biogeme.expressions.numeric_expressions module

Arithmetic expressions accepted by Biogeme: numeric expressions

author:

Michel Bierlaire

date:

Sat Sep 9 15:27:17 2023

class biogeme.expressions.numeric_expressions.Numeric(value)

Bases: Expression

Numerical expression for a simple number

Parameters:

value (float | int | bool)

getValue()

Warning

This function is deprecated. Use get_value() instead.

Kept for backward compatibility

Return type:

float

get_signature()

The signature of a string characterizing an expression.

This is designed to be communicated to C++, so that the expression can be reconstructed in this environment.

The list contains the following elements:

1. the name of the expression between < >

2. the id of the expression between { }

3. the value, preceeded by a comma.

Consider the following expression:

\[2 \beta_1 V_1 - \frac{\exp(-\beta_2 V_2) }{ \beta_3 (\beta_2 \geq \beta_1)}.\]

It is defined as:

2 * beta1 * Variable1 - expressions.exp(-beta2*Variable2) /
    (beta3 * (beta2 >= beta1))

And its signature is:

[b'<Numeric>{4780527008},2',
 b'<Beta>{4780277152}"beta1"[0],0,0',
 b'<Times>{4780526952}(2),4780527008,4780277152',
 b'<Variable>{4511837152}"Variable1",5,2',
 b'<Times>{4780527064}(2),4780526952,4511837152',
 b'<Beta>{4780277656}"beta2"[0],1,1',
 b'<UnaryMinus>{4780527120}(1),4780277656',
 b'<Variable>{4511837712}"Variable2",6,3',
 b'<Times>{4780527176}(2),4780527120,4511837712',
 b'<exp>{4780527232}(1),4780527176',
 b'<Beta>{4780277264}"beta3"[1],2,0',
 b'<Beta>{4780277656}"beta2"[0],1,1',
 b'<Beta>{4780277152}"beta1"[0],0,0',
 b'<GreaterOrEqual>{4780527288}(2),4780277656,4780277152',
 b'<Times>{4780527344}(2),4780277264,4780527288',
 b'<Divide>{4780527400}(2),4780527232,4780527344',
 b'<Minus>{4780527456}(2),4780527064,4780527400']

Returns:

list of the signatures of an expression and its children.

Return type:

list(string)

get_value()

Evaluates the value of the expression

Returns:

value of the expression

Return type:

float

value

numeric value