From b1420fd67715803c18f5530c245fac4772804611 Mon Sep 17 00:00:00 2001
From: Justin Staples <staplejw@mcmaster.ca>
Date: Mon, 9 Apr 2018 10:40:37 -0400
Subject: [PATCH 1/3] adding test for cauchy transformation to student's t

---
 haskell/Tests/RoundTrip.hs                    |  6 ++++++
 tests/RoundTrip2/t_cauchy_to_students_t.0.hk  | 14 +++++++++++++
 .../t_cauchy_to_students_t.expected.hk        | 21 +++++++++++++++++++
 3 files changed, 41 insertions(+)
 create mode 100644 tests/RoundTrip2/t_cauchy_to_students_t.0.hk
 create mode 100644 tests/RoundTrip2/t_cauchy_to_students_t.expected.hk

diff --git a/haskell/Tests/RoundTrip.hs b/haskell/Tests/RoundTrip.hs
index 810746e3..ab5c0bd7 100644
--- a/haskell/Tests/RoundTrip.hs
+++ b/haskell/Tests/RoundTrip.hs
@@ -211,6 +211,11 @@ testStdChiSqRelations = test [
     "t_rayleigh_to_stdChiSq"     ~: testConcreteFiles "tests/RoundTrip2/t_rayleigh_to_stdChiSq.0.hk" "tests/RoundTrip2/t_rayleigh_to_stdChiSq.expected.hk"        
     ]
 
+testCauchyRelations :: Test 
+testCauchyRelations = test [
+    "t_cauchy_to_students_t" ~: testConcreteFiles "tests/RoundTrip2/t_cauchy_to_students_t.0.hk" "tests/RoundTrip2/t_cauchy_to_students_t.expected.hk"
+    ]
+
 testOther :: Test
 testOther = test [
     "t82"              ~: testConcreteFiles "tests/RoundTrip/t82.0.hk" "tests/RoundTrip/t82.expected.hk",
@@ -253,6 +258,7 @@ allTests = test
     , testMeasureNat
     , testMeasureInt
     , testStdChiSqRelations
+    , testCauchyRelations
     , testOther
     ]
 
diff --git a/tests/RoundTrip2/t_cauchy_to_students_t.0.hk b/tests/RoundTrip2/t_cauchy_to_students_t.0.hk
new file mode 100644
index 00000000..90cfd748
--- /dev/null
+++ b/tests/RoundTrip2/t_cauchy_to_students_t.0.hk
@@ -0,0 +1,14 @@
+def stdNormal():
+	p <~ normal(0, 1)
+	return p
+
+def stdCauchy():
+	X1 <~ stdNormal()
+	X2 <~ stdNormal()
+	return X1/X2
+
+def cauchy(a real, alpha prob):
+	X <~ stdCauchy()
+	return a + alpha*X
+
+cauchy(0, 1)
\ No newline at end of file
diff --git a/tests/RoundTrip2/t_cauchy_to_students_t.expected.hk b/tests/RoundTrip2/t_cauchy_to_students_t.expected.hk
new file mode 100644
index 00000000..d82c6fd0
--- /dev/null
+++ b/tests/RoundTrip2/t_cauchy_to_students_t.expected.hk
@@ -0,0 +1,21 @@
+def chiSq_iid(n nat, mean real, stdev prob):
+	q <~ plate _ of n: normal(mean,stdev)
+	return summate i from 0 to size(q): 
+		((q[i]-mean)/stdev)^2
+
+def standardChiSq(n nat):
+	chiSq_iid(n,0,1)
+
+def standardChi(n nat):
+	q <~ standardChiSq(n)
+	return sqrt(real2prob(q))
+
+def nonCentralT(n nat, delta prob):
+	U <~ normal(0,1)
+	X <~ standardChi(n)
+	return (U + delta)*sqrt(n)/(X)
+
+def t(n nat):
+	return nonCentralT(n,0)
+
+t(1)

From 70d80bc8e9293ca5eaf8d6ede893c870e7c0ab84 Mon Sep 17 00:00:00 2001
From: Justin Staples <staplejw@mcmaster.ca>
Date: Tue, 24 Apr 2018 00:00:37 -0400
Subject: [PATCH 2/3] fixing test case

---
 tests/RoundTrip2/t_cauchy_to_students_t.expected.hk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/RoundTrip2/t_cauchy_to_students_t.expected.hk b/tests/RoundTrip2/t_cauchy_to_students_t.expected.hk
index d82c6fd0..b0af40d3 100644
--- a/tests/RoundTrip2/t_cauchy_to_students_t.expected.hk
+++ b/tests/RoundTrip2/t_cauchy_to_students_t.expected.hk
@@ -16,6 +16,6 @@ def nonCentralT(n nat, delta prob):
 	return (U + delta)*sqrt(n)/(X)
 
 def t(n nat):
-	return nonCentralT(n,0)
+	nonCentralT(n,0)
 
 t(1)

From d8b9ad7cf6637580a46edc8e451998809c11d94a Mon Sep 17 00:00:00 2001
From: Mahmoud Khattab <khattm@mcmaster.ca>
Date: Tue, 24 Apr 2018 13:57:35 -0400
Subject: [PATCH 3/3] Fix

---
 tests/RoundTrip/t_cauchy_to_students_t.expected.hk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/RoundTrip/t_cauchy_to_students_t.expected.hk b/tests/RoundTrip/t_cauchy_to_students_t.expected.hk
index 428e16d1..b7c3f5e7 100644
--- a/tests/RoundTrip/t_cauchy_to_students_t.expected.hk
+++ b/tests/RoundTrip/t_cauchy_to_students_t.expected.hk
@@ -1,4 +1,4 @@
 #t(1)
 U <~ normal(+0/1,1/1)
 X <~ normal(+0/1,1/1)
-return U/abs(X)
+return U/X