# DAQmx Compute Reverse Polynomial Coefficients (G Dataflow)

Last Modified: January 11, 2018

Computes a set of coefficients for a polynomial that approximates the inverse of the polynomial with the coefficients you specify with the coefficients input. This VI generates a table of x versus y values over the range of x. This VI then finds a polynomial fit, using the least squares method to compute a polynomial that computes x when given a value for y.  ## coefficients

coefficients is the array of coefficients for the polynomial that computes y given a value of x. Each element of the array corresponds to a term of the equation.

For example, if index three of the array is 9, the fourth term of the equation is 9x^3. ## maximum valid value of x

maximum valid value of x is the maximum value of x for which you use the polynomial. This is the largest value of x for which the node generates a y value in the table. ## minimum valid value of x

minimum valid value of x is the minimum value of x for which you use the polynomial. This is the smallest value of x for which the node generates a y value in the table. ## number of points to compute within x range

number of points to compute within x range is the number of points in the table of x versus y values. The VI spaces the values evenly between minimum valid value of x and maximum valid value of x. ## error in

error in describes error conditions that occur before this node runs. This input provides standard 'error in' functionality. ## reverse polynomial order

reverse polynomial order is the order of the reverse polynomial to compute. For example, an input of 3 indicates a 3rd order polynomial. A value of -1 indicates a reverse polynomial of the same order as the forward polynomial. ## reverse coefficients

reverse coefficients is the array of coefficients for the reverse polynomial. Each element of the array corresponds to a term of the equation. For example, if index three of the array is 9, the fourth term of the equation is 9y^3. ## error out

error out contains error information. If error in indicates that an error occurred before this node ran, error out contains the same error information. Otherwise, error out describes the error status that this node produces.

Where This Node Can Run:

Desktop OS: Windows

FPGA: LabVIEW NXG does not support FPGA devices

Web Server: Not supported in VIs that run in a web application