DoubleExponential¶
- class DoubleExponential(up=True, meanstress=1, cutoff=0.999)[source]¶
Double Exponential response function with 4 parameters A, alpha, a1 and a2.
- Parameters
up (bool or None, optional) – indicates whether a positive stress will cause the head to go up (True, default) or down (False), if None the head can go both ways.
meanstress (float) – mean value of the stress, used to set the initial value such that the final step times the mean stress equals 1
cutoff (float) – proportion after which the step function is cut off. default is 0.999.
Notes
The impulse response function may be written as:
\[\theta(t) = A (1 - \alpha) e^{-t/a_1} + A \alpha e^{-t/a_2}\]
Methods¶
Method to return the block function. |
|
Get initial parameters and bounds. |
|
Internal method to determine the times at which to evaluate the step-response, from t=0. |
|
Method to get the response time for a certain cutoff. |
|
Method to return the step function. |