fix pad 0 size (#3277)

* fix pad 0 size

* put in view, not pad

* test was wrong

test/imported/test_indexing.py

@@ -996,7 +996,8 @@ class TestIndexing(unittest.TestCase):
     z = y[:, 1:1, :]
     numpy_testing_assert_equal_helper((2, 0, 4), z.shape)
     # this isn't technically necessary, but matches NumPy stride calculations.
-    numpy_testing_assert_equal_helper((60, 20, 5), z.lazydata.st.real_strides())
+    # NOTE: this is empty and shouldn't have strides
+    #numpy_testing_assert_equal_helper((60, 20, 5), z.lazydata.st.real_strides())
     # NOTE tinygrad's int slicing implementation makes this not contiguous
     # self.assertTrue(z.lazydata.st.contiguous)
 

test/test_lazybuffer.py

@@ -2,7 +2,6 @@
 import numpy as np
 import unittest
 from tinygrad import Tensor, Device, dtypes
-from tinygrad.device import Interpreted
 
 class TestLazyBuffer(unittest.TestCase):
   def test_fromcpu_shape_tracker(self):
@@ -56,18 +55,7 @@ class TestLazyBuffer(unittest.TestCase):
     a = Tensor.zeros(4,4,4).shrink((None, (0,0), None)).cast(dtypes.int32)
     b = Tensor.zeros(4,1,4)
     c = a.cat(b, dim=1)
-
-    if isinstance(Device[Device.DEFAULT], Interpreted):
-      # TODO: fix cast resets shapetracker and remove this block
-      # this is expectedFailure with a condition
-      try:
-        np.testing.assert_allclose(c.numpy(), np.concatenate((a.numpy(), b.numpy()), axis=1))
-      except Exception:
-        pass
-      else:
-        raise ValueError("assert_allclose not failed")
-    else:
-      np.testing.assert_allclose(c.numpy(), np.concatenate((a.numpy(), b.numpy()), axis=1))
+    np.testing.assert_allclose(c.numpy(), np.concatenate((a.numpy(), b.numpy()), axis=1))
 
 if __name__ == "__main__":
   unittest.main()

tinygrad/lazy.py

@@ -138,6 +138,7 @@ class LazyBuffer:
   # *** movement ops ***
 
   def _view(self, new_st:ShapeTracker) -> LazyBuffer:
+    if self.st.size == 0: return self.const(0, new_st.shape)
     if new_st.contiguous and self.base.shape == new_st.shape: return self.base
     return create_lazybuffer(self.device, new_st, self.dtype, base=self.base)