# Using vtkArrayCalculator to multiply a vector array by a single scalar value

**URL:** https://discourse.vtk.org/t/using-vtkarraycalculator-to-multiply-a-vector-array-by-a-single-scalar-value/12594
**Category:** Support
**Created:** [October 31, 2023, 8:28pm UTC](https://discourse.vtk.org/t/using-vtkarraycalculator-to-multiply-a-vector-array-by-a-single-scalar-value/12594 "2023-10-31T20:28:09Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![bheld](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/8491ac/32.png) [@bheld](https://discourse.vtk.org/u/bheld)
#### Post date: [October 31, 2023, 8:28pm UTC](https://discourse.vtk.org/t/using-vtkarraycalculator-to-multiply-a-vector-array-by-a-single-scalar-value/12594/1 "2023-10-31T20:28:09Z")

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It is clear how to use vtkArrayCalculator to multiply a vector array (point based) times a single scalar value. For example OutputVector = InputVector \* 2.3.

But is it possible to define other variables instead of explicitly writing 2.3. For example:

a = 1.2  
b = sqrt(a)  
OutputVector = InputVector\*b

.