# pyblp.options¶

Global options.

pyblp.options.digits

Number of digits displayed by status updates. The default number of digits is 10. The number of digits can be changed to, for example, 20, with pyblp.options.digits = 20.

Type

int

pyblp.options.verbose

Whether to output status updates. By default, verbosity is turned on. Verbosity can be turned off with pyblp.options.verbose = False.

Type

bool

pyblp.options.verbose_output

Function used to output status updates. The default function is simply print. The function can be changed, for example, to include an indicator that statuses are from this package, with pyblp.verbose_output = lambda x: print(f"pyblp: {x}").

Type

callable

pyblp.options.dtype

The data type used for internal calculations, which is by default numpy.float64. The other recommended option is numpy.longdouble, which is the only extended precision floating point type currently supported by NumPy. Although this data type will be used internally, numpy.float64 will be used when passing arrays to optimization and fixed point routines, which may not support extended precision. The library underlying scipy.linalg, which is used for matrix inversion, may also use numpy.float64.

One instance in which extended precision can be helpful in the BLP problem is when there are a large number of near zero choice probabilities with small integration weights, which, under standard precision are called zeros when in aggregate they are nonzero. For example, Skrainka (2012) finds that using long doubles is sufficient to solve many utility floating point problems.

The precision of numpy.longdouble depends on the platform on which NumPy is installed. If the platform in use does not support extended precision, using numpy.longdouble may lead to unreliably results. For example, on Windows, NumPy is usually compiled such that numpy.longdouble often behaves like numpy.float64. Precisions can be compared with numpy.finfo by running np.finfo(np.float64) and np.finfo(np.longdouble). For more information, refer to this discussion.

If extended precisions is supported, the data type can be switched with pyblp.options.dtype = np.longdouble. On Windows, it is often easier to install Linux in a virtual machine than it is to build NumPy from source with a non-standard compiler.

Type

dtype

pyblp.options.collinear_atol

Absolute tolerance for detecting collinear columns in each matrix of product characteristics and instruments: $$X_1$$, $$X_2$$, $$X_3$$, $$Z_D$$, and $$Z_S$$.

Each matrix is decomposed into a $$QR$$ decomposition and an error is raised for any column whose diagonal element in $$R$$ has a magnitude less than collinear_atol + collinear_rtol * sd where sd is the column’s standard deviation.

The default absolute tolerance is 1e-14. To disable collinearity checks, set pyblp.options.collinear_atol = pyblp.options.collinear_rtol = 0.

Type

float

pyblp.options.collinear_rtol

Relative tolerance for detecting collinear columns, which is by default also 1e-14.

Type

float