The code below is supposed to output

A = 0.00000000000000000000
B = 0.00000000000000000000
C = 0.00000000000000000000
D = 0.00000000000000000000

*every* time it is run.
But sometimes the numbers change to random numbers.

It doesn't happen every time, but if the code is run - say 20 times - the
probability is high. Try to render it as an animation, and watch the
numbers.

I use Windows 95, MegaPOV 0.6A.
Can anyone confirm it?

#version unofficial MegaPOV 0.6;
camera {
   location 6*x
   look_at 0
   translate 2*y
}
light_source {<1,2,3>, color 1}
#declare Q = array[4][4] {
   {<1.6,2.5,6.1>, <2.4,0.0,0.0>, <0.2,4.7,6.3>, <2.4,2.5,5.5>,},
   {<4.3,8.0,5.0>, 0,             0,             <8.5,0.0,1.3>,},
   {<1.5,4.3,2.0>, 0,             0,             <1.4,0.3,7.1>,},
   {<2.6,2.2,1.1>, <5.4,0.0,0.0>, <3.2,2.6,3.6>, <2.3,2.2,1.4>,},
}
#declare P = Q
#debug "\nA = " #debug str(vlength(P[1][1]),0,20)
#debug "\nB = " #debug str(vlength(P[1][2]),0,20)
#debug "\nC = " #debug str(vlength(P[2][2]),0,20)
#debug "\nD = " #debug str(vlength(P[2][1]),0,20)
box{1,1 pigment {color 0}}

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Rune wrote:

> Can anyone confirm it?

Yep - I got B = -1.#QNAN00000000000 at one point
C = 0.89999961853027344000 at another point
D = 0.00781250000000000000 at another point
B = 1.00000000000000000000 at another point
and then MP crashed?
WMP 0.6a on WinNT
--
Bye
Pabs

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"Rune" <run### [at] inamecom> wrote in message
news:3a17fa50@news.povray.org...

also confirmed mp6.0a on win2000 - weird bug.

BTW removing the final comma at the end of the array makes no difference to
the bug.

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Using MegaPov 0.4, 0.6a or Pov3.1g, all DOS versions, and Win98SE I
get a scrolling screenfull of this stuff:

>Page fault at eip=0010ecd1, error=0004
>eax=00012ee4 ebx=00000000 ecx=00000000 edx=001bd11c esi=00000000
edi=0000000e
>ebp=0013d9e4 esp=0013d9d0 program=Exiting due to signal SIGSEGV
>Page fault at eip=0010ecd1, error=0004
>eax=00012ee4 ebx=00000000 ecx=00000000 edx=001bd11c esi=00000000
edi=0000000e
>ebp=0013d89c esp=0013d888 program=Exiting due to signal SIGSEGV

However, it seems dependant on how you invoke pov, (bat file or cmd
line for example) and what you've done previously. Consecutive runs
give identical results. Other runs, using +GA, gave consecutive:

>ANaN
>B = 0.00000000000000000000
>C = 0.00000000000000000000
>D = 0.00000000000000000000

or

>light_source {<1,2,3>, color 1}
>#declare Q = array[4][4] {
>   {<1.6,2.5,6.1>, <2.4,0.0,0.0>, <0.2,4.7,6.3>, <2.4,2.5,5.5>,},
>   {<4.3,8.0,5.0>, 0, <----ERROR
>
>tmpm.pov:33: error: Attempted to redefine vector identifier as float
identifier.
(tmpm.pov was your post with non-pov stuff commented out.)

It will also give correct results in a run.

Alf

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It doesn't seem to matter if you have the

 #declare P = Q

in the code either, I tried replacing P for Q in
the array declaration, commented out the P=Q
assignment, and the bug persisted. However,
after I formally entered the vectors <0,0,0> in
the array, the bug disappeared.

Win NT 4.0, Sp6, 128Mb ram, PII 400.
=Bob=


"Rune" <run### [at] inamecom> wrote in message
news:3a17fa50@news.povray.org...
: The code below is supposed to output
:
: [code example deleted]

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"=Bob=" wrote:
> It doesn't seem to matter if you have the
>
>  #declare P = Q
>
> in the code either

When I was hunting down the source of the bug, it seemed like it happened
less often the more I simplified the scene. So I kept some elements in
there.

> after I formally entered the vectors <0,0,0> in
> the array, the bug disappeared.

I know, it seems like it has something to do with floats vs. vectors.

Rune
--
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\ all be found at http://rsj.mobilixnet.dk (updated October 9)
/ Also visit http://www.povrayusers.org

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I'd guess that it was a parsing error, at least
that's where I'd start looking.
=Bob=

"Rune" <run### [at] inamecom> wrote in message
news:3a2a7177@news.povray.org...

I said:
: > after I formally entered the vectors <0,0,0> in
: > the array, the bug disappeared.
:
: I know, it seems like it has something to do with floats vs. vectors.
:
: Rune
: --
: \ Include files, tutorials, 3D images, raytracing jokes,
: / The POV Desktop Theme, and The POV-Ray Logo Contest can
: \ all be found at http://rsj.mobilixnet.dk (updated October 9)
: / Also visit http://www.povrayusers.org

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