From 20cc336a7a20ec3f6cec5bfba67242f13342babf Mon Sep 17 00:00:00 2001
From: Nicolas <n.durrande@sheffield.ac.uk>
Date: Mon, 21 Jan 2013 13:29:25 +0000
Subject: [PATCH] added periodic kernels

---
 GPy/kern/__init__.py     |  2 +-
 GPy/kern/constructors.py | 57 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/GPy/kern/__init__.py b/GPy/kern/__init__.py
index 4a36d6d0..eae717be 100644
--- a/GPy/kern/__init__.py
+++ b/GPy/kern/__init__.py
@@ -2,5 +2,5 @@
 # Licensed under the BSD 3-clause license (see LICENSE.txt)
 
 
-from constructors import rbf, Matern32, Matern52, exponential, linear, white, bias, finite_dimensional, spline, Brownian, linear_ARD, rbf_sympy, sympykern
+from constructors import rbf, Matern32, Matern52, exponential, linear, white, bias, finite_dimensional, spline, Brownian, linear_ARD, rbf_sympy, sympykern, periodic_exponential, periodic_Matern32, periodic_Matern52
 from kern import kern
diff --git a/GPy/kern/constructors.py b/GPy/kern/constructors.py
index ab39fcb2..49639711 100644
--- a/GPy/kern/constructors.py
+++ b/GPy/kern/constructors.py
@@ -16,6 +16,9 @@ from bias import bias as biaspart
 from finite_dimensional import finite_dimensional as finite_dimensionalpart
 from spline import spline as splinepart
 from Brownian import Brownian as Brownianpart
+from periodic_exponential import periodic_exponential as periodic_exponentialpart
+from periodic_Matern32 import periodic_Matern32 as periodic_Matern32part
+from periodic_Matern52 import periodic_Matern52 as periodic_Matern52part
 
 #TODO these s=constructors are not as clean as we'd like. Tidy the code up
 #using meta-classes to make the objects construct properly wthout them.
@@ -196,3 +199,57 @@ def sympykern(D,k):
     A kernel from a symbolic sympy representation
     """
     return kern(D,[spkern(D,k)])
+
+def periodic_exponential(D=1,variance=1., lengthscale=None, period=2*np.pi,n_freq=10,lower=0.,upper=4*np.pi):
+    """
+    Construct an periodic exponential kernel
+
+    :param D: dimensionality, only defined for D=1
+    :type D: int
+    :param variance: the variance of the kernel
+    :type variance: float
+    :param lengthscale: the lengthscale of the kernel
+    :type lengthscale: float
+    :param period: the period
+    :type period: float
+    :param n_freq: the number of frequencies considered for the periodic subspace
+    :type n_freq: int
+    """
+    part = periodic_exponentialpart(D,variance, lengthscale, ARD)
+    return kern(D, [part])
+
+def periodic_Matern32(D,variance=1., lengthscale=None, period=2*np.pi,n_freq=10,lower=0.,upper=4*np.pi):
+    """
+     Construct a periodic Matern 3/2 kernel.
+
+     :param D: dimensionality, only defined for D=1
+     :type D: int
+     :param variance: the variance of the kernel
+     :type variance: float
+     :param lengthscale: the lengthscale of the kernel
+     :type lengthscale: float
+     :param period: the period
+     :type period: float
+     :param n_freq: the number of frequencies considered for the periodic subspace
+     :type n_freq: int
+    """
+    part = periodic_Matern32part(D,variance, lengthscale, ARD)
+    return kern(D, [part])
+
+def periodic_Matern52(D,variance=1., lengthscale=None, period=2*np.pi,n_freq=10,lower=0.,upper=4*np.pi):
+    """
+     Construct a periodic Matern 5/2 kernel.
+
+     :param D: dimensionality, only defined for D=1
+     :type D: int
+     :param variance: the variance of the kernel
+     :type variance: float
+     :param lengthscale: the lengthscale of the kernel
+     :type lengthscale: float
+     :param period: the period
+     :type period: float
+     :param n_freq: the number of frequencies considered for the periodic subspace
+     :type n_freq: int
+    """
+    part = periodic_Matern52part(D,variance, lengthscale, ARD)
+    return kern(D, [part])