Bug with ACos and ASin

[oldbrother]

Please see the test code below.

C := A-B = 0.24

if C is calculated, both ACos and ASin are not working properly.

If C is given 0.24, the results are ok.

It looks like a serious bug for math functions. AHK.L 1.1.26.00

Code: Select all

A:=8.5
B:=8.26
C:= A-B
Ang1 :=ACos(C/0.240)
Ang2 :=ASin(C/0.240)
	      	
Msgbox % "c: " C "  Ang1:   " Ang1 "  Ang2:   " Ang2 


C:= 0.24
Ang1 :=ACos(C/0.240)
Ang2 :=ASin(C/0.240)
	      	
Msgbox % "c: " C "  Ang1:   " Ang1 "  Ang2:   " Ang2 

[jeeswg]

I get blanks for the first MsgBox and correct answers for the second MsgBox.

If I add SetFormat, Float, 0.6, then I get the same answers for both.

So it might be related to this:
(var1 = var2) inconsistent on different scripts - AutoHotkey Community
https://autohotkey.com/boards/viewtopic.php?f=5&t=34103

[Helgef]

Arcsin and arccos are only defined in the range [-1,1]. The float failing is probably 1.00...00x, x>0, due to float inaccuracy.

[oldbrother]

l know the reason, and I know the ways walking round, but I just think these kinds of bugs are better be fixed at the bases.

[Helgef]

Oldbrother, the bug is in your code, you are calling the function with invalid parameters.

Cheers.

Personally, I think invalid paramters should throw an exception, it is much better to get notified directly when one has made a mistake, rather than getting blanks from unknown origin.

[nnnik]

The base that causes the problem is binary logic. Have fun fixing that.

Code: Select all

SetFormat, FloatFast, 15.30
A:=8.5
B:=8.26
C:= A-B
Ang1 :=ACos(C/0.24)
Ang2 :=ASin(C/0.240)

Msgbox % "c: " C "  Ang1:   " Ang1 "  Ang2:   " Ang2 


C:= 0.24 + 0.0
Ang1 :=ACos(C/0.240)
Ang2 :=ASin(C/0.240)

Msgbox % "c: " C "  Ang1:   " Ang1 "  Ang2:   " Ang2

[oldbrother]

SetFormat seems cannot solve the problem.

nnnik, with your modified code, the first msgbox still gets blank Ang1 and Ang2.

My working around is C:= Round(C,10)

The real reason is A-B = 8.5-8.26 = 0.2400000000000002100000

Oldbrother, the bug is in your code, you are calling the function with invalid parameters.

[just me]

If Number is less than -1 or greater than 1, the function yields a blank result (empty string).

Code: Select all

A := 8.5
B := 8.26
C := A - B
N := C / 0.240
MsgBox, % "N > 1.0 = " . (N > 1.0 ? "True" : "False")

[nnnik]

@oldbrother I merely wanted to show the Problem not fix it.