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[Tutorials] Tutorial of how to plot residuals !

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Old   August 18, 2020, 23:38
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  #161
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Hi Peter,

Thanks a lot for the suggestion.


I changed the script as u said


My Script:
----------------------------------------------------------------------------------------------------------------------------
set xrange [1:*]
set logscale y
set title "Residuals"
set ylabel 'Residual'
set xlabel 'Iteration'
plot "< cat log | grep 'Solving for Ux' | cut -d' ' -f9 | tr -d ','" title 'Ux' with lines,\
"< cat log | grep 'Solving for Uy' | cut -d' ' -f9 | tr -d ','" title 'Uy' with lines,\
"< cat log | grep 'Solving for Uz' | cut -d' ' -f9 | tr -d ','" title 'Uz' with lines,\
"< cat log | grep 'Solving for omega' | cut -d' ' -f9 | tr -d ','" title 'omega' with lines,\
"< cat log | grep 'Solving for k' | cut -d' ' -f9 | tr -d ','" title 'k' with lines,\
"< cat log | grep 'Solving for p' | cut -d' ' -f9 | tr -d ','" title 'p' with lines
pause 1
reread
------------------------------------------------------------------------------------------------------------------------

But, still I am getting error message...

---------------------------------------------------------------------------------------------------------------------------------------------------------------
gnuplot> load "Residuals"
"Residuals" line 11: warning: Skipping data file with no valid points
"Residuals" line 11: warning: Skipping data file with no valid points
"Residuals" line 11: warning: Skipping data file with no valid points
"Residuals" line 11: warning: Skipping data file with no valid points
"Residuals" line 11: warning: Skipping data file with no valid points
"Residuals" line 11: warning: Skipping data file with no valid points

gnuplot> plot "< cat log | grep 'Solving for Ux' | cut -d' ' -f9 | tr -d ','" title 'Ux' with lines, "< cat log | grep 'Solving for Uy' |
cut -d' ' -f9 | tr -d ','" title 'Uy' with lines, "< cat log | grep 'Solving for Uz' | cut -d' ' -f9 | tr -d ','" title 'Uz' with lines,
"< cat log | grep 'Solving for omega' | cut -d' ' -f9 | tr -d ','" title 'omega' with lines, "< cat log | grep 'Solving for k' | cut
-d' ' -f9 | tr -d ','" title 'k' with lines, "< cat log | grep 'Solving for p' | cut -d' ' -f9 | tr -d ','" title 'p' with lines



^
"Residuals" line 11: x range is invalid
--------------------------------------------------------------------------------------------------------------------------------------------------------------


Plese help me out...
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Old   August 19, 2020, 21:59
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  #162
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I executed your skript on a case of mine.

It works actualy...

I dont see a problem with it.

Regards

Peter
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Last edited by peterhess; August 20, 2020 at 05:47.
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Old   December 2, 2020, 12:21
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For those of you who are stuck with plotting residuals from the Windows Subsystem for Linux (bash under windows), please see the following link for some possible solutions:


Plot the residuals using pyFoamPlotWatcher
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Old   January 21, 2021, 15:47
Default gnuplot not plotting residuals
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Hello,
I have followed your steps but I don't succeed to plot any residuals at all.
Here the error I get:

[
gnuplot> load 'residuals.gnu'
"residuals.gnu" line 10: warning: Skipping data file with no valid points
"residuals.gnu" line 10: warning: Skipping data file with no valid points
"residuals.gnu" line 10: warning: Skipping data file with no valid points
"residuals.gnu" line 10: warning: Skipping data file with no valid points
"residuals.gnu" line 10: warning: Skipping data file with no valid points
"residuals.gnu" line 10: warning: Skipping data file with no valid points

gnuplot> plot "< cat logS | grep 'Solving for Ux' | cut -d' ' -f4 | tr -d ','" title 'Ux' with lines,
"< cat logS | grep 'Solving for Uy' | cut -d' ' -f5 | tr -d ','" title 'Uy' with lines,
"< cat logS | grep 'Solving for Uz' | cut -d' ' -f9 | tr -d ','" title 'Uz' with lines,
"< cat logS | grep 'Solving for omega' | cut -d' ' -f9 | tr -d ','" title 'omega' with lines,
"< cat logS | grep 'Solving for k' | cut -d' ' -f9 | tr -d ','" title 'k' with lines,
"< cat logS | grep 'Solving for p' | cut -d' ' -f9 | tr -d ','" title 'p' with lines

^
"residuals.gnu" line 10: x range is invalid
]

Here is an extract of the 'logS' file:

[
Time = 601

smoothSolver: Solving for Ux, Initial residual = 0.00152791, Final residual = 1.34114e-06, No Iterations 10
smoothSolver: Solving for Uy, Initial residual = 0.00188445, Final residual = 1.40107e-06, No Iterations 11
smoothSolver: Solving for Uz, Initial residual = 0.000782393, Final residual = 6.19569e-07, No Iterations 10
GAMG: Solving for p, Initial residual = 0.0083305, Final residual = 3.68604e-05, No Iterations 4
GAMG: Solving for p, Initial residual = 0.000366117, Final residual = 2.0491e-06, No Iterations 4
time step continuity errors : sum local = 1.35357e-05, global = -1.07648e-06, cumulative = 1.73712
smoothSolver: Solving for omega, Initial residual = 2.75059e-06, Final residual = 7.9774e-09, No Iterations 9
smoothSolver: Solving for k, Initial residual = 0.00298973, Final residual = 2.85537e-06, No Iterations 11
ExecutionTime = 14.02 s ClockTime = 14 s
]


Is there anyone who can help me understanding this problem ?


Gnuplot is v5.4 installed on W10
OF is v2012 installed on Ubuntu 20.04 WSL2
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Old   July 22, 2022, 08:08
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how can i plot the value of max temperature in my domain?
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Old   September 29, 2022, 10:54
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Hi all
In my cases i have the following data

GMRES iteration:0 Residual: value 1 value 2 value 3
GMRES iteration:1 Residual: value 4 value 5 value 6

How can i select the value 2?

Regards
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Old   September 29, 2022, 12:02
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Flavio Galeazzo
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You can try this:

plot "< cat log | grep 'GMRES iteration:0' | cut -d' ' -f7 | tr -d ','" title 'Value 2' with lines
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Old   September 29, 2022, 12:26
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Quote:
Originally Posted by flavio_galeazzo View Post
You can try this:

plot "< cat log | grep 'GMRES iteration:0' | cut -d' ' -f7 | tr -d ','" title 'Value 2' with lines
Thank you very much

What if they are in the form of

GMRES iteration:0 Residual: (value 1 value 2 value 3)
GMRES iteration:1 Residual: (value 4 value 5 value 6)

and i want to pick up value 1, in that case -f6 or whatever -f number does not work because of the parenthesis i guess. I received "invalid x range" error.

What could be done for this case?
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Old   September 29, 2022, 12:36
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Ok, try this instead

plot "< cat log | grep 'GMRES iteration:0' | cut -d' ' -f4 | tr -d '('" title 'Value 1' with lines
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Old   October 5, 2022, 15:01
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Quote:
Originally Posted by bioexplore View Post
Hi, can this method applicable to parallel cases?
Yes, you can apply as long as you have merged solution log if I am not wrong.
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Old   January 14, 2024, 17:01
Post This thread is long, let's make it longer!
  #171
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Quote:
Originally Posted by wolle1982 View Post
Hi all,

since apearantly noone has an idea of how to plot the residuals of a calculation on-the-fly, I will give a small manual on that:

Tutorial on "How to plot the residuals (and forces) graphically on screen on-the-fly"

Step 1:
Start the calculation and make it write out a log-file. for example
turbFoam >log
"log" is the name of the log-file to be output. It is written into the main-case-folder.

Step 2:
If desired you can open a new console-window of the main-case-folder and follow the text-output by the command
tail -f log
"log" is the name of the log-file to be read in. To stop reading the file constantly just use Crtl+C

Step 3:
To plot the residuals graphically on the screen you can use gnuplot that is delivered with linux already.
Within the main-case-folder you have to put a text file with a name e.g. "Residuals"
(also see attachments).
The file should contain the following gnuplot properties:
set logscale y
set title "Residuals"
set ylabel 'Residual'
set xlabel 'Iteration'
plot "< cat log | grep 'Solving for Ux' | cut -d' ' -f9 | tr -d ','" title 'Ux' with lines,\
"< cat log | grep 'Solving for Uy' | cut -d' ' -f9 | tr -d ','" title 'Uy' with lines,\
"< cat log | grep 'Solving for Uz' | cut -d' ' -f9 | tr -d ','" title 'Uz' with lines,\
"< cat log | grep 'Solving for omega' | cut -d' ' -f9 | tr -d ','" title 'omega' with lines,\
"< cat log | grep 'Solving for k' | cut -d' ' -f9 | tr -d ','" title 'k' with lines,\
"< cat log | grep 'Solving for p' | cut -d' ' -f9 | tr -d ','" title 'p' with lines
pause 1
reread
The pause-command sets the seconds till reload. Deletion makes it faster in some cases.

Execute the command
gnuplot Residuals -
in the main-case-folder.

Step 4:
Another good indicator for the calculations convergence is the forces-plot. Therefore you have to set the function in the controlDict that calculates the forces and forceCoeffs. See thread http://www.cfd-online.com/Forums/ope...es-of15-3.html or attachments.

Be sure to have the properties for gnuplot in the main-case-folder (see attachments).

You have the adapt the folder-name where the forceCoeffs.dat is inside before.

While the calculation runs you also can use the gnuplot command
gnuplot forceCoeffs -
in the main-case-folder. When the forces seem to not change any more, the pressure allocation must be constantly what makes the convergent case proofed.

Step5:
Plotting the real forces is also easy. Proceed identically like in "Step 4" but be sure to set
magUInf 1.0; //free stream velocity magnitude
lRef 1.0; //reference length
Aref 1.632653; //reference area
in the controlDict.

Using the attached text-files, remove the ".txt" first.

Hope that helps somebody.

Greetings,
Wolfgang
Thank you Wolfgang for this great post. I also made some edits specific to my use case which I thought I'd share in case it helps someone. In particular:
  • Ascii display for remote viewing. Running the command once will plot the residuals once. If you wish to continuously update the plot; I use:
    Code:
    watch -n2 gnuplot residuals.gp
    This allows me to watch residuals in real time remotely, as I often don't have graphical capabilities. I currently have it set quite large ('set term dumb 100 40' -> 100 x 40) but you could easily change this.
  • Supports a single command line log file argument:
    Code:
    gnuplot -e "filename='log.buoyantSimpleFoam'" residuals.gp

An example of the script running:

Code:
loading log.buoyantSimpleFoam...

                                                                                                    
                                                                                                    
                                                Residuals                                           
     1e0 +--------------------------------------------------------------------------------------+   
         |+             +             +              +             +              +            +|   
         |+                                                                           k *******+|   
         |####                                                                        p #######+|   
         |   ##       ###                                                           eps $$$$$$$ |   
    1e-1 |-+  ##     ######  ####                                                             +-|   
         |+    ##   ##    ####  ##     #####                                                   +|   
         |+     ## ##      ##    ###  ##   ##  #####      ###                                  +|   
         |+      ###       ##      ####     ####   ##   ### ##   #####                         +|   
    1e-2 |-+      #        ##       ##        #     #####    #####   ##   ######              +-|   
         |+       #        #        ##                ##      ##      ## ##    #  ##           +|   
         |+                                                            ###     ####            +|   
         |+                                                                     ##             +|   
         |+                                                                                    +|   
    1e-3 |*+                                                                                  +-|   
         |*                                                                                    +|   
         |$**                                                                                  +|   
         |$ **                                                                                 +|   
         |$  **                                                                                 |   
    1e-4 |$$  ****        ******                                                              +-|   
         |+$$    *****  ***    **    ***                                                       +|   
         |+ $        ****       ** *** ***   *****                                             +|   
         |+ $$             $$$   ***     *****   **  ******     ***                            +|   
         |   $$$$$$$    $$$$ $$           **      ****    ** **** ***   *****                   |   
    1e-5 |-+     $$$$$$$$     $$   $$$$$     $$$           ***      *****   **  ****          +-|   
         |+                    $$ $$   $$  $$$ $$     $$$            *       ****              +|   
         |+                     $$$     $$$$    $$ $$$$ $$    $$$$$                            +|   
         |+                      $       $$      $$$     $$ $$$   $$ $$$$$$$                   +|   
    1e-6 |-+                                              $$$      $$$     $$ $$$$$$          +-|   
         |+                                                                 $$$                +|   
         |+                                                                                    +|   
         |+                                                                                    +|   
         |+             +             +              +             +              +            +|   
    1e-7 +--------------------------------------------------------------------------------------+   
         0             5000         10000          15000         20000          25000         30000 
                                                Iteration
I have the residuals.gp file hidden in my home directoy and linked to an alias in my .bashrc, so I can quickly run it and check wherever I may be:

Code:
# run this with the name of the log file, i.e.
#    - ofresiduals log
ofresiduals() {
    gnuplot -e "filename='$1'" ~/.of.residuals.gp
}
Thanks again for this fantastic thread!

Diego
Attached Files
File Type: txt residuals.txt (993 Bytes, 5 views)

Last edited by Hip2BL7; January 14, 2024 at 17:31. Reason: doesn't work with watch! will have to edit...
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Old   February 20, 2024, 02:55
Lightbulb How to plot residuals in OpenFOAM-v2312 ?
  #172
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To visualize residuals on a logarithmic scale in OpenFOAM version 2312 (OF-v2312), it is necessary to have a solverInfo file defined in the system.

You can refer to example files located at 'etc/caseDicts/postProcessing/numerical' for guidance on setting up the solverInfo file. This file plays a crucial role in enabling the plotting of residuals with logarithmic scaling for a more insightful analysis.

The following bash script can be used to plot the residuals:
Code:
#!/bin/bash

# path
path="postProcessing/solverInfo/0/solverInfo.dat"
result="Residuals.png"

# Extract the data in the relevant columns
awk '{print $1, $4, $9, $14, $19}' $path > extracted_data.txt

# Log Scale Plot
gnuplot <<- GNU
set terminal png size 1200,600 font "Times New Roman, 16"
set output "$result"
set xlabel "Time"
set ylabel "Residual"
set logscale y
set format y "10^{%T}"
set key font "Times New Roman, 16"
set label font "Times New Roman, 16"
set xlabel font "Times New Roman, 16"
set ylabel font "Times New Roman, 16"
set xtics font "Times New Roman, 16"
set ytics font "Times New Roman, 16"

plot "extracted_data.txt" using 1:2 with lines lw 1 title "alpha.water", \
     "extracted_data.txt" using 1:3 with lines lw 1 title "epsilon", \
     "extracted_data.txt" using 1:4 with lines lw 1 title "k", \
     "extracted_data.txt" using 1:5 with lines lw 1 title "p_{rgh}"

GNU
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