compute the function for 3 variables

src/lib/isValid.ts

@@ -0,0 +1,3 @@
+export default (a) => {
+    return !( a  && !isNaN(a))
+}

src/lib/threeVariables.ts

@@ -1,10 +1,41 @@
+import Toast from 'react-native-simple-toast'
 export default (matrix: number[]) => {
         const roots = []
 
+        // replace the respective column
+        const xMatrix = formMatrixColumn(matrix,0)
+        const yMatrix = formMatrixColumn(matrix,1)
+        const zMatrix = formMatrixColumn(matrix,2)
 
+        const determinant = Determinant(matrix)
+        const xdeterminant = Determinant(xMatrix)
+        const ydeterminant = Determinant(yMatrix)
+        const zdeterminant = Determinant(zMatrix)
 
+       if( determinant == 0) {
+           Toast.showWithGravity('There is no solution.', Toast.SHORT, Toast.CENTER)
+       } else {
+        roots.push(xdeterminant/determinant)
+        roots.push(ydeterminant/determinant)
+        roots.push(zdeterminant/determinant)
+       }
+        return roots
+}
 
+function Determinant(matrix: number[]) {
+    return ( (matrix[0][0] * matrix[1][1] * matrix[2][2]) +  (matrix[0][1] * matrix[1][2] * matrix[2][0]) + (matrix[0][2] * matrix[1][0] * matrix[2][1]))
+    - ( (matrix[2][0] * matrix[1][1] * matrix[0][2]) +  (matrix[2][1] * matrix[1][2] * matrix[0][0]) + (matrix[2][2] * matrix[1][0] * matrix[0][1]))
+}
 
+function formMatrixColumn(matrix: number[], index: number){
+    let clone =  JSON.parse(JSON.stringify(matrix))
 
-        return roots
+    clone.forEach(item => {
+        item[index] = item[3]
+    })
+
+    console.log(clone)
+
+
+    return clone
 }

src/views/example/cubic-equation/cubic-equation-screen.tsx

@@ -6,6 +6,7 @@ import { color } from "../../../theme"
 import { Header } from '../../shared/header'
 import { TextField } from '../../shared/text-field'
 import { Button } from '../../shared/button'
+import isNotValid from '../../../lib/isValid'
 import { NavigationScreenProps } from "react-navigation"
 import SolveCubic from '../../../lib/cubic'
 
@@ -94,7 +95,7 @@ export class CubicEquation extends React.Component<CubicEquationScreenProps, Sta
 
   solve = async () => {
     const { a, b , c , d } = this.state
-    if(isNaN(a) || isNaN(b) || isNaN(c) || isNaN(d)){
+    if(isNotValid(a) || isNotValid(b) || isNotValid(c) || isNotValid(d)){
        return;
     }
 
@@ -175,7 +176,7 @@ export class CubicEquation extends React.Component<CubicEquationScreenProps, Sta
                <Button preset="solve" text="Clear" onPress={this.clear} />
               </View>
            </View>
-           <View style={{ justifyContent: 'space-around', alignItems: 'center', flex:0.2}}>
+           <View style={{ justifyContent: 'space-around', alignItems: 'center', flex: 0.2}}>
             {
               roots && roots.map((item, index) => {
                 const ind = index + 1

src/views/example/linear-equation/linear-equation-screen.tsx

@@ -6,6 +6,7 @@ import { color } from "../../../theme"
 import Toast from 'react-native-simple-toast'
 import { Header } from '../../shared/header'
 import { Button } from '../../shared/button'
+import isNotValid from '../../../lib/isValid'
 import { TextField } from '../../shared/text-field'
 import { NavigationScreenProps } from "react-navigation"
 
@@ -94,7 +95,7 @@ export class LinearEquation extends React.Component<LinearEquationScreenProps, S
 
   solve = async () => {
     const { a, b, c  } = this.state
-    if(isNaN(a) || isNaN(b) || isNaN(c) ){
+    if(isNotValid(a) || isNotValid(b) || isNotValid(c) ){
       Toast.showWithGravity('The input should be a number.', Toast.SHORT, Toast.CENTER)
        return;
     }

src/views/example/quadratic-equation/quadratic-equation-screen.tsx

@@ -7,6 +7,7 @@ import Toast from 'react-native-simple-toast'
 import { Button } from '../../shared/button'
 import { TextField } from '../../shared/text-field'
 import { Header } from '../../shared/header'
+import isNotValid from '../../../lib/isValid'
 import { NavigationScreenProps } from "react-navigation"
 import QuadracticSolve from '../../../lib/quadratic'
 
@@ -95,9 +96,9 @@ export class QuadraticEquation extends React.Component<QuadraticEquationScreenPr
   state = initialState
   solve = async () => {
     const { a, b , c  } = this.state
-    if(isNaN(a) || isNaN(b) || isNaN(c)){
+    if(isNotValid(a) || isNotValid(b) || isNotValid(c)){
       Toast.showWithGravity('The input should be a number.', Toast.SHORT, Toast.CENTER)
-       return
+      return
     }
 
 
@@ -106,6 +107,7 @@ export class QuadraticEquation extends React.Component<QuadraticEquationScreenPr
 
   }
 
+
   clear = () => {
     this.setState(initialState)
   }

src/views/example/three-linear-equation/three-linear-equation-screen.tsx

@@ -2,10 +2,13 @@ import * as React from "react"
 import { ViewStyle, TextStyle, View , Dimensions} from "react-native"
 import { Text } from "../../shared/text"
 import { color } from "../../../theme"
+import Toast from 'react-native-simple-toast'
 import { Header } from '../../shared/header'
 import { Button } from '../../shared/button'
 import { TextField } from '../../shared/text-field'
 import { NavigationScreenProps } from "react-navigation"
+import isNotValid from '../../../lib/isValid'
+import ThreeVariableSolver from '../../../lib/threeVariables'
 
 export interface ThreeLinearEquationScreenProps extends NavigationScreenProps<{}> {
 }
@@ -47,10 +50,70 @@ const ButtonView: ViewStyle = {
   margin: 20, 
   justifyContent: 'space-between'
 }
+interface State {
+  x1: string,
+  y1: string,
+  z1: string,
+  w1: string,
+  x2: string,
+  y2: string,
+  z2: string,
+  w2: string,
+  x3: string,
+  y3: string,
+  z3: string,
+  w3: string,
+  roots: string[]
+}
+
+
+const initialState = {
+  x1: null,
+  y1: null,
+  z1: null,
+  w1: null,
+  x2: null,
+  y2: null,
+  z2: null,
+  w2: null,
+  x3: null,
+  y3: null,
+  z3: null,
+  w3: null,
+  roots: null
+}
+
+const variable = {
+  0: "x",
+  1: "y",
+  2: "z"
+}
+export class ThreeLinearEquation extends React.Component<ThreeLinearEquationScreenProps, State> {
+  state = initialState
+
+  solve = async () => {
+    const matrix = []
+    const { x1, x2, x3, y1, y2, y3, z1, z2, z3, w1, w2, w3 } = this.state
+    if(isNotValid(x1) || isNotValid(x2) || isNotValid(x3) || isNotValid(y1) || isNotValid(y2) || isNotValid(y3) || isNotValid(z1) || isNotValid(z2) || isNotValid(z3) || isNotValid(w1) || isNotValid(w2) || isNotValid(w3)){
+      Toast.showWithGravity('The input should be a number.', Toast.SHORT, Toast.CENTER)
+       return
+    }
+
+    matrix.push([Number(x1),Number(y1),Number(z1),Number(w1)])
+    matrix.push([Number(x2),Number(y2),Number(z2),Number(w2)])
+    matrix.push([Number(x3),Number(y3),Number(z3),Number(w3)])
+    const roots = await ThreeVariableSolver(matrix)
+    this.setState({ roots })
+
+  }
+
+  clear = () => {
+    this.setState(initialState)
+  }
 
-export class ThreeLinearEquation extends React.Component<ThreeLinearEquationScreenProps, {}> {
   render () {
     const { goBack } = this.props.navigation
+    const { x1, x2, x3, y1, y2, y3, z1, z2, z3, w1, w2, w3, roots } = this.state
     return (
       <View style={ROOT}>
         <Header  
@@ -60,87 +123,118 @@ export class ThreeLinearEquation extends React.Component<ThreeLinearEquationScre
           leftIcon="chevron-left"
           onLeftPress={() => goBack()}
            />
-           <View style={{flex: 0.6, justifyContent: 'space-around'}} >
+           <View style={{flex: 0.7, justifyContent: 'space-around'}} >
             <View style={InputView}>
                 <TextField 
                   style={Input} 
+                  value={x1}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={x1 => this.setState({ x1})}
                 />
                 <Text style={textStyle}> x +</Text>
                 <TextField 
                   style={Input} 
+                  value={y1}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={y1 => this.setState({y1})}
                 />
                 <Text style={textStyle}> y +</Text>
                 <TextField 
                   style={Input} 
+                  value={z1}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={z1 => this.setState({z1})}
                 />
                 <Text style={textStyle}> z =</Text>
                 <TextField 
                   style={Input} 
+                  value={w1}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={w1 => this.setState({w1})}
                 />  
            </View>
            <View style={InputView}>
                 <TextField 
                   style={Input} 
+                  value={x2}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={x2 => this.setState({ x2})}
                 />
                 <Text style={textStyle}> x +</Text>
                 <TextField 
                   style={Input} 
+                  value={y2}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={y2 => this.setState({y2})}
                 />
                 <Text style={textStyle}> y +</Text>
                 <TextField 
                   style={Input} 
+                  value={z2}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={z2 => this.setState({z2})}
                 />
                 <Text style={textStyle}> z =</Text>
                 <TextField 
                   style={Input} 
+                  value={w2}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={w2 => this.setState({w2})}
                 />  
            </View>
            <View style={InputView}>
                 <TextField 
                   style={Input} 
+                  value={x3}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={x3 => this.setState({x3})}
                 />
                 <Text style={textStyle}> x +</Text>
                 <TextField 
                   style={Input} 
+                  value={y3}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={y3 => this.setState({y3})}
                 />
                 <Text style={textStyle}> y +</Text>
                 <TextField 
                   style={Input} 
+                  value={z3}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={z3 => this.setState({z3})}
                 />
                 <Text style={textStyle}> z =</Text>
                 <TextField 
                   style={Input} 
+                  value={w3}
                   inputStyle={inputStyle}
                   keyboardType={'numeric'}
+                  onChangeText={w3 => this.setState({w3})}
                 />  
            </View>
            <View style={ButtonView}>
-              <Button preset="solve" text="Solve" />
-              <Button preset="solve" text="Clear" />
+           <Button preset="solve" text="Solve" onPress={this.solve} />
+              <Button preset="solve" text="Clear" onPress={this.clear} />
            </View>
            </View>
+           <View style={{ justifyContent: 'center', alignItems: 'center', flex: 0.3}}>
+            {
+              roots && roots.map((item, index) => {
+                  return <Text key={index} style={textStyle}>{variable[index] + " = " + item}</Text>
+              })
+            }
+            </View>
       </View>
     )
   }

src/views/example/two-linear-equation/two-linear-equation-screen.tsx

@@ -6,6 +6,7 @@ import { Header } from '../../shared/header'
 import { Button } from '../../shared/button'
 import Toast from 'react-native-simple-toast'
 import { TextField } from '../../shared/text-field'
+import isNotValid from '../../../lib/isValid'
 import { NavigationScreenProps } from "react-navigation"
 import TwoVariableSolver from '../../../lib/twoVariables'
 
@@ -80,7 +81,7 @@ export class TwoLinearEquation extends React.Component<TwoLinearEquationScreenPr
   state = initialState
   solve = async () => {
     const { x1, x2 , y1, y2, z1, z2  } = this.state
-    if(isNaN(x1) || isNaN(x2) || isNaN(y1) || isNaN(y2) || isNaN(z2) || isNaN(z1)){
+    if(isNotValid(x1) || isNotValid(x2) || isNotValid(y1) || isNotValid(y2) || isNotValid(z2) || isNotValid(z1)){
       Toast.showWithGravity('The input should be a number.', Toast.SHORT, Toast.CENTER)
        return
     }