Simulating Default with Bernoulli Distribution

Overview


The Bernoulli Model of Pd can be used to simlulate default.

Bernoulli Distribution



The simplest way to simulate a default over a given time frame is to model the default as a Bernoulli variable. (see the Bernoulli Distribution). A Bernoulli variable is a random variable that takes only one of two values, with probabilities p, and (1-p).

In the case of default, one could label default of asset i in a portfolio as
{% Default = D_i %}
Then the probability of default is labeled {% PD_i %}

Implementation



A simple way to simulate a 0-1 event such as default is to simulate a number from 0 to 1 with a uniform distribution, and if the simulated number is less than the probability of default, then take that as a default, otherwise take it to be no default.


//probability of default
let pd = 0.01;
let di;
let u = Math.random();
if(u<pd) di=1;
else di = 0;

					

Bernoulli API



The bernoulli module can also be used to simulate default.


let bl = await import('/lib/statistics/distributions/bernoulli/v1.0.0/bernoulli.mjs');

//probability of default
let pd = 0.01;
let di = bl.random(pd);

					


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