diff --git a/examples/00-basic/10-math_operations.py b/examples/00-basic/10-math_operations.py new file mode 100644 index 0000000000..81d355d6e3 --- /dev/null +++ b/examples/00-basic/10-math_operations.py @@ -0,0 +1,150 @@ +# noqa: D400 +""" +.. _ref_math_operators_example: + +Mathematical Operations +~~~~~~~~~~~~~~~~~~~~~~~ + +DPF provides operators for implementing mathematical operations, +ranging from addition and multiplication to FFT and QR solving. + +For a complete list, see :ref:`ref_dpf_operators_reference`, under the math section. + +""" + +# Import the necessary modules +import ansys.dpf.core as dpf + +############################################################################### +# Addition +# ~~~~~~~~ + +# Initialize Fields +num_entities = 2 +field1 = dpf.Field(nentities=2) +field2 = dpf.Field(nentities=2) + +# By default, Fields contain 3d vectors. +# So with three entities we need nine values. +field1.data = [1.0, 2.0, 3.0, 4.0, 5.0, 6.0] +field2.data = [1.0, 2.0, 3.0, 4.0, 5.0, 6.0] + +field1.scoping.ids = range(num_entities) +field2.scoping.ids = range(num_entities) +############################################################################### +# Once the fields are ready, we can instantiate an operator. +add_op = dpf.operators.math.add(field1, field2) + +############################################################################### +# Finally, we use eval() to compute and retrieve the result. +field3 = add_op.eval() + +# = [[2. 4. 6.] [8. 10. 12.]] +print(field3.data) + +############################################################################### +# Dot product +# ~~~~~~~~~~~ +dot_op = dpf.operators.math.generalized_inner_product(field1, field2) + +# (1. * 1.) + (2. * 2.) + (3. * 3.) = 14. +# (4. * 4.) + (5. * 5.) + (6. * 6.) = 77. +field3 = dot_op.eval() +print(field3.data) + + +############################################################################### +# Power +# ~~~~~ +field = dpf.Field(nentities=1) +field1.data = [1.0, 2.0, 3.0] +field1.scoping.ids = [1] + +pow_op = dpf.operators.math.pow(field1, 3.0) + +# [1. 8. 27.] +field3 = pow_op.eval() +print(field3.data) + + +############################################################################### +# L2 norm +# ~~~~~~~ +field1.data = [16.0, -8.0, 2.0] +norm_op = dpf.operators.math.norm(field1) + +# [ 18. ] +field3 = norm_op.eval() +print(field3.data) + + +############################################################################### +# Accumulate +# ~~~~~~~~~~ +# First we define fields. By default, fields represent 3D vectors +# so one elementary data is a 3D vector. +# The optional ponderation field is a field which takes one value per entity, +# so we need to change its dimensionality (1D). +num_entities = 3 +input_field = dpf.Field(nentities=num_entities) +ponderation_field = dpf.Field(num_entities) +ponderation_field.dimensionality = dpf.Dimensionality([1]) + +input_field.scoping.ids = range(num_entities) +ponderation_field.scoping.ids = range(num_entities) + +############################################################################### +# Fill fields with data. +# Add nine values because there are three entities. +input_field.data = [-2.0, 2.0, 4.0, -5.0, 0.5, 1.0, 7.0, 3.0, -3.0] +############################################################################### +# Three weights, one per entity. +ponderation_field.data = [0.5, 2.0, 0.5] + +############################################################################### +# Retrieve the result. +acc = dpf.operators.math.accumulate(fieldA=input_field, ponderation=ponderation_field) +output_field = acc.outputs.field() + +# (-2.0 * 0.5) + (-5.0 * 2.0) + (7.0 * 0.5) = -7.5 +# (2.0 * 0.5) + (0.5 * 2.0) + (3.0 * 0.5) = 3.5 +# (4.0 * 0.5) + (1.0 * 2.0) + (-3.0 * 0.5) = 2.5 +print(output_field.data) + +############################################################################### +# With scoping +# ~~~~~~~~~~~~ +field1.data = [1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0] +field2.data = [1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0] + +############################################################################### +# Next, we need to provide information about the scoping. +# DPF needs to know the IDs of the data we just provided, +# so that it can apply an operator on a subset of the original data. +# +# By providing these integers we only select the data with an ID in common. +# Here we are selecting the third elementary data of the first field, +# and the first elementary data of the second field, +# Other elementary data is not taken into account when using an operator that needs two operands. +field1.scoping.ids = [1, 2, 3] +field2.scoping.ids = [3, 4, 5] + +add_op = dpf.operators.math.add(field1, field2) +field3 = add_op.eval() + +# Only the third entity was changed +# because it is the only operator where two operands were provided. +print(field3.data) +# [[8. 10. 12.]] +print(field3.get_entity_data_by_id(3)) + +############################################################################### +# Dot product + +dot_op = dpf.operators.math.generalized_inner_product(field1, field2) + +# We obtain zeros for IDs where there could not be two operands. +# (7. * 1.) + (8. * 2.) + (9. * 3.) = 50. +# [0. 0. 50. 0. 0.] +field3 = dot_op.eval() +print(field3.data)