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19 changes: 12 additions & 7 deletions lectures/_toc.yml
Original file line number Diff line number Diff line change
Expand Up @@ -72,16 +72,21 @@ parts:
- file: jv
- file: odu
- file: mccall_q
- caption: Introduction to Optimal Savings
numbered: true
chapters:
- file: os
- file: os_numerical
- file: os_stochastic
- file: os_time_iter
- file: os_egm
- file: os_egm_jax
- caption: Household Problems
numbered: true
chapters:
- file: cake_eating
- file: cake_eating_numerical
- file: cake_eating_stochastic
- file: cake_eating_time_iter
- file: cake_eating_egm
- file: cake_eating_egm_jax
- file: ifp
- file: ifp_discrete
- file: ifp_opi
- file: ifp_egm
- file: ifp_advanced
- caption: LQ Control
numbered: true
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21 changes: 9 additions & 12 deletions lectures/ifp_advanced.md
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Expand Up @@ -17,7 +17,7 @@ kernelspec:
</div>
```

# {index}`The Income Fluctuation Problem II: Stochastic Returns on Assets <single: The Income Fluctuation Problem II: Stochastic Returns on Assets>`
# {index}`The Income Fluctuation Problem IV: Stochastic Returns on Assets <single: The Income Fluctuation Problem IV: Stochastic Returns on Assets>`

```{contents} Contents
:depth: 2
Expand All @@ -34,7 +34,7 @@ tags: [hide-output]

## Overview

In this lecture, we continue our study of the {doc}`income fluctuation problem <ifp>`.
In this lecture, we continue our study of the income fluctuation problem described in {doc}`ifp_egm`.

While the interest rate was previously taken to be fixed, we now allow
returns on assets to be state-dependent.
Expand Down Expand Up @@ -112,7 +112,7 @@ where

Let $P$ represent the Markov matrix for the chain $\{Z_t\}_{t \geq 0}$.

Our assumptions on preferences are the same as our {doc}`previous lecture <ifp>` on the income fluctuation problem.
Our assumptions on preferences are the same as in {doc}`ifp_egm`.

As before, $\mathbb E_z \hat X$ means expectation of next period value
$\hat X$ given current value $Z = z$.
Expand Down Expand Up @@ -160,8 +160,7 @@ the IID and CRRA environment of {cite}`benhabib2015`.

### Optimality

Let the class of candidate consumption policies $\mathscr C$ be defined
{doc}`as before <ifp>`.
Let the class of candidate consumption policies $\mathscr C$ be defined as in {doc}`ifp_egm`.

In {cite}`ma2020income` it is shown that, under the stated assumptions,

Expand All @@ -182,8 +181,7 @@ In the present setting, the Euler equation takes the form
\right\}
```

(Intuition and derivation are similar to our {doc}`earlier lecture <ifp>` on
the income fluctuation problem.)
(Intuition and derivation are similar to {doc}`ifp_egm`.)

We again solve the Euler equation using time iteration, iterating with a
Coleman--Reffett operator $K$ defined to match the Euler equation
Expand All @@ -197,8 +195,7 @@ Coleman--Reffett operator $K$ defined to match the Euler equation
### A Time Iteration Operator

Our definition of the candidate class $\sigma \in \mathscr C$ of consumption
policies is the same as in our {doc}`earlier lecture <ifp>` on the income
fluctuation problem.
policies is the same as in {doc}`ifp_egm`.

For fixed $\sigma \in \mathscr C$ and $(a,z) \in \mathbf S$, the value
$K\sigma(a,z)$ of the function $K\sigma$ at $(a,z)$ is defined as the
Expand Down Expand Up @@ -251,7 +248,7 @@ convergence (as measured by the distance $\rho$).
### Using an Endogenous Grid

In the study of that model we found that it was possible to further
accelerate time iteration via the {doc}`endogenous grid method <cake_eating_egm>`.
accelerate time iteration via the {doc}`endogenous grid method <os_egm>`.

We will use the same method here.

Expand Down Expand Up @@ -578,7 +575,7 @@ In contrast, when $z=1$ (good state), higher expected future income allows the h
Let's try to get some idea of what will happen to assets over the long run
under this consumption policy.

As with our {doc}`earlier lecture <ifp>` on the income fluctuation problem, we
As in {doc}`ifp_egm`, we
begin by producing a 45 degree diagram showing the law of motion for assets

```{code-cell} python3
Expand Down Expand Up @@ -911,7 +908,7 @@ The JAX implementation provides several advantages:
```{exercise}
:label: ifpa_ex1

Let's repeat our {ref}`earlier exercise <ifp_ex2>` on the long-run
Let's repeat our {ref}`earlier exercise <ifp_egm_ex2>` on the long-run
cross sectional distribution of assets.

In that exercise, we used a relatively simple income fluctuation model.
Expand Down
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