diff --git a/examples/demo.py b/examples/demo.py
index 5d7bf0a..a5fa260 100644
--- a/examples/demo.py
+++ b/examples/demo.py
@@ -35,6 +35,8 @@ def demo_basic():
         print(i)
         optimizer.zero_grad()
         outputs = ddp_model(torch.randn(20, 10))
+        mat = torch.rand([3,3], dtype=torch.complex64)
+        inv_mat = torch.inverse(mat)
         labels = torch.randn(20, 5).to(device_id)
         loss_fn(outputs, labels).backward()
         optimizer.step()
diff --git a/examples/multi_gpu_simple_ptycho.py b/examples/multi_gpu_simple_ptycho.py
index ad7e646..94990f2 100644
--- a/examples/multi_gpu_simple_ptycho.py
+++ b/examples/multi_gpu_simple_ptycho.py
@@ -34,7 +34,7 @@ def demo():
     sampler = torchdata.distributed.DistributedSampler(dataset)
     # Make a dataloader
     #data_loader = torchdata.DataLoader(dataset, batch_size=20,
-    #                                   shuffle=True)
+    #                                   shuffle=True, num_workers=0)
     data_loader = torchdata.DataLoader(dataset, batch_size=20,
                                        shuffle=False, sampler=sampler)
     
@@ -42,26 +42,29 @@ def demo():
     dataset.get_as(device=device)
     
     # Define the optimizer
-    optimizer = MyAdam(model.parameters(), lr=0.01)
+    #optimizer = MyAdam(model.parameters(), lr=0.01)
+    optimizer = t.optim.Adam(model.parameters(), lr=0.01)
     
     normalization=0
-    for inputs, patterns in data_loader:
+    for inputs, patterns in dataset:#data_loader:
         normalization += t.sum(patterns)
         
     dist.all_reduce(normalization)
 
-    for it in range(100):
+    for it in range(10):
+        print(it)
         sampler.set_epoch(it)
         loss = 0
         N = 0
         t0 = time.time()
         for inputs, patterns in data_loader:
+            #print(inputs)
             N += 1
             def closure():
                 optimizer.zero_grad()
                 
                 sim_patterns = model.forward(*inputs)
-            
+                
                 if hasattr(model, 'mask'):
                     loss = model.loss(patterns,sim_patterns, mask=model.mask)
                 else:
@@ -70,12 +73,11 @@ def demo():
                 loss.backward()
                 return loss.detach()
 
-            loss += optimizer.step(closure).detach()#.cpu().numpy()
+            loss += optimizer.step(closure)#.cpu().numpy()
         #dist.all_reduce(loss)
         #loss = dist.all_reduce(loss)
         #print(it, 'time', time.time()-t0)
         #print(loss / normalization)
-        
     return loss#.cpu().numpy()
 
 if __name__=='__main__':
diff --git a/examples/simple_ptycho.py b/examples/simple_ptycho.py
index 2140f66..04f4218 100644
--- a/examples/simple_ptycho.py
+++ b/examples/simple_ptycho.py
@@ -18,7 +18,7 @@ model = cdtools.models.SimplePtycho.from_dataset(dataset)
 #    def __getattr__(self, name):
 #        return getattr(self.module, name)
 
-model = t.nn.DataParallel(model, device_ids=[0,1,2,3])
+#model = t.nn.DataParallel(model, device_ids=[0,1,2,3])
 
 
 # Make a dataloader
diff --git a/src/cdtools/models/simple_ptycho.py b/src/cdtools/models/simple_ptycho.py
index c4d85be..79c0df4 100644
--- a/src/cdtools/models/simple_ptycho.py
+++ b/src/cdtools/models/simple_ptycho.py
@@ -10,6 +10,11 @@ import numpy as np
 
 __all__ = ['SimplePtycho']
 
+class complexWrapper(t.Tensor):
+    def __new__(base_tensor):
+        return t.view_as_complex(base_tensor)
+        
+
 class SimplePtycho(CDIModel):
     """A simple ptychography model for exploring ideas and extensions
 
@@ -44,11 +49,14 @@ class SimplePtycho(CDIModel):
         # object
         self.register_buffer('probe_norm', t.max(t.abs(probe_guess)))
 
-        self.probe_data = t.nn.Parameter(t.view_as_real(probe_guess / self.probe_norm))
+        self.probe_data = complexParameter(probe_guess/self.probe_norm)
+        #self.probe_data = t.nn.Parameter(t.view_as_real(probe_guess / self.probe_norm))
         self.obj_data = t.nn.Parameter(t.view_as_real(obj_guess))
 
     @property
     def probe(self):
+        probe = t.view_as_complex(self.probe_data)
+        
         return t.view_as_complex(self.probe_data)
 
     @property
@@ -106,7 +114,6 @@ class SimplePtycho(CDIModel):
 
 
     def interaction(self, index, translations):
-
         pix_trans = tools.interactions.translations_to_pixel(self.probe_basis,
                                                              translations,
                                             surface_normal=self.surface_normal)
@@ -181,7 +188,7 @@ class SimplePtycho(CDIModel):
         ('Object Phase',
          lambda self, fig: p.plot_phase(self.obj, fig=fig, basis=self.probe_basis))
     ]
-
+    
 
     def ePIE(self, iterations, dataset, beta = 1.0):
         """Runs an ePIE reconstruction as described in `Maiden et al. (2017) <https://www.osapublishing.org/optica/abstract.cfm?uri=optica-4-7-736>`_.
diff --git a/src/cdtools/tools/interactions/interactions.py b/src/cdtools/tools/interactions/interactions.py
index 0b56d4f..a092bf3 100644
--- a/src/cdtools/tools/interactions/interactions.py
+++ b/src/cdtools/tools/interactions/interactions.py
@@ -43,7 +43,6 @@ def translations_to_pixel(basis, translations, surface_normal=t.Tensor([0.,0.,1.
     pixel_translations : torch.Tensor
         A Jx2 stack of translations in internal (i,j) pixel-space, or a single translation
     """
-
     projection_1 = t.as_tensor(np.array([[1,0,0],
                                          [0,1,0],
                                          [0,0,0]]),
@@ -53,7 +52,8 @@ def translations_to_pixel(basis, translations, surface_normal=t.Tensor([0.,0.,1.
     projection_2[2] = t.as_tensor(-surface_normal / surface_normal[2],
                                   dtype=projection_2.dtype,
                                   device=projection_2.device)
-    projection_2 = t.inverse(projection_2)
+    projection_2 = t.linalg.inv(projection_2)
+    
 
     basis_vectors_inv = t.pinverse(basis).to(device=translations.device,
                                              dtype=translations.dtype)