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Orbits/Code/successful_recursion.ipynb

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{
"cells": [
{
"cell_type": "code",
"execution_count": 1,
"id": "planned-choir",
"metadata": {
"tags": []
},
"outputs": [],
"source": [
"import torch\n",
"from torch.autograd.functional import jacobian\n",
"import itertools"
]
},
{
"cell_type": "markdown",
"id": "japanese-split",
"metadata": {},
"source": [
"# Setup Functions\n",
"## General CompositionFunctions"
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "final-contest",
"metadata": {},
"outputs": [],
"source": [
"### Set up functions to compose functions \n",
"# These functions will \n",
"# - compose two functions together\n",
"# - compose a function to itself n times.\n",
"\n",
"def compose(f,g):\n",
" return lambda *args: f(g(*args))\n",
"\n",
"def compose_recursive_functions(fn,n):\n",
" #takes a function fn and composes it with itself n times\n",
" #Returns each of the iterations of the functions.\n",
" \n",
" #Set base conditions\n",
" out_func = None\n",
" out_func_list =[]\n",
"\n",
" #build the compositions of functions\n",
" for f in itertools.repeat(fn, n):\n",
" #if first iteration\n",
" if out_func == None:\n",
" out_func = f\n",
" else:\n",
" out_func = compose(f,out_func)\n",
"\n",
" #append the ou\n",
" out_func_list.append(out_func)\n",
" \n",
" return out_func_list"
]
},
{
"cell_type": "markdown",
"id": "specific-centre",
"metadata": {},
"source": [
"## Setup functions related to the problem"
]
},
{
"cell_type": "code",
"execution_count": 15,
"id": "grand-jesus",
"metadata": {},
"outputs": [],
"source": [
"### Background functions\n",
"\n",
"\n",
"def survival(stock, debris):\n",
" #TODO: ACTUALLY DERIVE A SURVIVAL FUNCTION. THIS IS JUST A PLACEHOLDER. PROBABLY SHOULD BE AN EXPONENTIAL DISTRIBUTION\n",
"\n",
" return 1 - torch.exp(-SCALING * stock-debris)\n",
"\n",
"def test_launch(stock, debris):\n",
" return torch.ones(5, requires_grad=True)\n",
"\n",
"def laws_of_motion(stock, debris, launches):\n",
" \n",
" new_stock = stock*survival(stock,debris) + launches#(stock,debris) #TODO: Launches will become a function (neural network)\n",
" \n",
" #TODO: Currently Ignoring autocatalysis\n",
" new_debris = (1-DELTA)*debris + LAUNCH_DEBRIS_RATE * launches.sum() + COLLISION_DEBRIS_RATE*(1-survival(stock,debris)) @ stock\n",
" \n",
" return (new_stock, new_debris)\n",
"\n",
"#This is not a good specification of the profit function, but it will work for now.\n",
"#similar to Rao and Rondina's\n",
"def profit(x):\n",
" return UTIL_WEIGHTS @ x"
]
},
{
"cell_type": "code",
"execution_count": 16,
"id": "military-tunnel",
"metadata": {},
"outputs": [],
"source": [
"def single_transition(item_to_iterate, laws_motion, profit,launch, stocks, debris ):\n",
" #TODO: change launch from a direct tensor, to a function.\n",
" \n",
" #Calculate the inverse\n",
" bA = BETA * jacobian(laws_motion, (stocks,debris,launch))[0][0]\n",
" #TODO: figure out some diagnostics for this section\n",
" \n",
" \n",
" return bA.inverse() @ (item_to_iterate - jacobian(profit,stocks))\n",
"\n",
"# This function wraps the single transition and handles updating dates etc.\n",
"def transition_wrapper(data_in):\n",
" #unpack states and functions\n",
" stocks, debris,profit, launch, laws_motion, item_to_transition = data_in\n",
" \n",
" #Calculate new states\n",
" new_stocks, new_debris = laws_motion(stocks,debris,launch)\n",
" \n",
" #WARNING: RECURSION: You may break your head...\n",
" #This gets the transition of the value function derivatives over time.\n",
" transitioned = single_transition(\n",
" item_to_transition, #item to iterate, i.e. the derivatives of the value function\n",
" #functions\n",
" laws_motion, \n",
" profit, \n",
" launch, #TODO: reimplement with launch as a function\n",
" stocks, debris #states\n",
" )\n",
" \n",
" #collects the data back together for return, including the updated state variables\n",
" data_out = new_stocks, new_debris, profit, launch, laws_motion, transitioned\n",
" \n",
" return data_out"
]
},
{
"cell_type": "markdown",
"id": "hindu-recruitment",
"metadata": {},
"source": [
"# Actual calculations"
]
},
{
"cell_type": "code",
"execution_count": 17,
"id": "metric-bruce",
"metadata": {},
"outputs": [],
"source": [
"#set states\n",
"stocks = torch.ones(5)\n",
"#Last one is different\n",
"stocks[-1] = 0.5\n",
"#now add the tracking requirement in place\n",
"stocks.requires_grad_()\n",
"\n",
"#Setup Debris\n",
"debris = torch.tensor([2.2],requires_grad=True)\n",
"\n",
"#CHANGE LATER: Launch is currently a value, should be a function (i.e. neural network)\n",
"launch = torch.ones(5, requires_grad=True)\n",
"\n",
"#compose the functions together.\n",
"base_data = (stocks,debris, profit, launch, laws_of_motion, torch.ones(5, requires_grad=True))\n",
"\n",
"#Parameters\n",
"SCALING = torch.ones(5)\n",
"DELTA = 0.9 \n",
"LAUNCH_DEBRIS_RATE = 0.005\n",
"COLLISION_DEBRIS_RATE = 0.0007\n",
"UTIL_WEIGHTS = torch.tensor([1,-0.2,0,0,0])\n",
"BETA = 0.95"
]
},
{
"cell_type": "code",
"execution_count": 21,
"id": "musical-neighbor",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"(tensor([1.9592, 1.9592, 1.9592, 1.9592, 1.4664], grad_fn=<AddBackward0>), tensor([0.2451], grad_fn=<AddBackward0>), <function profit at 0x7f000d27fdc0>, tensor([1., 1., 1., 1., 1.], requires_grad=True), <function laws_of_motion at 0x7f003e976b80>, tensor([0.0000, 1.2632, 1.0526, 1.0526, 1.0892], grad_fn=<MvBackward>))\n",
"(tensor([2.7431, 2.7431, 2.7431, 2.7431, 2.2016], grad_fn=<AddBackward0>), tensor([0.0503], grad_fn=<AddBackward0>), <function profit at 0x7f000d27fdc0>, tensor([1., 1., 1., 1., 1.], requires_grad=True), <function laws_of_motion at 0x7f003e976b80>, tensor([-0.9519, 1.3928, 1.0020, 1.0020, 1.0575], grad_fn=<MvBackward>))\n",
"(tensor([3.5752, 3.5752, 3.5752, 3.5752, 2.9700], grad_fn=<AddBackward0>), tensor([0.0307], grad_fn=<AddBackward0>), <function profit at 0x7f000d27fdc0>, tensor([1., 1., 1., 1., 1.], requires_grad=True), <function laws_of_motion at 0x7f003e976b80>, tensor([-1.8565, 1.5150, 0.9530, 0.9530, 0.9882], grad_fn=<MvBackward>))\n",
"(tensor([4.4781, 4.4781, 4.4781, 4.4781, 3.8222], grad_fn=<AddBackward0>), tensor([0.0284], grad_fn=<AddBackward0>), <function profit at 0x7f000d27fdc0>, tensor([1., 1., 1., 1., 1.], requires_grad=True), <function laws_of_motion at 0x7f003e976b80>, tensor([-2.8103, 1.6872, 0.9376, 0.9376, 0.9474], grad_fn=<MvBackward>))\n",
"(tensor([5.4286, 5.4286, 5.4286, 5.4286, 4.7409], grad_fn=<AddBackward0>), tensor([0.0280], grad_fn=<AddBackward0>), <function profit at 0x7f000d27fdc0>, tensor([1., 1., 1., 1., 1.], requires_grad=True), <function laws_of_motion at 0x7f003e976b80>, tensor([-3.8626, 1.9131, 0.9505, 0.9505, 0.9408], grad_fn=<MvBackward>))\n"
]
}
],
"source": [
"#calculate results for first 5 iterations\n",
"for f in compose_recursive_functions(transition_wrapper,5):\n",
" result = f(base_data)\n",
" print(result)\n",
" #need to write down what this is."
]
},
{
"cell_type": "markdown",
"id": "portable-placement",
"metadata": {},
"source": [
"# Notes on work so far\n",
"the issue below was resolved by choosing a different loss function. The point of needing to do a search over the determinant of A still holds.\n",
">>\n",
"Note how this fails on the last few iterations.\n",
"I need to get better model functions (profit, laws_of_motion, etc) together to test this out.\n",
"Alternatively, I can check for areas where the determinant of $A$ is zero, possibly by doing some sort of grid search?\n",
"Maybe with a standard RBC model?\n",
"\n",
"Also, maybe I can create a `Model` class that upon construction will capture the necesary constants, functions, etc.\n",
"\n",
"I need to change the launch to be a neural network function that takes two inputs."
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "frequent-subcommittee",
"metadata": {},
"outputs": [],
"source": []
}
],
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