# Hantush#

The Hantush well function, using the standard A, a, b parameters.

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 is:

$\theta(t) = \frac{A}{2t \text{K}_0\left(2\sqrt{b} \right)} \exp(-t/a - ab/t)$

where A, a, and b are parameters.

The implementation used here is explained in Veling and Maas (2010).

References

veling_2010

Veling, E. J. M., & Maas, C. (2010). Hantush well function revisited. Journal of hydrology, 393(3), 381-388.

## Methods#

 __init__ block Method to return the block function. gain get_init_parameters Get initial parameters and bounds. get_t Internal method to determine the times at which to evaluate the step-response, from t=0. get_tmax Method to get the response time for a certain cutoff. impulse Method to return the impulse response function. numba_step numpy_step quad_step step Method to return the step function.