# Difference between 2 Datasets
**URL:** https://discourse.paraview.org/t/difference-between-2-datasets/7337
**Category:** ParaView Support
**Created:** [June 1, 2021, 1:43pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337 "2021-06-01T13:43:04Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@frank\_forster](https://discourse.paraview.org/u/frank_forster)
#### Post date: [June 1, 2021, 1:43pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/1 "2021-06-01T13:43:04Z")
Hello,
How can I get the difference about one component between two datasets ?
Let’s say one layer is 15°C and the other 10°C, I’d like to have a new layer with a field filled with -5°C.
Thanks, Frank
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 1, 2021, 1:45pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/2 "2021-06-01T13:45:02Z")
AppendAttributes + Calculator
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### Author:  [@Kenneth\_Moreland](https://discourse.paraview.org/u/Kenneth_Moreland)
#### Post date: [June 1, 2021, 1:48pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/3 "2021-06-01T13:48:02Z")
You might need either `Append Attributes` or `Resample with Dataset` depending on the structure of your data. See, for example: [Visualization of data using Paraview - #7 by Kenneth\_Moreland](https://discourse.paraview.org/t/visualization-of-data-using-paraview/4703/7)
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### Author:  [@frank\_forster](https://discourse.paraview.org/u/frank_forster)
#### Post date: [June 1, 2021, 2:08pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/4 "2021-06-01T14:08:39Z")
Hello and thanks for your answer,
I still have the same value on the “calculator”. Do I have a formula to write ?
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [June 1, 2021, 2:18pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/5 "2021-06-01T14:18:14Z")
Yes, write something like:
`Temp0 - Temp1`
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### Author:  [@frank\_forster](https://discourse.paraview.org/u/frank_forster)
#### Post date: [June 2, 2021, 10:23am UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/6 "2021-06-02T10:23:35Z")
Hello,
After some research, I’ve done it using a ProgrammableFilter with the following :
Thanks @mwestphal and @Kenneth_Moreland, Frank.
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### Author:  [@nicolas.vuaille](https://discourse.paraview.org/u/nicolas.vuaille)
#### Post date: [June 3, 2021, 3:43pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/7 "2021-06-03T15:43:27Z")
To do it in python you can also use the python calculator, with the one-liner
`inputs[1].PointData["TMRT"] - inputs[0].PoindData["TMRT"]`
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### Author:  [@frank\_forster](https://discourse.paraview.org/u/frank_forster)
#### Post date: [June 3, 2021, 7:08pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/8 "2021-06-03T19:08:49Z")
Way more convenient, thank you @nicolas.vuaille !
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### Author:  [@zj519](https://discourse.paraview.org/u/zj519)
#### Post date: [January 22, 2024, 4:22pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/9 "2024-01-22T16:22:28Z")
Hi Nicolas,
I’m trying to calculate mean sqaured error (MSE) between two datasets. I have used resample with dataset to make the two vtu fils have same number of cells and same number of points.
Now, i use the python calculator, but get an error as shown on the screenshot
May I kindly ask how this should be resolved please?
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### Author:  [@nicolas.vuaille](https://discourse.paraview.org/u/nicolas.vuaille)
#### Post date: [January 22, 2024, 4:59pm UTC](https://discourse.paraview.org/t/difference-between-2-datasets/7337/10 "2024-01-22T16:59:58Z")
Hi @zj519 ,
You have selected only one source in the pipeline for the `Python Calculator` input, so `inputs[1]` does not exist.