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Some additional helper functions #7

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144 changes: 144 additions & 0 deletions lib/__test__/__snapshots__/query.test.js.snap
Original file line number Diff line number Diff line change
Expand Up @@ -177,6 +177,45 @@ exports[`query getCoefficientsAndConstants 3x^2 * 2x^2 1`] = `
}
`;

exports[`query getCoefficientsAndConstants x + 4 + 2^x + x 1`] = `
{
"others": [
{
"type": "Apply",
"op": "pow",
"args": [
{
"value": "2",
"type": "Number"
},
{
"type": "Identifier",
"name": "x"
}
]
}
],
"constants": [
{
"value": "4",
"type": "Number"
}
],
"coefficientMap": {
"x": [
{
"value": "1",
"type": "Number"
},
{
"value": "1",
"type": "Number"
}
]
}
}
`;

exports[`query getCoefficientsAndConstants x^3 + y^3 + x y z + 3 1`] = `
{
"others": [
Expand Down Expand Up @@ -210,6 +249,55 @@ exports[`query getCoefficientsAndConstants x^3 + y^3 + x y z + 3 1`] = `
}
`;

exports[`query getCoefficientsAndConstants z + 2*(y + x) + 4 + z 1`] = `
{
"others": [
{
"type": "Apply",
"op": "mul",
"args": [
{
"value": "2",
"type": "Number"
},
{
"type": "Apply",
"op": "add",
"args": [
{
"type": "Identifier",
"name": "y"
},
{
"type": "Identifier",
"name": "x"
}
]
}
]
}
],
"constants": [
{
"value": "4",
"type": "Number"
}
],
"coefficientMap": {
"z": [
{
"value": "1",
"type": "Number"
},
{
"value": "1",
"type": "Number"
}
]
}
}
`;

exports[`query getVariableFactors 2 x y z 1`] = `
[
{
Expand All @@ -236,6 +324,29 @@ exports[`query getVariableFactors 2x 1`] = `
]
`;

exports[`query getVariableFactors 2x^2 * y 1`] = `
[
{
"type": "Apply",
"op": "pow",
"args": [
{
"type": "Identifier",
"name": "x"
},
{
"value": "2",
"type": "Number"
}
]
},
{
"type": "Identifier",
"name": "y"
}
]
`;

exports[`query getVariableFactors 2x^2 1`] = `
[
{
Expand All @@ -255,6 +366,39 @@ exports[`query getVariableFactors 2x^2 1`] = `
]
`;

exports[`query getVariableFactors x^2 * 2/3 y^2 1`] = `
[
{
"type": "Apply",
"op": "pow",
"args": [
{
"type": "Identifier",
"name": "x"
},
{
"value": "2",
"type": "Number"
}
]
},
{
"type": "Apply",
"op": "pow",
"args": [
{
"type": "Identifier",
"name": "y"
},
{
"value": "2",
"type": "Number"
}
]
}
]
`;

exports[`query getVariableFactors x^2 1`] = `
[
{
Expand Down
40 changes: 34 additions & 6 deletions lib/__test__/query.test.js
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
import assert from 'assert'
import {parse} from 'math-parser'
import {parse, print} from 'math-parser'
import stringify from 'json-stable-stringify'

import * as query from '../query'
Expand Down Expand Up @@ -54,6 +54,8 @@ describe('query', () => {
'x^2',
'2x^2',
'2 x y z',
'2x^2 * y',
'x^2 * 2/3 y^2'
])

suite('getCoefficientsAndConstants', query.getCoefficientsAndConstants, [
Expand All @@ -65,7 +67,9 @@ describe('query', () => {
'x^3 + y^3 + x y z + 3',
'2/3 + 3 + cos(4)',
'3x^2 * 2x^2',
'2/3(x + 1)^1'
'2/3(x + 1)^1',
'x + 4 + 2^x + x',
'z + 2*(y + x) + 4 + z'
])

it('isVariableFactor', () => {
Expand Down Expand Up @@ -106,6 +110,27 @@ describe('query', () => {
assert(!query.isPolynomial(parse('1/x')))
})

it('hasCoeff', () => {
assert(query.hasCoeff(parse('2x')))
assert(query.hasCoeff(parse('2x^2')))
assert(query.hasCoeff(parse('2 x y z')))
assert(!query.hasCoeff(parse('2')))
assert(!query.hasCoeff(parse('x')))
})

it('negate', () => {
assert.equal(print(build.negate(parse('2'))), -2)
assert.equal(print(build.negate(parse('2x^2'))), '-2 x^2')
assert.equal(print(build.negate(parse('2xyz'))), '-2 xyz')
assert.equal(print(build.negate(parse('-2'))), 2)
assert.equal(print(build.negate(parse('-2x^2'))), '2 x^2')
assert.equal(print(build.negate(parse('-2x^2 y^2'))), '2 x^2 y^2')
assert.equal(print(build.negate(parse('2x^2 y^2'))), '-2 x^2 y^2')
assert.equal(print(build.negate(parse('2/3'))), '-2 / 3')
assert.equal(print(build.negate(parse('-2/3'))), '2 / 3')
assert.equal(print(build.negate(parse('(x+3)/3'))), '-(x + 3) / 3')
})

it('hasSameBase', () => {
assert(query.hasSameBase(parse('x^1'), parse('x^2')))
assert(query.hasSameBase(parse('(x+1)^2'), parse('(x+1)^x')))
Expand Down Expand Up @@ -262,10 +287,13 @@ describe('query', () => {
assert(!query.isRel(x))
})

it('isNumber', () => {
assert(query.isNumber(a))
assert(query.isNumber(parse('-2')))
assert(!query.isNumber(x))
it('isRationalNumber', () => {
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Maybe add some tests that check for factions and decimals.

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👍

assert(query.isRationalNumber(a))
assert(query.isRationalNumber(parse('-2')))
assert(query.isRationalNumber(parse('2/3')))
assert(query.isRationalNumber(parse('2.2')))
assert(!query.isRationalNumber(x))
assert(!query.isRationalNumber(parse('(2 + x)/2')))
})

it('getValue', () => {
Expand Down
22 changes: 22 additions & 0 deletions lib/build.js
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,8 @@
* Functions to build nodes
*/

const q = require('./query.js')

export const apply = (op, args, options = {}) => ({
type: 'Apply',
op: op,
Expand Down Expand Up @@ -56,3 +58,23 @@ export const parensNode = parens
export const numberNode = number
export const identifierNode = identifier
export const applyNode = apply

// e.g 3 -> -3, -3x -> 3x, x + 3 -> -(x + 3), 2/3 -> -2 / 3
export const negate = (node) => {
if (q.isNeg(node)) {
return node.args[0]
} else if (q.isAdd(node)) {
return neg(node)
} else if (q.isFraction(node)) {
return div(negate(q.getNumerator(node)), q.getDenominator(node))
} else if (q.isPolynomialTerm(node)) {
if (q.isNeg(q.getCoefficient(node))) {
return apply(
'mul',
[negate(q.getCoefficient(node)), ...node.args.slice(1)],
{implicit: node.implicit})
} else {
return neg(node)
}
}
}
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