Adding Polynomials Rule #25
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lib/rules/collect-like-terms.js
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| null, {implicit: true} | ||
| ) | ||
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| return term |
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You'll want to flatten this term before you return it so that this will handle cases like 2 x y + 3 x y
| // e.g 2x + 2x + 4 + 6 | ||
| // coefficient map: {'x': [[2 node] [2 node]} | ||
| // constants: [[4 node] [6 node]] | ||
| const {constants, coefficientMap} = getCoefficientsAndConstants(node) |
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If we run COLLECT_LIKE_TERMS first then we shouldn't have to do any grouping.
test/rules_test.js
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| @@ -205,6 +205,14 @@ describe('rules', () => { | |||
| ['2x + 7y + 5 + 3y + 9x + 11', '(2 x + 9 x) + (7 y + 3 y) + (5 + 11)'], | |||
| ]) | |||
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| suite('add polynomials', rules.ADD_POLYNOMIAL_TERMS, [ | |||
| ['2x + 2x + 2 + 4', '4 x + (2 + 4)'], | |||
| ['2x + 2y', '2 x + 2 y'], | |||
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This one fails b/c the pattern match returns false. We should have better error handling for this, see #27.
test/rules_test.js
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| ['2x + 2x + 2 + 4', '4 x + (2 + 4)'], | ||
| ['2x + 2y', '2 x + 2 y'], | ||
| ['2x + 3x + 2y + 3y', '5 x + 5 y'], | ||
| ['-2y + 2x - 3x^2', '-2y + 2x - 3x^2'], |
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Same reason as the other failure.
lib/.#matcher.js
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| @@ -0,0 +1 @@ | |||
| [email protected] | |||
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Can you add these files to your global .gitignore?
test/rules_test.js
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| ['2x + 2y', '2 x + 2 y'], | ||
| ['2x + 3x + 2y + 3y', '5 x + 5 y'], | ||
| ['-2y + 2x - 3x^2', '-2y + 2x - 3x^2'], | ||
| ['-2y + 3y', '1 y'], |
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You may want to add some cases that include terms with multiple variables factors or factors with exponents and definitely some with subtraction.
lib/rules/collect-like-terms.js
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| @@ -84,6 +85,10 @@ const getVariableFactorName = (node) => { | |||
| } | |||
| } | |||
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| var alphabetize = function(variable) { | |||
| return variable.split('').sort().join('') | |||
| } | |||
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This isn't being called anywhere.
test/rules_test.js
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| ['-2y + 3y', '1 y'], | ||
| ['3 xy + 2 xy', '5 xy'], | ||
| ['3 xy - 2 xy + x^2y^2', '1 (x^2 y^2) + 1 xy'], | ||
| ['2 x y + 2 y x', '4 (x y)'], |
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This should be '2 x y + 2 y x', '4 x y'.
test/rules_test.js
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| ['2x + 3x + 2y + 3y', '5 x + 5 y'], | ||
| ['-2y + 3y', '1 y'], | ||
| ['3 xy + 2 xy', '5 xy'], | ||
| ['3 xy - 2 xy + x^2y^2', '1 (x^2 y^2) + 1 xy'], |
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Can you change these to use x y instead of xy? Also,
x^2y^2 --> 1 (x^2 y^2)
should probably be
x^2y^2 --> 1 x^2 y^2
This will require calling `flattenOperands` on `term` before returning it from the rewrite function of `ADD_POLYNOMIAL_TERMS`.
lib/rules/collect-like-terms.js
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| @@ -192,4 +194,72 @@ const COLLECT_LIKE_TERMS = defineRule( | |||
| } | |||
| ) | |||
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| export const ADD_POLYNOMIAL_TERMS = defineRule( | |||
| // MATCH PATTERN | |||
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minor nit... this should be // MATCH FUNCTION.
lib/rules/collect-like-terms.js
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| }, | ||
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| // REWRITE PATTERN |
lib/rules/collect-like-terms.js
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| // TODO: find a better way to specify the location | ||
| // [[5 node]] | ||
| const newCoeffNode = | ||
| build.numberNode(newCoeff, null, null) |
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This can be numberNode(newCoeff) now.
test/rules_test.js
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| @@ -110,7 +110,7 @@ describe('rules', () => { | |||
| ['x * -1', '-x'], | |||
| ['(x + 1) * -1', '-(x + 1)'], | |||
| ['x^((x + 1) * -1)', 'x^-(x + 1)'], | |||
| ['2x * 2 * -1', '2 x * -2'], | |||
| //['2x * 2 * -1', '2 x * -2'], | |||
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@aliang8 looks good. Thanks for making those changes. |
Added
addingPolynomialrule incollect-like-terms.js. Can move to a separate file. Added some test cases.Should we leave it as
1 yin-2y + 3yor should we change it toy? Also added comments in the code, let me know if it is good or if I should remove it!