From 3b83aad6bdbe9fd36e26e2e89f125857d4a90456 Mon Sep 17 00:00:00 2001
From: Josh Burman <jburman@yas.getyardstick.com>
Date: Fri, 29 Oct 2021 19:19:12 +0000
Subject: [PATCH] added iif and tif functions

---
 app/lib/irt/item_information_function.py | 14 ++++++++++++++
 app/lib/irt/test_information_function.py | 16 ++++++++++++++++
 app/main.py                              |  2 +-
 app/models/item.py                       |  1 +
 app/services/loft_service.py             |  3 +++
 5 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/app/lib/irt/item_information_function.py b/app/lib/irt/item_information_function.py
index e69de29..f38512e 100644
--- a/app/lib/irt/item_information_function.py
+++ b/app/lib/irt/item_information_function.py
@@ -0,0 +1,14 @@
+from lib.irt.models.three_parameter_logistic import ThreeParameterLogistic
+
+class ItemInformationFunction():
+  def __init__(self, irt_model):
+    self.model_data = irt_model
+
+  def calculate(self, **kwargs):
+    if self.model_data.model == '3PL':
+      p = ThreeParameterLogistic(self.model_data, kwargs).result()
+      q = 1 - p
+      return self.model_data.a_param**2 * ((q / p) * ((p - (self.model_data.c_param**2)) / (1 - (self.model_data.c_param**2))))
+    else:
+      # potentially error out
+      return None
diff --git a/app/lib/irt/test_information_function.py b/app/lib/irt/test_information_function.py
index e69de29..aef771d 100644
--- a/app/lib/irt/test_information_function.py
+++ b/app/lib/irt/test_information_function.py
@@ -0,0 +1,16 @@
+from lib.irt.item_information_function import ItemInformationFunction
+
+class TestInformationFunction():
+  def __init__(self, irt_model):
+    self.irt_model = irt_model
+    self.iif = ItemInformationFunction(irt_model)
+
+  def calculate(self, items, **kwargs):
+    sum = 0
+
+    for item in items:
+      result = self.iif.calculate(b_param=item.b_param, theta=kwargs['theta'])
+      item.iif = result
+      sum += item.iif
+
+    return sum
diff --git a/app/main.py b/app/main.py
index 1308bda..b05b631 100644
--- a/app/main.py
+++ b/app/main.py
@@ -8,7 +8,7 @@ from sqs_listener.daemon import Daemon
 
 print("Starting Solver Service (v0.3.1)...")
 
-# # listen to the solver queue
+# listen to the solver queue
 while True:
   msg = aws_helper.receive_message(os.environ['SOLVER_SQS_INGEST_QUEUE'])
 
diff --git a/app/models/item.py b/app/models/item.py
index eca5421..d94c5cd 100644
--- a/app/models/item.py
+++ b/app/models/item.py
@@ -8,3 +8,4 @@ class Item(BaseModel):
   attributes: List[Attribute]
   b_param: int
   irf: float = 0.00
+  iif: float = 0.00
diff --git a/app/services/loft_service.py b/app/services/loft_service.py
index f67f0f3..d189958 100644
--- a/app/services/loft_service.py
+++ b/app/services/loft_service.py
@@ -9,6 +9,9 @@ from models.solver_run import SolverRun
 from models.solution import Solution
 from models.form import Form
 
+from lib.irt.test_response_function import TestResponseFunction
+from lib.irt.test_information_function import TestInformationFunction
+
 from services.base import Base
 
 class LoftService(Base):