Round variable to nth digit

[nikscha]

Hi all,
when adding two floating point numbers in RRF, the result is sometimes not "right":

I'm aware that this is due to floats being of limited size, and it's usually not a problem.
But at the moment I need to look at a lot of them and it's just anoying/difficult to read.
I haven't found a round() function, and echo doesn't allow formatting either.
Any ideas how I can make it more readable?

[nikscha]

@nikscha
Found a solution: (but it's a bit tedious)

var x = global.variable_to_report
set var.x = var.x *10000
set var.x = floor(var.x)
set var.x = var.x/10000
echo "global.variable_to_report: ", var.x                  

Adjust the "10,000" to change the number of digits to be displayed.
Obviously this can be done in a single line too:

set var.x = floor(var.x *10000)/10000

Still not perfect as it doesn't do any rounding, but easier to read:

[dc42]

@nikscha it works for me:

This is with a build a little later than 3.5.0-rc.1. Which firmware version are you using?

[nikscha]

@dc42

Duet 6HC + SBC

edit:
M122:

=== Diagnostics ===
RepRapFirmware for Duet 3 MB6HC version 3.5.0-rc.1 (2023-08-31 16:19:24) running on Duet 3 MB6HC v1.01 (SBC mode)
Board ID: 08DJM-9P63L-DJ3S0-7J1F8-3S86T-TBJZ8
Used output buffers: 1 of 40 (25 max)
=== RTOS ===
Static ram: 154852
Dynamic ram: 90580 of which 1388 recycled
Never used RAM 96316, free system stack 194 words
Tasks: SBC(2,rWait:,3.2%,390) HEAT(3,nWait,0.1%,323) Move(4,nWait,0.0%,216) CanReceiv(6,nWait,0.3%,769) CanSender(5,nWait,0.0%,335) CanClock(7,delaying,0.0%,349) TMC(4,nWait,29.0%,59) MAIN(2,running,66.9%,137) IDLE(0,ready,0.5%,30), total 100.0%
Owned mutexes: HTTP(MAIN)
=== Platform ===
Last reset 04:25:03 ago, cause: software
Last software reset at 2023-09-25 12:01, reason: User, Gcodes spinning, available RAM 96316, slot 2
Software reset code 0x6003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0044a000 BFAR 0x00000000 SP 0x00000000 Task SBC Freestk 0 n/a
Error status: 0x00
Aux0 errors 0,0,0
MCU temperature: min 36.8, current 38.5, max 38.7
Supply voltage: min 24.1, current 24.1, max 24.2, under voltage events: 0, over voltage events: 0, power good: yes
12V rail voltage: min 12.0, current 12.1, max 12.1, under voltage events: 0
Heap OK, handles allocated/used 99/10, heap memory allocated/used/recyclable 2048/1228/992, gc cycles 14
Events: 0 queued, 0 completed
Driver 0: standstill, SG min n/a, mspos 8, reads 373, writes 20 timeouts 0
Driver 1: standstill, SG min n/a, mspos 8, reads 373, writes 20 timeouts 0
Driver 2: standstill, SG min n/a, mspos 8, reads 310, writes 84 timeouts 0
Driver 3: standstill, SG min n/a, mspos 8, reads 368, writes 26 timeouts 0
Driver 4: standstill, SG min n/a, mspos 8, reads 383, writes 11 timeouts 0
Driver 5: standstill, SG min n/a, mspos 8, reads 374, writes 20 timeouts 0
Date/time: 2023-09-25 16:26:27
Slowest loop: 60.73ms; fastest: 0.05ms
=== Storage ===
Free file entries: 20
SD card 0 not detected, interface speed: 37.5MBytes/sec
SD card longest read time 0.0ms, write time 0.0ms, max retries 0
=== Move ===
DMs created 125, segments created 0, maxWait 4088669ms, bed compensation in use: none, height map offset 0.000, ebfmin 0.00, ebfmax 0.00
no step interrupt scheduled
Moves shaped first try 0, on retry 0, too short 0, wrong shape 0, maybepossible 0
=== DDARing 0 ===
Scheduled moves 51, completed 51, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== DDARing 1 ===
Scheduled moves 0, completed 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== Heat ===
Bed heaters 0 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamber heaters -1 -1 -1 -1, ordering errs 0
Heater 4 is on, I-accum = 0.0
=== GCodes ===
Movement locks held by null, null
HTTP* is doing "M122" in state(s) 0
Telnet is idle in state(s) 0
File is idle in state(s) 0
USB is idle in state(s) 0
Aux is idle in state(s) 0
Trigger* is idle in state(s) 0
Queue is idle in state(s) 0
LCD is idle in state(s) 0
SBC is idle in state(s) 0
Daemon* is idle in state(s) 0 0, running macro
Aux2 is idle in state(s) 0
Autopause is idle in state(s) 0
File2 is idle in state(s) 0
Queue2 is idle in state(s) 0
Q0 segments left 0, axes/extruders owned 0x10000003
Code queue 0 is empty
Q1 segments left 0, axes/extruders owned 0x0000000
Code queue 1 is empty
=== CAN ===
Messages queued 144316, received 891581, lost 0, boc 0
Longest wait 56ms for reply type 6041, peak Tx sync delay 39028, free buffers 50 (min 49), ts 79516/79515/0
Tx timeouts 0,0,0,0,0,0
=== SBC interface ===
Transfer state: 5, failed transfers: 0, checksum errors: 0
RX/TX seq numbers: 24953/24953
SPI underruns 0, overruns 0
State: 5, disconnects: 0, timeouts: 0 total, 0 by SBC, IAP RAM available 0x25a98
Buffer RX/TX: 0/0-0, open files: 0
=== Duet Control Server ===
Duet Control Server version 3.5.0-rc.1 (2023-09-01 07:16:31)
Failed to deserialize the following properties:
- MoveSegmentation -> Int32 from 1.0
Daemon:
Buffered code: G4 P100
Buffered codes: 32 bytes total
>> Doing macro daemon.g, started by system
>> Number of flush requests: 1
Code buffer space: 4040
Configured SPI speed: 8000000Hz, TfrRdy pin glitches: 4
Full transfers per second: 38.66, max time between full transfers: 450.0ms, max pin wait times: 70.9ms/12.7ms
Codes per second: 6.72
Maximum length of RX/TX data transfers: 7884/1224

Edit2:
SBC is a Raspberry Pi 4

[dc42]

@nikscha I'll ask @chrishamm to take a look because I think this may be a difference between SBC and standalone modes.

PS - meanwhile, have you tried using floor(var.x+0.5) instead of floor(var.x) ?

[nikscha]

@dc42 Thanks, I'll give that a try!