def testGradientMult(self):
with self.session(use_gpu=False, graph=tf.Graph()):
p = self._testParams()
mdl = p.Instantiate()
mdl.FPropDefaultTheta()
var_grads = py_utils.ComputeGradients(mdl.loss, mdl.vars)
py_utils.ApplyGradMultiplier(var_grads, -1.1)
def ScaleGradients(self, var_grads):
"""Scales gradients according to training params.
Args:
var_grads: a `.NestedMap` whose values are (var, grad) pairs.
Returns:
(has_nan_or_inf, grad_scale, final_var_grads).
- has_nan_or_inf: a scalar of 0 or 1, indicating whether there is any NaN
or Inf in input gradients.
- grad_scale: the gradient scale. 0 if gradient updates should be skipped
for the step.
- final_var_grads: a `.NestedMap` whose values are (var, grad) pairs, where
gradients have already been scaled.
"""
p = self.params
tp = p.train
# Computes gradients' norm and adds their summaries. Note that all_grad_norm
# may be nan, which may cause grad_scale to be nan.
for name, vg in var_grads.FlattenItems():
summary_utils.AddNormSummary(p, name, py_utils.NestedMap(s=vg))
_, all_grad_norm = summary_utils.AddNormSummary(p, 'all', var_grads)
grad_norm_is_nan_or_inf = tf.logical_or(tf.is_nan(all_grad_norm),
tf.is_inf(all_grad_norm))
# Optional gradient adjustment. Note that this happens after computing
# all_grad_norm.
var_grads = self.AdjustGradients(var_grads)
# Handles NaN/Inf gradients.
has_nan_or_inf = self._HasNanOrInf(var_grads)
# Grad norm can still be inf even if none of the individual grad is inf.
has_nan_or_inf = tf.logical_or(has_nan_or_inf, grad_norm_is_nan_or_inf)
# Computes gradient's scale.
grad_scale = tf.constant(1.0)
if tp.clip_gradient_norm_to_value:
# If all_grad_norm > tp.clip_gradient_norm_to_value, scales
# all_grads so that the norm is 1.0.
grad_scale = tf.minimum(
1.0, tp.clip_gradient_norm_to_value / all_grad_norm)
if tp.grad_norm_to_clip_to_zero:
# If all_grad_norm > tp.grad_norm_to_clip_to_zero, treats
# grad_scale as 0. This way, we ignore this step.
grad_scale *= tf.cast(all_grad_norm < tp.grad_norm_to_clip_to_zero,
p.dtype)
if tp.grad_norm_tracker:
grad_scale *= self.grad_norm_tracker.FPropDefaultTheta(
all_grad_norm, has_nan_or_inf)
# Force grad_scale to be 0 if there is any NaN or Inf in gradients.
grad_scale = tf.where(has_nan_or_inf, 0.0, grad_scale)
summary_utils.scalar(p, 'grad_scale_all', grad_scale)
final_var_grads = py_utils.ApplyGradMultiplier(var_grads, grad_scale)
return has_nan_or_inf, grad_scale, final_var_grads
def _ApplyAndReset():
with tf.control_dependencies([
self._opt.Apply(
lr, py_utils.ApplyGradMultiplier(var_grad, 1. / p.accum_steps))
]):
return tf.group(
*[tf.assign(a, tf.zeros_like(a)) for _, a in var_grad.Flatten()])
def _Apply1(proj_layer, opt):
output1 = proj_layer.FPropDefaultTheta(inputs1, in_padding1)
output2 = proj_layer.FPropDefaultTheta(inputs2, in_padding2)
loss1 = tf.reduce_sum(output1)
loss2 = tf.reduce_sum(output2)
var_grads1 = py_utils.ComputeGradients(loss1, proj_layer.vars)
var_grads2 = py_utils.ComputeGradients(loss2, proj_layer.vars)
_ = opt.Apply(lr, py_utils.ApplyGradMultiplier(var_grads1, 1. / 2.))
_ = opt.Apply(lr, py_utils.ApplyGradMultiplier(var_grads2, 1. / 2.))
vars1_1 = proj_layer.vars.Flatten()
grads1_1 = var_grads1.Transform(tuple)
grads1_2 = var_grads2.Transform(tuple)
return vars1_1, grads1_1, grads1_2
def testAccumulator(self):
# testAccumulator compares
# - explicit averaging of independently computed var_grads1 and
# var_grads2,
# - Accumulator(SGD) optimizer effectively doing this over 2 steps.
np.random.seed(12345)
np_input1 = np.random.normal(0.1, 0.5, [2, 4, 3])
np.random.seed(12346)
np_input2 = np.random.normal(0.1, 0.5, [2, 4, 3])
with self.session(use_gpu=True, graph=tf.Graph()) as sess:
tf.random.set_seed(123456)
params = layers.ProjectionLayer.Params()
params.name = 'proj'
params.dtype = tf.float64
params.input_dim = 3
params.output_dim = 2
params.params_init = py_utils.WeightInit.Gaussian(0.01, 123456)
params.batch_norm = False
proj_layer = layers.ProjectionLayer(params)
inputs1 = tf.placeholder(shape=[2, 4, 3], dtype=tf.float64)
in_padding1 = tf.zeros([2, 4, 1], dtype=tf.float64)
inputs2 = tf.placeholder(shape=[2, 4, 3], dtype=tf.float64)
in_padding2 = tf.zeros([2, 4, 1], dtype=tf.float64)
output1 = proj_layer.FPropDefaultTheta(inputs1, in_padding1)
output2 = proj_layer.FPropDefaultTheta(inputs2, in_padding2)
loss1 = tf.reduce_sum(output1)
loss2 = tf.reduce_sum(output2)
var_grads1 = py_utils.ComputeGradients(loss1, proj_layer.vars)
var_grads2 = py_utils.ComputeGradients(loss2, proj_layer.vars)
op = optimizer.SGD.Params()
opt = op.Instantiate()
lr = 1e-1
with tf.control_dependencies([loss1, loss2]):
var_update_op1 = opt.Apply(
lr, py_utils.ApplyGradMultiplier(var_grads1, 1. / 2.))
with tf.control_dependencies([var_update_op1]):
var_update_op2 = opt.Apply(
lr, py_utils.ApplyGradMultiplier(var_grads2, 1. / 2.))
self.evaluate(tf.global_variables_initializer())
vars1 = self.evaluate(proj_layer.vars.Flatten())
loss1_1, grads1_1, loss1_2, grads1_2 = sess.run(
[
loss1,
var_grads1.Transform(tuple), loss2,
var_grads2.Transform(tuple)
],
feed_dict={
inputs1: np_input1,
inputs2: np_input2,
},
)
sess.run([var_update_op2],
feed_dict={
inputs1: np_input1,
inputs2: np_input2,
})
vars1_1 = self.evaluate(proj_layer.vars.Flatten())
with self.session(use_gpu=True, graph=tf.Graph()) as sess:
tf.random.set_seed(123456)
params = layers.ProjectionLayer.Params()
params.name = 'proj'
params.dtype = tf.float64
params.input_dim = 3
params.output_dim = 2
params.params_init = py_utils.WeightInit.Gaussian(0.01, 123456)
params.batch_norm = False
proj_layer = layers.ProjectionLayer(params)
in_padding1 = tf.zeros([2, 4, 1], dtype=tf.float64)
inputs1 = tf.placeholder(shape=[2, 4, 3], dtype=tf.float64)
output1 = proj_layer.FPropDefaultTheta(inputs1, in_padding1)
loss = tf.reduce_sum(output1)
var_grads = py_utils.ComputeGradients(loss, proj_layer.vars)
op = optimizer.Accumulator.Params().Set(
accum_steps=2,
dtype=tf.float64,
optimizer_tpl=optimizer.SGD.Params())
opt = op.Instantiate()
lr = 1e-1
with cluster_factory.ForTestingWorker(add_summary=True):
var_update_op = opt.Apply(lr, var_grads)
increment_global_step_op = tf.assign_add(
py_utils.GetOrCreateGlobalStepVar(), 1)
self.evaluate(tf.global_variables_initializer())
vars2 = self.evaluate(proj_layer.vars.Flatten())
loss2_1, grads2_1 = sess.run(
[loss, var_grads.Transform(tuple)],
feed_dict={
inputs1: np_input1,
})
loss2_2, grads2_2 = sess.run(
[loss, var_grads.Transform(tuple)],
feed_dict={
inputs1: np_input2,
})
acc_0 = self.evaluate([
v for v in tf.global_variables()
if 'grad_accumulator' in v.name
])[0]
sess.run([var_update_op], feed_dict={
inputs1: np_input1,
})
acc_1 = self.evaluate([
v for v in tf.global_variables()
if 'grad_accumulator' in v.name
])[0]
vars2_intermediate = self.evaluate(proj_layer.vars.Flatten())
self.evaluate(increment_global_step_op)
sess.run([var_update_op], feed_dict={
inputs1: np_input2,
})
acc_2 = self.evaluate([
v for v in tf.global_variables()
if 'grad_accumulator' in v.name
])[0]
vars2_1 = self.evaluate(proj_layer.vars.Flatten())
summary = tf.Summary.FromString(
self.evaluate(tf.summary.merge_all()))
tf.logging.info(f'summary: {summary}')
self.assertEqual(summary.value[0].tag, 'sgd_lr')
self.assertAllClose(vars1, vars2)
self.assertAllClose(acc_0, np.zeros_like(acc_0))
self.assertAllClose(acc_1, grads2_1['w'][1])
self.assertAllClose(acc_2, np.zeros_like(acc_0))
self.assertAllClose(loss1_1, loss2_1)
self.assertAllClose(loss1_2, loss2_2)
self.assertAllClose(grads1_1, grads2_1)
self.assertAllClose(grads1_2, grads2_2)
self.assertAllClose(vars1, vars2_intermediate)
self.assertAllClose(vars2[0], grads2_1['w'][0])
self.assertAllClose(vars2[0], grads2_2['w'][0])
self.assertAllClose(
vars1[0] - 0.5 * lr * (grads1_1['w'][1] + grads1_2['w'][1]),
vars1_1[0])
self.assertAllClose(
vars2[0] - 0.5 * lr * (grads2_1['w'][1] + grads2_2['w'][1]),
vars2_1[0])
self.assertAllClose(vars2, vars2_intermediate)
self.assertAllClose(vars1_1, vars2_1)
def ScaleGradients(self, var_grads, gradient_adjuster=None):
"""Scales gradients according to training params.
Args:
var_grads: a `.NestedMap` whose values are (var, grad) pairs.
gradient_adjuster: if not None, a function that mutates a given var_grads.
Returns:
A `.NestedMap` containing:
- has_nan_or_inf: a scalar of 0 or 1, indicating whether there is any NaN
or Inf in input gradients.
- final_var_grads: a `.NestedMap` whose values are (var, grad) pairs,
where gradients have already been scaled.
- grad_scale: the gradient scale. 0 if gradient updates should be skipped
for the step. (Optional, only returned in case global norm clipping is
used.)
"""
p = self.params
# Computes gradients' norm and adds their summaries. Note that all_grad_norm
# may be nan, which may cause grad_scale to be nan.
for name, vg in var_grads.FlattenItems():
summary_utils.AddNormSummary(name + '/' + p.name,
py_utils.NestedMap(s=vg))
all_grad_norm = tf.sqrt(
py_utils.SumSquared([
g for (_, g) in py_utils.NestedMap(child=var_grads).Flatten()
]))
all_var_norm = tf.sqrt(
py_utils.SumSquared([
v for (v, _) in py_utils.NestedMap(child=var_grads).Flatten()
]))
grad_norm_is_nan_or_inf = tf.logical_or(tf.is_nan(all_grad_norm),
tf.is_inf(all_grad_norm))
# Optional gradient adjustment. Note that this happens after computing
# all_grad_norm.
if gradient_adjuster is not None:
tf.logging.info('gradient_adjuster=%s', gradient_adjuster)
var_grads = gradient_adjuster(var_grads)
# Handles NaN/Inf gradients.
has_nan_or_inf = py_utils.HasNanOrInfGradient(var_grads)
# Grad norm can still be inf even if none of the individual grad is inf.
has_nan_or_inf = tf.logical_or(has_nan_or_inf, grad_norm_is_nan_or_inf)
return_values = py_utils.NestedMap()
if p.clip_gradient_single_norm_to_value:
# Currently using both types of clipping simultaneously is unsupported.
if p.clip_gradient_norm_to_value:
raise ValueError(
'Cannot use clip_gradient_single_norm_to_value=%f and '
'clip_gradient_norm_to_value=%f.' %
(p.clip_gradient_single_norm_to_value,
p.clip_gradient_norm_to_value))
final_var_grads = py_utils.ApplyGradNormCliping(
var_grads, p.clip_gradient_single_norm_to_value)
else:
grad_scale = self._GetGlobalGradScale(all_grad_norm,
has_nan_or_inf)
self._AddEvalMetric('grad_norm/all', all_grad_norm,
tf.constant(1.0))
self._AddEvalMetric('var_norm/all', all_var_norm, tf.constant(1.0))
self._AddEvalMetric('grad_scale_all', grad_scale, tf.constant(1.0))
final_var_grads = py_utils.ApplyGradMultiplier(
var_grads, grad_scale)
return_values.grad_scale = grad_scale
return_values.has_nan_or_inf = has_nan_or_inf
return_values.final_var_grads = final_var_grads
return return_values
def testAccumulator(self):
# testAccumulator compares
# - explicit averaging of independently computed var_grads1 and
# var_grads2,
# - Accumulator(SGD) optimizer effectively doing this over 2 steps.
np.random.seed(12345)
np_input1 = np.random.normal(0.1, 0.5, [2, 4, 3])
np.random.seed(12346)
np_input2 = np.random.normal(0.1, 0.5, [2, 4, 3])
g1 = tf.Graph()
with g1.as_default():
tf.set_random_seed(123456)
params = layers.ProjectionLayer.Params()
params.name = 'proj'
params.dtype = tf.float64
params.input_dim = 3
params.output_dim = 2
params.params_init = py_utils.WeightInit.Gaussian(0.01, 123456)
params.is_eval = False
params.batch_norm = False
proj_layer = layers.ProjectionLayer(params)
inputs1 = tf.placeholder(shape=[2, 4, 3], dtype=tf.float64)
in_padding1 = tf.zeros([2, 4, 1], dtype=tf.float64)
inputs2 = tf.placeholder(shape=[2, 4, 3], dtype=tf.float64)
in_padding2 = tf.zeros([2, 4, 1], dtype=tf.float64)
output1 = proj_layer.FPropDefaultTheta(inputs1, in_padding1)
output2 = proj_layer.FPropDefaultTheta(inputs2, in_padding2)
loss1 = tf.reduce_sum(output1)
loss2 = tf.reduce_sum(output2)
var_grads1 = py_utils.ComputeGradients(loss1, proj_layer.vars)
var_grads2 = py_utils.ComputeGradients(loss2, proj_layer.vars)
op = optimizer.SGD.Params().Set(add_summary=False)
opt = op.cls(op)
lr = 1e-1
with tf.control_dependencies([loss1, loss2]):
var_update_op1 = opt.Apply(
lr, py_utils.ApplyGradMultiplier(var_grads1, 1. / 2.))
with tf.control_dependencies([var_update_op1]):
var_update_op2 = opt.Apply(
lr, py_utils.ApplyGradMultiplier(var_grads2, 1. / 2.))
init_op = tf.global_variables_initializer()
with self.session(use_gpu=True, graph=g1) as sess:
sess.run(init_op)
vars1 = sess.run(proj_layer.vars.Flatten())
loss1_1, grads1_1, loss1_2, grads1_2 = sess.run(
[loss1, var_grads1, loss2, var_grads2],
feed_dict={
inputs1: np_input1,
inputs2: np_input2,
})
sess.run(
[var_update_op2], feed_dict={
inputs1: np_input1,
inputs2: np_input2,
})
vars1_1 = sess.run(proj_layer.vars.Flatten())
g2 = tf.Graph()
with g2.as_default():
tf.set_random_seed(123456)
params = layers.ProjectionLayer.Params()
params.name = 'proj'
params.dtype = tf.float64
params.input_dim = 3
params.output_dim = 2
params.params_init = py_utils.WeightInit.Gaussian(0.01, 123456)
params.is_eval = False
params.batch_norm = False
proj_layer = layers.ProjectionLayer(params)
in_padding1 = tf.zeros([2, 4, 1], dtype=tf.float64)
inputs1 = tf.placeholder(shape=[2, 4, 3], dtype=tf.float64)
output1 = proj_layer.FPropDefaultTheta(inputs1, in_padding1)
loss = tf.reduce_sum(output1)
var_grads = py_utils.ComputeGradients(loss, proj_layer.vars)
op = optimizer.Accumulator.Params().Set(
accum_steps=2,
dtype=tf.float64,
optimizer_tpl=optimizer.SGD.Params().Set(add_summary=False))
opt = op.cls(op)
lr = 1e-1
var_update_op = opt.Apply(lr, var_grads)
init_op = tf.global_variables_initializer()
global_step = py_utils.GetOrCreateGlobalStep()
increment_global_step_op = tf.assign_add(global_step, 1)
with self.session(use_gpu=True, graph=g2) as sess:
sess.run(init_op)
vars2, global_step = sess.run([proj_layer.vars.Flatten(), global_step])
loss2_1, grads2_1 = sess.run(
[loss, var_grads], feed_dict={
inputs1: np_input1,
})
loss2_2, grads2_2 = sess.run(
[loss, var_grads], feed_dict={
inputs1: np_input2,
})
acc_0 = sess.run(
[v for v in tf.global_variables() if 'grad_accumulator' in v.name])[0]
sess.run(
[var_update_op], feed_dict={
inputs1: np_input1,
})
acc_1 = sess.run(
[v for v in tf.global_variables() if 'grad_accumulator' in v.name])[0]
vars2_intermediate = sess.run(proj_layer.vars.Flatten())
sess.run(increment_global_step_op)
sess.run(
[var_update_op], feed_dict={
inputs1: np_input2,
})
acc_2 = sess.run(
[v for v in tf.global_variables() if 'grad_accumulator' in v.name])[0]
vars2_1 = sess.run(proj_layer.vars.Flatten())
self.assertAllClose(vars1, vars2)
self.assertAllClose(acc_0, np.zeros_like(acc_0))
self.assertAllClose(acc_1, grads2_1['w'][1])
self.assertAllClose(acc_2, np.zeros_like(acc_0))
self.assertAllClose(loss1_1, loss2_1)
self.assertAllClose(loss1_2, loss2_2)
self.assertAllClose(grads1_1, grads2_1)
self.assertAllClose(grads1_2, grads2_2)
self.assertAllClose(vars1, vars2_intermediate)
self.assertAllClose(vars2[0], grads2_1['w'][0])
self.assertAllClose(vars2[0], grads2_2['w'][0])
self.assertAllClose(
vars1[0] - 0.5 * lr * (grads1_1['w'][1] + grads1_2['w'][1]), vars1_1[0])
self.assertAllClose(
vars2[0] - 0.5 * lr * (grads2_1['w'][1] + grads2_2['w'][1]), vars2_1[0])
self.assertAllClose(vars2, vars2_intermediate)
self.assertAllClose(vars1_1, vars2_1)
