def shiftGaugeField(self, gaugeField, cpt, sign):
# Moving one site forwards is equivalent to shifting the whole field
# backwards, hence the minus sign (active/passive transform)
gaugeFieldShifted = tf.roll(gaugeField, -sign, cpt)
if cpt != 0:
return gaugeFieldShifted
# Apply reflecting BC's by setting links at the boundary to
# corresponding values from unshifted field
if sign == +1:
slicePos = self.latShape[cpt] - 2
else:
slicePos = 1
# For gathering from the shifted field (gathering from the variable is slow)
indices = FieldTools.sliceIndices(self.latShape, cpt, slicePos)
# For scattering onto the boundary
boundaryIndices = FieldTools.boundaryIndices(self.latShape, cpt, sign)
updates = tf.gather_nd(gaugeFieldShifted, indices)
boundaryUpdates = tf.gather_nd(gaugeField, boundaryIndices)
gaugeFieldShifted = tf.tensor_scatter_nd_update(
gaugeFieldShifted, boundaryIndices, updates)
if sign == -1:
# Set the r-links at the origin to the identity
rOriginIndices = tf.stack(
tf.meshgrid(0,
tf.range(self.latShape[1]),
tf.range(self.latShape[2]),
0,
indexing="ij"), -1)
rOriginUpdates = tf.eye(2,
batch_shape=tf.shape(rOriginIndices)[0:-1],
dtype=tf.complex128)
gaugeFieldShifted = tf.tensor_scatter_nd_update(
gaugeFieldShifted, rOriginIndices, rOriginUpdates)
return gaugeFieldShifted
def shiftScalarField(self, scalarField, cpt, sign):
# Moving one site forwards is equivalent to shifting the whole field
# backwards, hence the minus sign (active/passive transform)
scalarFieldShifted = tf.roll(scalarField, -sign, cpt)
if cpt != 0:
return scalarFieldShifted
# Apply reflecting BC's by setting links at the boundary to
# corresponding values from unshifted field
if sign == +1:
slicePos = self.latShape[cpt] - 2
else:
slicePos = 1
# For gathering from the shifted field (gathering from the variable is slow)
indices = FieldTools.sliceIndices(self.latShape, cpt, slicePos)
# For scattering onto the boundary
boundaryIndices = FieldTools.boundaryIndices(self.latShape, cpt, sign)
updates = tf.gather_nd(scalarFieldShifted, indices)
scalarFieldShifted = tf.tensor_scatter_nd_update(
scalarFieldShifted, boundaryIndices, updates)
return scalarFieldShifted