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DETREND detrends the input analysis object using a polynomial of degree N. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% DESCRIPTION: DETREND detrends the input analysis object using a polynomial of degree N. CALL: b = detrend(a1,a2,a3,..., pl) INPUTS: aN - a list of analysis objects pl - a parameter list OUTPUTS: b - array of analysis objects If the last input argument is a parameter list (plist) it is used. The following parameters are recognised. NOTE: detrend uses two possible algorithms. By default, or if the order is higher than 10, then a MATLAB code is used which is typically much slower, but giving coefficents that can be easily called within pest/eval. A fast C-code implementation is also available for orders less than 11. You can force the use of the C code using a plist option. When interpreting the resulting coefficients, you must be clear which algorithm was used. For the C-code algorithm, the coefficients are scaled from the original by z = 2.*ii/(n-1)-1; such that the functional form (for a three-coefficient example) that is subtracted from the data can be recovered with: fitted_c = c.y(3).*z.^2 + c.y(2).*z + c.y(1); The procinfo field of the output AOs is filled with the following key/value pairs: 'COEFFS' - pest object with coefficients describing the subtracted trend function Note that they correspond to physical trend coefficents only if using the (default) option 'M-FILE ONLY'. In the case of using the (faster) C-code algorithm, see the note above. Parameters Description %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
| Method Details | |
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| Access | public |
| Defining Class | ao |
| Sealed | 0 |
| Static | 0 |
| Sets for this method … |
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| Default |
Default |
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| no description | |||
| Key | Default Value | Options | Description |
| detrend | |||
| ORDER, N | 1 |
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The order of detrending:
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| M-FILE ONLY | 1 |
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Using M-file call |
| TIMES | [] | none | Evaluate the trend only on a limited data segment, and then detrend the whole data set. An array of start/stop times to split by. The times should be relativeto the object reference time (t0). |
Example |
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| plist('ORDER', [1], 'M-FILE ONLY', [true], 'TIMES', [[]]) |
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| Some information of the method ao/detrend are listed below: | |
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| Class name | ao |
| Method name | detrend |
| Category | Signal Processing |
| Package name | ltpda |
| Can be used as modifier | 1 |
| Supported numeric types | {'double'} |
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Method: ao/detectOutliers | Method: ao/dft | ![]() |
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