def _test_if(x):
y = ops.Const(1)
with ops.If(ops.GT([x, ops.Const(50)])):
ops.Const(2, blob_out=y)
with ops.If(ops.LT([x, ops.Const(50)])):
ops.Const(3, blob_out=y)
ops.stop()
ops.Const(4, blob_out=y)
return y
def test_if_net(self):
with NetBuilder() as nb:
x0 = ops.Const(0)
x1 = ops.Const(1)
x2 = ops.Const(2)
y0 = ops.Const(0)
y1 = ops.Const(1)
y2 = ops.Const(2)
# basic logic
first_res = ops.Const(0)
with ops.IfNet(ops.Const(True)):
ops.Const(1, blob_out=first_res)
with ops.Else():
ops.Const(2, blob_out=first_res)
second_res = ops.Const(0)
with ops.IfNet(ops.Const(False)):
ops.Const(1, blob_out=second_res)
with ops.Else():
ops.Const(2, blob_out=second_res)
# nested and sequential ifs,
# empty then/else,
# passing outer blobs into branches,
# writing into outer blobs, incl. into input blob
# using local blobs
with ops.IfNet(ops.LT([x0, x1])):
local_blob = ops.Const(900)
ops.Add([ops.Const(100), local_blob], [y0])
gt = ops.GT([x1, x2])
with ops.IfNet(gt):
# empty then
pass
with ops.Else():
ops.Add([y1, local_blob], [local_blob])
ops.Add([ops.Const(100), y1], [y1])
with ops.IfNet(ops.EQ([local_blob, ops.Const(901)])):
ops.Const(7, blob_out=y2)
ops.Add([y1, y2], [y2])
with ops.Else():
# empty else
pass
plan = Plan('if_net_test')
plan.AddStep(to_execution_step(nb))
ws = workspace.C.Workspace()
ws.run(plan)
first_res_value = ws.blobs[str(first_res)].fetch()
second_res_value = ws.blobs[str(second_res)].fetch()
y0_value = ws.blobs[str(y0)].fetch()
y1_value = ws.blobs[str(y1)].fetch()
y2_value = ws.blobs[str(y2)].fetch()
self.assertEquals(first_res_value, 1)
self.assertEquals(second_res_value, 2)
self.assertEquals(y0_value, 1000)
self.assertEquals(y1_value, 101)
self.assertEquals(y2_value, 108)
self.assertTrue(str(local_blob) not in ws.blobs)
# In the first example, we first define several blobs and then use 'If' operator to set value of one of them conditionally depending on values of other blobs.
# In[1]:
from caffe2.python import workspace
from caffe2.python.core import Plan, to_execution_step, Net
from caffe2.python.net_builder import ops, NetBuilder
# In[2]:
with NetBuilder() as nb:
ops.Const(0.0, blob_out="zero")
ops.Const(1.0, blob_out="one")
ops.Const(0.5, blob_out="x")
ops.Const(0.0, blob_out="y")
with ops.IfNet(ops.GT(["x", "zero"])):
ops.Copy("one", "y")
with ops.Else():
ops.Copy("zero", "y")
# Note the usage of NetBuilder's ops.IfNet and ops.Else calls: ops.IfNet accepts a blob reference or blob name as an input, it expects an input blob to have a scalar value convertible to bool, also note that optional ops.Else is at the same level as ops.IfNet and immediately follows corresponding ops.IfNet. Let's execute resulting net (execution step) and check values of blobs.
# In[3]:
plan = Plan('if_net_test')
plan.AddStep(to_execution_step(nb))
ws = workspace.C.Workspace()
ws.run(plan)
print('x = ', ws.blobs["x"].fetch())
print('y = ', ws.blobs["y"].fetch())