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Merge pull request #17370 from mitodl/pdpinch/tensor-variables

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Allow primes and tensor notation in variable names
This commit is contained in:
Ned Batchelder
2018-03-05 15:32:48 -05:00
committed by GitHub
parent 1ee7966df7 54b85ddd13
commit 6bbb68ee1c
2 changed files with 16 additions and 5 deletions
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17
common/lib/calc/calc/calc.py
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@@ -381,10 +381,19 @@ class ParseAugmenter(object):
# Predefine recursive variables.
expr = Forward()
# Handle variables passed in. They must start with letters/underscores
# and may contain numbers afterward.
inner_varname = Word(alphas + "_", alphanums + "_")
varname = Group(inner_varname)("variable")
# Handle variables passed in. They must start with a letter
# and may contain numbers and underscores afterward.
inner_varname = Combine(Word(alphas, alphanums + "_") + ZeroOrMore("'"))
# Alternative variable name in tensor format
# Tensor name must start with a letter, continue with alphanums
# Indices may be alphanumeric
# e.g., U_{ijk}^{123}
upper_indices = Literal("^{") + Word(alphanums) + Literal("}")
lower_indices = Literal("_{") + Word(alphanums) + Literal("}")
tensor_lower = Combine(Word(alphas, alphanums) + lower_indices + ZeroOrMore("'"))
tensor_mixed = Combine(Word(alphas, alphanums) + Optional(lower_indices) + upper_indices + ZeroOrMore("'"))
# Test for mixed tensor first, then lower tensor alone, then generic variable name
varname = Group(tensor_mixed | tensor_lower | inner_varname)("variable")
varname.setParseAction(self.variable_parse_action)
# Same thing for functions.

4
common/lib/calc/calc/tests/test_calc.py
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@@ -440,7 +440,7 @@ class EvaluatorTest(unittest.TestCase):
"""
Substitution of variables into simple equations
"""
variables = {'x': 9.72, 'y': 7.91, 'loooooong': 6.4}
variables = {'x': 9.72, 'y': 7.91, 'loooooong': 6.4, "f_0'": 2.0, "T_{ijk}^{123}''": 5.2}
# Should not change value of constant
# even with different numbers of variables...
@@ -452,6 +452,8 @@ class EvaluatorTest(unittest.TestCase):
self.assertEqual(calc.evaluator(variables, {}, 'x'), 9.72)
self.assertEqual(calc.evaluator(variables, {}, 'y'), 7.91)
self.assertEqual(calc.evaluator(variables, {}, 'loooooong'), 6.4)
self.assertEqual(calc.evaluator(variables, {}, "f_0'"), 2.0)
self.assertEqual(calc.evaluator(variables, {}, "T_{ijk}^{123}''"), 5.2)
# Test a simple equation
self.assertAlmostEqual(