Add dcshift to functional

[bhargavkathivarapu]

Hi ,
Regarding the issue #260 ( Reducing dependency in Sox)
Implemented dcshift function in functional.py

• function.rst - updated with new fucntion
• test_sox_compatibility.py - Added two tests for dcshift and changes as per Small clean up test_sox_compatibility.py #557 . Tests passed

..................gain: can't reclaim headroom
.
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Ran 19 tests in 475.924s

OK

• test_batch_consistency.py - added test for dcshift

.................
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Ran 17 tests in 204.327s

OK

• test_torchscript_consistency.py - added test but giving error, couldn't understand the issue.
  Below is the log

$ python test/test_torchscript_consistency.py 
.............E...................sssssssssssssssssssssssssssssssss...............sssssssssssssss
======================================================================
ERROR: test_dcshift (__main__.TestFunctionalCPU)
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Traceback (most recent call last):
  File "test/test_torchscript_consistency.py", line 428, in test_dcshift
    self._assert_consistency(func, waveform)
  File "test/test_torchscript_consistency.py", line 38, in _assert_consistency
    return _assert_functional_consistency(func, tensor, self.device, shape_only=shape_only)
  File "test/test_torchscript_consistency.py", line 14, in _assert_functional_consistency
    ts_func = torch.jit.script(func)
  File "/Users/bhargav/pytorch/torch/jit/__init__.py", line 1296, in script
    fn = torch._C._jit_script_compile(qualified_name, ast, _rcb, get_default_args(obj))
  File "/Users/bhargav/pytorch/torch/jit/_recursive.py", line 559, in try_compile_fn
    return torch.jit.script(fn, _rcb=rcb)
  File "/Users/bhargav/pytorch/torch/jit/__init__.py", line 1293, in script
    ast = get_jit_def(obj)
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 173, in get_jit_def
    return build_def(ctx, py_ast.body[0], type_line, self_name)
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 206, in build_def
    build_stmts(ctx, body))
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 129, in build_stmts
    stmts = [build_stmt(ctx, s) for s in stmts]
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 129, in <listcomp>
    stmts = [build_stmt(ctx, s) for s in stmts]
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 181, in __call__
    return method(ctx, node)
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 361, in build_If
    build_stmts(ctx, stmt.body),
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 129, in build_stmts
    stmts = [build_stmt(ctx, s) for s in stmts]
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 129, in <listcomp>
    stmts = [build_stmt(ctx, s) for s in stmts]
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 181, in __call__
    return method(ctx, node)
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 288, in build_Assign
    rhs = build_expr(ctx, stmt.value)
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 181, in __call__
    return method(ctx, node)
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 457, in build_Call
    kw_expr = build_expr(ctx, kw.value)
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 181, in __call__
    return method(ctx, node)
  File "/Users/bhargav/pytorch/torch/jit/frontend.py", line 517, in build_UnaryOp
    r = ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + len(op_token))
TypeError: object of type 'NoneType' has no len()

@vincentqb could you please review these changes

[mthrok]

Can you also add dcshift to __all__ in functional.py?

[mthrok]

Looks good to me 🙂