asterisk users - Oct 2016 - Problem with REMAINDER? 957%60 be 15 remainder 57 not 15 remainder -3 ?

I'm not mathematically gifted, but shouldn't 957%60 be 15 remainder 57?

Google and my desktop calculator certainly think so.

So where am I going wrong here? The following code

 exten => 7,1,Verbose(Context: ${CONTEXT} Exten:${EXTEN})
    same => n,Set(myNum=957)
    same => n,Set(sec=$[REMAINDER(${myNum},60)])
    same => n,Set(sec=$[ABS(${sec})])
    same => n,Set(sec=$[${MATH(${sec}+0,i)}])
    same => n,Verbose(1,${myNum},${sec})
gives me

    -- Executing [7 at fromvoipfone201:1]
Verbose("PJSIP/6001-00000007",
"Context: fromvoipfone201 Exten:7") in new stack
Context: fromvoipfone201 Exten:7
    -- Executing [7 at fromvoipfone201:2] Set("PJSIP/6001-00000007",
"myNum=957") in new stack
    -- Executing [7 at fromvoipfone201:3] Set("PJSIP/6001-00000007",
"sec=-3") in new stack
    -- Executing [7 at fromvoipfone201:4] Set("PJSIP/6001-00000007",
"sec=3") in new stack
    -- Executing [7 at fromvoipfone201:5] Set("PJSIP/6001-00000007",
"sec=3") in new stack
    -- Executing [7 at fromvoipfone201:6]
Verbose("PJSIP/6001-00000007",
"1,957,3") in new stack

Where is -3 coming from?!?

I can flip it around by using ABS to stop people freaking out when
they hear a track is "15 minutes minus 3 seconds long", but it's
still
incorrect, isn't it?

(I add the second MATH function to everything I do now to make it an
integer as it seems you never can tell with Asterisk, just ignore it!)

Any ideas? Thanks.

All I can tell you is where -3 comes from.
>From http://www.voip-info.org/wiki/view/Asterisk+Expressions :
REMAINDER(x,y) computes the remainder of dividing x by y. The return value
is x - n*y, where n is the value x/y, rounded to the nearest integer. If
this quotient is 1/2, it is rounded to the nearest even number.

-3 comes from:
n = x/y = 957/60 = 15.95 which rounds to 16
n*y = 16*60 = 960
x - 960 = 957-960 = -3

I'm not mathematically gifted either but I think the n is the problem. it
shouldn't be the rounded result it should be the integer part of x/y (n=15)

Can you just use modulo instead: ${MATH(${myNum}%60,int)}
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Yes! That's the one. Thank you. That's a good workaround.

The following test dialplan shows the bug (feature?)

 exten => 7,1,Verbose(Context: ${CONTEXT} Exten:${EXTEN})
    same => n,Set(seconds=57)
    same => n,While($[${seconds} <= 400]);
    same => n,Set(minutes=$[FLOOR(${seconds} / 60)])
    same => n,Set(myRemainderSec=$[REMAINDER(${seconds},60)])
    same => n,SET(myModSec=${MATH(${seconds}%60,int)})
    same => n,Verbose(1,Seconds:${seconds} = Minutes:${minutes}
Remainder Seconds:${myRemainderSec} modulo seconds:${myModSec})
    same => n,Set(seconds=$[${seconds}+3])
    same => n,EndWhile()

This is the output:

 Seconds:57 = Minutes:0 Remainder Seconds:-3 modulo seconds:57
 Seconds:60 = Minutes:1 Remainder Seconds:0 modulo seconds:0
 Seconds:63 = Minutes:1 Remainder Seconds:3 modulo seconds:3
 Seconds:66 = Minutes:1 Remainder Seconds:6 modulo seconds:6
 Seconds:69 = Minutes:1 Remainder Seconds:9 modulo seconds:9
 Seconds:72 = Minutes:1 Remainder Seconds:12 modulo seconds:12
 Seconds:75 = Minutes:1 Remainder Seconds:15 modulo seconds:15
 Seconds:78 = Minutes:1 Remainder Seconds:18 modulo seconds:18
 Seconds:81 = Minutes:1 Remainder Seconds:21 modulo seconds:21
 Seconds:84 = Minutes:1 Remainder Seconds:24 modulo seconds:24
 Seconds:87 = Minutes:1 Remainder Seconds:27 modulo seconds:27
 Seconds:90 = Minutes:1 Remainder Seconds:-30 modulo seconds:30
 Seconds:93 = Minutes:1 Remainder Seconds:-27 modulo seconds:33
 Seconds:96 = Minutes:1 Remainder Seconds:-24 modulo seconds:36
 Seconds:99 = Minutes:1 Remainder Seconds:-21 modulo seconds:39
 Seconds:102 = Minutes:1 Remainder Seconds:-18 modulo seconds:42
 Seconds:105 = Minutes:1 Remainder Seconds:-15 modulo seconds:45
 Seconds:108 = Minutes:1 Remainder Seconds:-12 modulo seconds:48
 Seconds:111 = Minutes:1 Remainder Seconds:-9 modulo seconds:51
 Seconds:114 = Minutes:1 Remainder Seconds:-6 modulo seconds:54
 Seconds:117 = Minutes:1 Remainder Seconds:-3 modulo seconds:57
 Seconds:120 = Minutes:2 Remainder Seconds:0 modulo seconds:0

Issue filed at https://issues.asterisk.org/jira/browse/ASTERISK-26493

On 21 October 2016 at 16:27, James Thomas <jthomasdpu at gmail.com>
wrote:
> All I can tell you is where -3 comes from.
> From http://www.voip-info.org/wiki/view/Asterisk+Expressions :
> REMAINDER(x,y) computes the remainder of dividing x by y. The return value
> is x - n*y, where n is the value x/y, rounded to the nearest integer. If
> this quotient is 1/2, it is rounded to the nearest even number.
>
> -3 comes from:
> n = x/y = 957/60 = 15.95 which rounds to 16
> n*y = 16*60 = 960
> x - 960 = 957-960 = -3
>
> I'm not mathematically gifted either but I think the n is the problem.
it
> shouldn't be the rounded result it should be the integer part of x/y
(n=15)
>
> Can you just use modulo instead: ${MATH(${myNum}%60,int)}
>
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