Continuous Convolution (#69)

* network handling update
* adding tutorial
* docs

pina/model/layers/integral.py

@@ -0,0 +1,63 @@
+import torch
+
+
+class Integral(object):
+
+    def __init__(self, param):
+        """Integral class for continous convolution
+
+        :param param: type of continuous convolution
+        :type param: string
+        """
+
+        if param == 'discrete':
+            self.make_integral = self.integral_param_disc
+        elif param == 'continuous':
+            self.make_integral = self.integral_param_cont
+        else:
+            raise TypeError
+
+    def __call__(self, *args, **kwds):
+        return self.make_integral(*args, **kwds)
+
+    def _prepend_zero(self, x):
+        """Create bins for performing integral
+
+        :param x: input tensor
+        :type x: torch.tensor
+        :return: bins for integrals
+        :rtype: torch.tensor
+        """
+        return torch.cat((torch.zeros(1, dtype=x.dtype, device=x.device), x))
+
+    def integral_param_disc(self, x, y, idx):
+        """Perform discretize integral
+            with discrete parameters
+
+        :param x: input vector
+        :type x: torch.tensor
+        :param y: input vector
+        :type y: torch.tensor
+        :param idx: indeces for different strides
+        :type idx: list
+        :return: integral
+        :rtype: torch.tensor
+        """
+        cs_idxes = self._prepend_zero(torch.cumsum(torch.tensor(idx), 0))
+        cs = self._prepend_zero(torch.cumsum(x.flatten() * y.flatten(), 0))
+        return cs[cs_idxes[1:]] - cs[cs_idxes[:-1]]
+
+    def integral_param_cont(self, x, y, idx):
+        """Perform discretize integral for continuous convolution
+            with continuous parameters
+
+        :param x: input vector
+        :type x: torch.tensor
+        :param y: input vector
+        :type y: torch.tensor
+        :param idx: indeces for different strides
+        :type idx: list
+        :return: integral
+        :rtype: torch.tensor
+        """
+        raise NotImplementedError