# 3.1. Growth¶

There is 2 different implementations of the growth module.

## 3.1.1. SoleGrowthAction.java¶

In this implementation, the length increment only depends on temperature and is given by:

$\Delta L = C_1 \times T^{C_2} \times \Delta t$

with $$L$$ the length, $$T$$ the temperature and $$\Delta t$$ the time step in days, and $$C_1$$ and $$C_2$$ are parameters (c1 and c2 respectively).

The temperature field is provided by the temperature_field parameter.

## 3.1.2. LinearGrowthAction.java¶

In this implementation, the length increment is provided as follows:

$\Delta L = C_1 + C_2 \times \dfrac{F}{F + K_S} \times max(T, T_{thres}) \times \Delta t$

where $$\Delta t$$ is the time-step (in days), $$C_1$$ and $$C_2$$ are parameters (coeff1 and coeff2), $$T_{thres}$$ is a temperature threshold (threshold_temp parameter), $$F$$ is the food quantity and $$K_S$$ is a half-saturation constant (half_saturation parameter). If the latter is not defined or equals 0, $$Q$$ is assumed to be $$1$$.

The name of the food and temperature variables are provided by the food_field and temperature_field parameters.