Applying Logarithmic Transformations for Demand Prediction

Hi,

I'm currently working on modifying an existing notebook titled "Part One: Avocado Pricing and Supply Using Mathematical Optimization" available at https://colab.research.google.com/github/Gurobi/modeling-examples/blob/master/price_optimization/price_optimization_gcl.ipynb

My objective is to apply logarithmic transformations to the price and units_sold variables, but I'm facing an issue when trying to create an expression for the predicted demand. I would greatly appreciate any assistance or suggestions on how to resolve this issue. 

My code:

d = {r: np.exp(coef_dict['Intercept'] + coef_dict['log_price']*np.log(p[r]) + coef_dict['C(region)[T.%s]'%r] + coef_dict['year_index']*(year-2015) + coef_dict['peak']*peak_or_not) for r in R}

for r in R:

    print(d[r])

---------------------------------------------------------------------------

AttributeError                            Traceback (most recent call last)

src/gurobipy/var.pxi in gurobipy.Var.__getattr__()

src/gurobipy/var.pxi in gurobipy.Var.getAttr()

src/gurobipy/attrutil.pxi in gurobipy.__getattr()

src/gurobipy/attrutil.pxi in gurobipy.__getattrinfo()

AttributeError: 'gurobipy.Var' object has no attribute 'log'

The above exception was the direct cause of the following exception:

TypeError                                 Traceback (most recent call last)

<ipython-input-45-741ec6d3f402> in <cell line: 2>()

      1 # Calcular la demanda utilizando el modelo ajustado y las variables transformadas

----> 2 d = {r: np.exp(coef_dict['Intercept'] + coef_dict['log_price']*np.log(p[r]) + coef_dict['C(region)[T.%s]'%r] + coef_dict['year_index']*(year-2015) + coef_dict['peak']*peak_or_not) for r in R}

      3 

      4 for r in R:

      5     print(d[r])

<ipython-input-45-741ec6d3f402> in <dictcomp>(.0)

      1 # Calcular la demanda utilizando el modelo ajustado y las variables transformadas

----> 2 d = {r: np.exp(coef_dict['Intercept'] + coef_dict['log_price']*np.log(p[r]) + coef_dict['C(region)[T.%s]'%r] + coef_dict['year_index']*(year-2015) + coef_dict['peak']*peak_or_not) for r in R}

      3 

      4 for r in R:

      5     print(d[r])

TypeError: loop of ufunc does not support argument 0 of type Var which has no callable log method