# How to write output data for a specific cell (ExtractSelection)

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 November 8, 2023, 23:17 How to write output data for a specific cell (ExtractSelection) #1 New Member   Vivek kumar Join Date: Mar 2021 Location: India Posts: 8 Rep Power: 5 Dear All, As I am interested to write a particular cell data from the whole domain in SU2 code, because When I am writing the data for a full domain it is taking too much time and memory. Can anyone please help me to do this ? Thanks in advance regards Vivek Kumar, India Last edited by vivekdixit194; November 9, 2023 at 07:40.

 November 9, 2023, 16:00 #2 Senior Member   bigfoot Join Date: Dec 2011 Location: Netherlands Posts: 529 Rep Power: 17 You can add monitoring points, which are called probes in SU2. The documentation is here: https://su2code.github.io/docs_v7/Custom-Output/ You could do this to output the velocity in a point P(0.1, 0.2, 0.3): Code: ```CUSTOM_OUTPUTS='velocity : Macro{sqrt(pow(VELOCITY_X, 2) + pow(VELOCITY_Y, 2) + pow(VELOCITY_Z, 2))};\ point1 : Probe{\$velocity}[0.1, 0.2, 0.3]'```

 November 21, 2023, 02:39 Error in writing the Tempertaure for a specific cell (Not for all the cells ) #3 New Member   Vivek kumar Join Date: Mar 2021 Location: India Posts: 8 Rep Power: 5 Dear, Thanks a lot for your response. I was using the same documents given in the SU2 webpage but It is giving error. I have used CUSTOM_OUTPUTS= 'velocity : Macro{sqrt(pow(VELOCITY_X, 2) + pow(VELOCITY_Y, 2) + pow(VELOCITY_Z, 2))};\ avg_vel : AreaAvg{\$velocity}[z_minus, z_plus];\ var_vel : AreaAvg{pow(\$velocity - avg_vel, 2)}[z_minus, z_plus];\ dev_vel : Function{sqrt(var_vel) / avg_vel};\ probe1 : Probe{\$velocity}[0.005, 0.005, 0.05]' But the error in the terminal is shown as Error in "void CFlowOutput::ConvertVariableSymbolsToIndices(const CPrimitiveIndices&, bool, COutput::CustomOutput&) const": ------------------------------------------------------------------------- Invalid history output or solver variable (VELOCITY_Z) used in function avg_vel Valid solvers variables: CP_TOTAL DENSITY EDDY_VISCOSITY LAMINAR_VISCOSITY PRESSURE SOUND_SPEED TEMPERATURE THERMAL_CONDUCTIVITY VELOCITY_X VELOCITY_Y TURB[0,1,...] RAD[0,1,...] SPECIES[0,1,...] SCALAR[0,1,...] ------------------------------ Error Exit ------------------------------- I would like to tell you that I am interested in finding out the temperature for a specific point and dont want to write the temperature for all the domain. Thanks in advance

 November 21, 2023, 03:08 Not writing the specific cell data #4 New Member   Vivek kumar Join Date: Mar 2021 Location: India Posts: 8 Rep Power: 5 If I am removing the Z points from the probe, still not writing the specific cell data. Still writing the whole domain data without any error.

 November 21, 2023, 07:37 #5 Senior Member   bigfoot Join Date: Dec 2011 Location: Netherlands Posts: 529 Rep Power: 17 Where are you looking?

 November 22, 2023, 01:06 Not writing the specific cell data #6 New Member   Vivek kumar Join Date: Mar 2021 Location: India Posts: 8 Rep Power: 5 Dear, I am adding few lines as suggested by you in my config file, CUSTOM_OUTPUTS= 'velocity : Macro{sqrt(pow(VELOCITY_X, 2) + pow(VELOCITY_Y, 2))};\ avg_vel : AreaAvg{\$velocity}[z_minus, z_plus];\ var_vel : AreaAvg{pow(\$velocity - avg_vel, 2)}[z_minus, z_plus];\ dev_vel : Function{sqrt(var_vel) / avg_vel};\ probe1 : Probe{\$velocity}[0.1032, 0.8036]' SCREEN_OUTPUT= INNER_ITER, RMS_DENSITY, RMS_ENERGY, LINSOL_RESIDUAL, FORCE_Z,\ SURFACE_MASSFLOW, SURFACE_TOTAL_TEMPERATURE, avg_vel, dev_vel, probe1, COMBO HISTORY_OUTPUT = ITER, AERO_COEFF, FLOW_COEFF, FLOW_COEFF_SURF, CUSTOM, COMBO OBJECTIVE_FUNCTION= CUSTOM_OBJFUNC CUSTOM_OBJFUNC= 'SURFACE_TOTAL_TEMPERATURE' But After running my code, Still It is writing Whole volume file as I am not interested in writing the values for all the domain. Please help me to write only cell data because it is taking 4MB file for a single iteration.

 November 22, 2023, 01:46 How to write only probe data #7 New Member   Vivek kumar Join Date: Mar 2021 Location: India Posts: 8 Rep Power: 5 Dear, Can you please help me to write only probe data ? CUSTOM_OUTPUTS='temperature : Macro{TEMPERATURE};\ probe1 : Probe{\$temperature}[0.1032, 0.8036]'

 November 22, 2023, 02:25 #8 Senior Member   bigfoot Join Date: Dec 2011 Location: Netherlands Posts: 529 Rep Power: 17 I meant in which output file are you looking, it seems that you are looking in the volume output file, but the custom output is written to the history file.

 November 22, 2023, 06:39 Custom output is written in history file not in Volume file. #9 New Member   Bihar Join Date: May 2023 Posts: 3 Rep Power: 2 Dear, Got it. Thank you so much for your help.

 November 25, 2023, 06:04 Error: The current solver can only use 'Function' custom outputs. #10 New Member   Vivek kumar Join Date: Mar 2021 Location: India Posts: 8 Rep Power: 5 Dear, I am getting Error. Error in "void COutput::ComputeSimpleCustomOutputs(const CConfig*)": ------------------------------------------------------------------------- The current solver can only use 'Function' custom outputs. ------------------------------ Error Exit ------------------------------- I am using MULTIPHYSICS solver and trying to write the files in ELASTICITY Solver. Why i am getting this error ?. Please help me to fix this. thanks in advance

 Tags su2 7.2.0