000FF]-([/color][color=000000]SE[/color][color=8000FF]<[/color][color=000000]0[/color][color=8000FF])*[/color][color=000000]180[/color][color=8000FF]) [/color][color=0000C0]ELSE [/color][color=000000]X[/color][color=8000FF]=[/color][color=0000C0]ATN[/color][color=8000FF]([/color][color=000000]SE[/color][color=8000FF]/[/color][color=000000]SN[/color][color=8000FF])*[/color][color=000000]R1[/color][color=8000FF]-([/color][color=000000]SN[/color][color=8000FF]<[/color][color=000000]0[/color][color=8000FF])*[/color][color=000000]180[/color][color=8000FF]:[/color][color=0000C0]IF [/color][color=000000]X[/color][color=8000FF]<[/color][color=000000]0 [/color][color=0000C0]THEN [/color][color=000000]X[/color][color=8000FF]=[/color][color=000000]X[/color][color=8000FF]+[/color][color=000000]360
1920 [/color][color=0000C0]RETURN

END FUNCTION
[/color]

atan2 test.zip

[Dale Yarker]

Strickley in answer to question -

For extended-precision values, make the necessary changes.

change - LOCAL R1, SE, SN, X AS SINGLE
to - LOCAL R1, SE, SN, X AS EXTENDED
plus change degrees to radians

(no other checks made for run time errors or compile time errors)

((The ATN function in PB is natively extended.))

[Arthur Gomide]

Strickley in answer to question -

Hello Dale,
Now I'm confused ...I didn't do a question. I just put a code for calculating the ATAN2 function. The complete code is on line 1910. I also know that the PB ATN function returns its value in extended-precision and the ATAN2 function will use this precision only if it is in the interest of the programmer. Typically, implementations of the ATAN2 function takes some space, I'd say about 10 lines of code - This version fit in just one line! But yes, to run in extended precision are necessary the changes that you indicated.
Anyway my thanks!
Arthur.

    LOCAL R1, SE, SN, X AS EXT  'single

120 R1=5.72957795130823209e+01##    '57.29578!