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  • calculix data visualizor using QT

    - by Ann
    include "final1.h" include "ui_final1.h" include include include ifndef GL_MULTISAMPLE define GL_MULTISAMPLE 0x809D endif define numred 100 define numgrn 10 define numblu 6 final1::final1(QWidget *parent) : QGLWidget(parent) { setFormat(QGLFormat(QGL::SampleBuffers)); rotationX = -38.0; rotationY = -58.0; rotationZ = 0.0; scaling = .05; // glPolygonMode(GL_FRONT_AND_BACK,GL_FILL); //createGradient(); createGLObject(); } final1::~final1() { makeCurrent(); glDeleteLists(glObject, 1); } void final1::paintEvent(QPaintEvent * /* event */) { QPainter painter(this); draw(); } void final1::mousePressEvent(QMouseEvent *event) { lastPos = event-pos(); } void final1::mouseMoveEvent(QMouseEvent *event) { GLfloat dx = GLfloat(event-x() - lastPos.x()) / width(); GLfloat dy = GLfloat(event-y() - lastPos.y()) / height(); if (event->buttons() & Qt::LeftButton) { rotationX += 180 * dy; rotationY += 180 * dx; update(); } else if (event->buttons() & Qt::RightButton) { rotationX += 180 * dy; rotationZ += 180 * dx; update(); } lastPos = event->pos(); } void final1::createGLObject() { makeCurrent(); GLfloat f1[150],f2[150],f3[150],length=0; qreal size=2; int k=1,a,b,c,d,e,f,g,h,element_node_no=0; GLfloat x,y,z; QString str1,str2,str3,str4,str5,str6,str7,str8; int red,green,blue,index=1,displacement; int LUT[1000][3]; for(red=100;red glShadeModel(GL_SMOOTH); glObject = glGenLists(1); glNewList(glObject, GL_COMPILE); // qglColor(QColor(255, 239, 191)); glLineWidth(1.0); QLinearGradient linearGradient(0, 0, 100, 100); linearGradient.setColorAt(0.0, Qt::red); linearGradient.setColorAt(0.2, Qt::green); linearGradient.setColorAt(1.0, Qt::black); //renderArea->setBrush(linearGradient); //glColor3f(1,0,0);pow((f1[e]-f1[a]),2) QFile file("/home/41407/input1.txt"); if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) return; QTextStream in(&file); while (!in.atEnd()) { QString line = in.readLine(); if(k<=125) { str1= line.section(',', 1, 1); str2=line.section(',', 2, 2); str3=line.section(',', 3, 3); x=str1.toFloat(); y=str2.toFloat(); z=str3.toFloat(); f1[k]=x; f2[k]=y; f3[k]=z; /* glBegin(GL_TRIANGLES); // glColor3f(LUT[k][0],LUT[k][1],LUT[k][2]); //QColorAt();//setPointSize(size); glVertex3f(x,y,z); glEnd();*/ } else if(k>125) { element_node_no=0; qCount(line.begin(),line.end(),',',element_node_no); // printf("\n%d",element_node_no); str1= line.section(',', 1, 1); str2=line.section(',', 2, 2); str3=line.section(',', 3, 3); str4= line.section(',', 4, 4); str5=line.section(',', 5, 5); str6=line.section(',', 6, 6); str7= line.section(',', 7, 7); str8=line.section(',', 8, 8); a=str1.toInt(); b=str2.toInt(); c=str3.toInt(); d=str4.toInt(); e=str5.toInt(); f=str6.toInt(); g=str7.toInt(); h=str8.toInt(); glBegin(GL_POLYGON); glPolygonMode(GL_FRONT_AND_BACK,GL_FILL); //brush.setColor(Qt::black);//setColor(QColor::black()); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); // pmp.setBrush(gradient); glVertex3f(f1[a],f2[a] ,f3[a]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[b],f2[b] ,f3[b]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[c],f2[c] ,f3[c]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[d],f2[d] ,f3[d]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[a],f2[a] ,f3[a]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); //glEnd(); //glBegin(GL_LINE_LOOP); glVertex3f(f1[e],f2[e] ,f3[e]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[f],f2[f] ,f3[f]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[g],f2[g], f3[g]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[h],f2[h], f3[h]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[d],f2[d] ,f3[d]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[a],f2[a] ,f3[a]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glEnd(); glBegin(GL_POLYGON); //glVertex3f(f1[a],f2[a] ,f3[a]); glVertex3f(f1[e],f2[e] ,f3[e]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[h],f2[h], f3[h]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); //glVertex3f(f1[d],f2[d] ,f3[d]); glVertex3f(f1[g],f2[g], f3[g]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[c],f2[c] ,f3[c]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[f],f2[f] ,f3[f]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glVertex3f(f1[b],f2[b] ,f3[b]); glColor3f(LUT[k][0],LUT[k][1],LUT[k++][2]); glEnd(); /*length=sqrt(pow((f1[e]-f1[a]),2)+pow((f2[e]-f2[a]),2)+pow((f3[e]-f3[a]),2)); printf("\n%d",length);*/ } k++; } glEndList(); file.close(); k=1; QFile file1("/home/41407/op.txt"); if (!file1.open(QIODevice::ReadOnly | QIODevice::Text)) return; QTextStream in1(&file1); k=1; while (!in1.atEnd()) { QString line = in1.readLine(); // if(k<=125) { str1= line.section(' ', 1, 1); x=str1.toFloat(); str2=line.section(' ', 2, 2); y=str2.toFloat(); str3=line.section(' ', 3, 3); z=str3.toFloat(); displacement=sqrt(pow( (x-f1[k]),2)+pow((y-f2[k]),2)+pow((z-f3[k]),2)); //printf("\n %d : %d",k,displacement); glBegin(GL_POLYGON); //glColor3f(LUT[displacement][0],LUT[displacement][1],LUT[displacement][2]); glVertex3f(f1[k],f2[k],f3[k]); glEnd(); a1[k]=x+f1[k]; a2[k]=y+f2[k]; a3[k]=z+f3[k]; //printf("\nc: %f %f %f",x,y,z); //printf("\nf: %f %f %f",f1[k],f2[k],f3[k]); //printf("\na: %f %f %f",a1[k],a2[k],a3[k]); } k++; glEndList(); } } void final1::draw() { glPushAttrib(GL_ALL_ATTRIB_BITS); glMatrixMode(GL_PROJECTION); glPushMatrix(); glLoadIdentity(); GLfloat x = 3.0 * GLfloat(width()) / height(); glOrtho(-x, +x, -3.0, +3.0, 4.0, 15.0); glMatrixMode(GL_MODELVIEW); glPushMatrix(); glLoadIdentity(); glTranslatef(0.0, 0.0, -10.0); glScalef(scaling, scaling, scaling); glRotatef(rotationX, 1.0, 0.0, 0.0); glRotatef(rotationY, 0.0, 1.0, 0.0); glRotatef(rotationZ, 0.0, 0.0, 1.0); glEnable(GL_MULTISAMPLE); glCallList(glObject); glMatrixMode(GL_MODELVIEW); glPopMatrix(); glMatrixMode(GL_PROJECTION); glPopMatrix(); glPopAttrib(); } /*uint final1::colorAt(int x) { generateShade(); QPolygonF pts = m_hoverPoints->points(); for (int i=1; i < pts.size(); ++i) { if (pts.at(i-1).x() <= x && pts.at(i).x() >= x) { QLineF l(pts.at(i-1), pts.at(i)); l.setLength(l.length() * ((x - l.x1()) / l.dx())); return m_shade.pixel(qRound(qMin(l.x2(), (qreal(m_shade.width() - 1)))), qRound(qMin(l.y2(), qreal(m_shade.height() - 1)))); } } return 0;*/ //final1:: //} /*void final1::createGLObject() { makeCurrent(); //QPainter painter; QPixmap pm(20, 20); QPainter pmp(&pm); pmp.fillRect(0, 0, 10, 10, Qt::blue); pmp.fillRect(10, 10, 10, 10, Qt::lightGray); pmp.fillRect(0, 10, 10, 10, Qt::darkGray); pmp.fillRect(10, 0, 10, 10, Qt::darkGray); pmp.end(); QPalette pal = palette(); pal.setBrush(backgroundRole(), QBrush(pm)); //setAutoFillBackground(true); setPalette(pal); //GLfloat f1[150],f2[150],f3[150],a1[150],a2[150],a3[150]; int k=1,a,b,c,d,e,f,g,h; //int p=0; GLfloat x,y,z; int displacement; QString str1,str2,str3,str4,str5,str6,str7,str8; int red,green,blue,index=1; int LUT[8000][3]; for(red=0;red //glShadeModel(GL_LINE); glObject = glGenLists(1); glNewList(glObject, GL_COMPILE); //qglColor(QColor(120,255,210)); glLineWidth(1.0); //glColor3f(1,0,0); QFile file("/home/41407/input.txt"); if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) return; QTextStream in(&file); while (!in.atEnd()) { //glColor3f(LUT[k][0],LUT[k][1],LUT[k][2]); QString line = in.readLine(); if(k<=125) { //printf("\nline :%c",line); str1= line.section(',', 1, 1); str2=line.section(',', 2, 2); str3=line.section(',', 3, 3); x=str1.toFloat(); y=str2.toFloat(); z=str3.toFloat(); f1[k]=x; f2[k]=y; f3[k]=z; //printf("\nf: %f %f %f",f1[k],f2[k],f3[k]); } else if(k125) //for(p=0;p<6;p++) { //glColor3f(LUT[k][0],LUT[k][1],LUT[k][2]); update(); str1= line.section(',', 1, 1); str2=line.section(',', 2, 2); str3=line.section(',', 3, 3); str4= line.section(',', 4, 4); str5=line.section(',', 5, 5); str6=line.section(',', 6, 6); str7= line.section(',', 7, 7); str8=line.section(',', 8, 8); a=str1.toInt(); b=str2.toInt(); c=str3.toInt(); d=str4.toInt(); e=str5.toInt(); f=str6.toInt(); g=str7.toInt(); h=str8.toInt(); //for (p = 0; p < 6; p++) { // glBegin(GL_LINE_WIDTH); //glColor3f(LUT[126][0],LUT[126][1],LUT[126][2]); //update(); //glNormal3fv(&n[p][0]); //glVertex3f(f1[i],f2[i],f3[i]); glVertex3fv(&v[faces[i][1]][0]); glVertex3fv(&v[faces[i][2]][0]); glVertex3fv(&v[faces[i][3]][0]); //glEnd(); //} glBegin(GL_LINE_LOOP); //glColor3f(p*20,p*20,p); glColor3f(1,0,0); glVertex3f(f1[a],f2[a] ,f3[a]); //painter.fillRect(QRectF(f1[a],f2[a] ,f3[a], 2), Qt::magenta); glVertex3f(f1[b],f2[b] ,f3[b]); glVertex3f(f1[c],f2[c] ,f3[c]); glVertex3f(f1[d],f2[d] ,f3[d]); glVertex3f(f1[a],f2[a] ,f3[a]); glVertex3f(f1[e],f2[e] ,f3[e]); glVertex3f(f1[f],f2[f] ,f3[f]); glVertex3f(f1[g],f2[g], f3[g]); glVertex3f(f1[h],f2[h], f3[h]); glVertex3f(f1[d],f2[d] ,f3[d]); glVertex3f(f1[a],f2[a] ,f3[a]); //glColor3f(1,0,0); //QLinearGradient ( f1[a], f2[a], f1[b], f2[b] ); glEnd(); glBegin(GL_LINES); //glNormal3fv(&n[p][0]); //glColor3f(LUT[k][0],LUT[k][1],LUT[k][2]); glVertex3f(f1[e],f2[e] ,f3[e]); glVertex3f(f1[h],f2[h], f3[h]); glVertex3f(f1[g],f2[g], f3[g]); glVertex3f(f1[c],f2[c] ,f3[c]); glVertex3f(f1[f],f2[f] ,f3[f]); glVertex3f(f1[b],f2[b] ,f3[b]); glEnd(); } } k++; } glEndList(); qglColor(QColor(239, 255, 191)); glLineWidth(1.0); glColor3f(0,1,0); k=1; QFile file1("/home/41407/op.txt"); if (!file1.open(QIODevice::ReadOnly | QIODevice::Text)) return; QTextStream in1(&file1); k=1; while (!in1.atEnd()) { QString line = in1.readLine(); // if(k<=125) { str1= line.section(' ', 1, 1); x=str1.toFloat(); str2=line.section(' ', 2, 2); y=str2.toFloat(); str3=line.section(' ', 3, 3); z=str3.toFloat(); displacement=sqrt(pow( (x-f1[k]),2)+pow((y-f2[k]),2)+pow((z-f3[k]),2)); printf("\n %d : %d",k,displacement); glBegin(GL_POINT); glColor3f(LUT[displacement][0],LUT[displacement][1],LUT[displacement][2]); glVertex3f(x,y,z); glLoadIdentity(); glEnd(); a1[k]=x+f1[k]; a2[k]=y+f2[k]; a3[k]=z+f3[k]; //printf("\nc: %f %f %f",x,y,z); //printf("\nf: %f %f %f",f1[k],f2[k],f3[k]); //printf("\na: %f %f %f",a1[k],a2[k],a3[k]); } k++; glEndList(); } }*/ /*void final1::draw() { glPushAttrib(GL_ALL_ATTRIB_BITS); glMatrixMode(GL_PROJECTION); glPushMatrix(); glLoadIdentity(); GLfloat x = 3.0 * GLfloat(width()) / height(); glOrtho(-x, +x, -3.0, +3.0, 4.0, 15.0); glMatrixMode(GL_MODELVIEW); glPushMatrix(); glLoadIdentity(); glTranslatef(0.0, 0.0, -10.0); glScalef(scaling, scaling, scaling); glRotatef(rotationX, 1.0, 0.0, 0.0); glRotatef(rotationY, 0.0, 1.0, 0.0); glRotatef(rotationZ, 0.0, 0.0, 1.0); glEnable(GL_MULTISAMPLE); glCallList(glObject); glMatrixMode(GL_MODELVIEW); glPopMatrix(); glMatrixMode(GL_PROJECTION); glPopMatrix(); glPopAttrib(); }*/ I need to change the color of a portion of beam where pressure is applied.But I am not able to color the front end back phase.

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  • Add child to scene from within a class.

    - by Fecal Brunch
    Hi, I'm new to flash in general and have been writing a program with two classes that extend MovieClip (Stems and Star). I need to create a new Stems object as a child of the scene when the user stops dragging a Star object, but do not know how to reference the scene from within the Star class's code. I've tried passing the scene into the constructor of the Star and doing sometihng like: this.scene.addChild (new Stems ()); But apparently that's not how to do it... Below is the code for Stems and Stars, any advice would be appreciated greatly. package { import flash.display.MovieClip; import flash.events.*; import flash.utils.Timer; public class Stems extends MovieClip { public const centreX=1026/2; public const centreY=600/2; public var isFlowing:Boolean; public var flowerType:Number; public const outerLimit=210; public const innerLimit=100; public function Stems(fType:Number) { this.isFlowing=false; this.scaleX=this.scaleY= .0007* distanceFromCentre(this.x, this.y); this.setXY(); trace(distanceFromCentre(this.x, this.y)); if (fType==2) { gotoAndStop("Aplant"); } } public function distanceFromCentre(X:Number, Y:Number):int { return (Math.sqrt((X-centreX)*(X-centreX)+(Y-centreY)*(Y-centreY))); } public function rotateAwayFromCentre():void { var theX:int=centreX-this.x; var theY:int = (centreY - this.y) * -1; var angle = Math.atan(theY/theX)/(Math.PI/180); if (theX<0) { angle+=180; } if (theX>=0&&theY<0) { angle+=360; } this.rotation = ((angle*-1) + 90)+180; } public function setXY() { do { var tempX=Math.random()*centreX*2; var tempY=Math.random()*centreY*2; } while (distanceFromCentre (tempX, tempY)>this.outerLimit || distanceFromCentre (tempX, tempY)<this.innerLimit); this.x=tempX; this.y=tempY; rotateAwayFromCentre(); } public function getFlowerType():Number { return this.flowerType; } } } package { import flash.display.MovieClip; import flash.events.*; import flash.utils.Timer; public class Star extends MovieClip { public const sWide=1026; public const sTall=600; public var startingX:Number; public var startingY:Number; public var starColor:Number; public var flicker:Timer; public var canUpdatePos:Boolean=true; public const innerLimit=280; public function Star(color:Number, basefl:Number, factorial:Number) { this.setXY(); this.starColor=color; this.flicker = new Timer (basefl + factorial * (Math.ceil(100* Math.random ()))); this.flicker.addEventListener(TimerEvent.TIMER, this.tick); this.addEventListener(MouseEvent.MOUSE_OVER, this.hover); this.addEventListener(MouseEvent.MOUSE_UP, this.drop); this.addEventListener(MouseEvent.MOUSE_DOWN, this.drag); this.addChild (new Stems (2)); this.flicker.start(); this.updateAnimation(0, false); } public function distanceOK(X:Number, Y:Number):Boolean { if (Math.sqrt((X-(sWide/2))*(X-(sWide/2))+(Y-(sTall/2))*(Y-(sTall/2)))>innerLimit) { return true; } else { return false; } } public function setXY() { do { var tempX=this.x=Math.random()*sWide; var tempY=this.y=Math.random()*sTall; } while (distanceOK (tempX, tempY)==false); this.startingX=tempX; this.startingY=tempY; } public function tick(event:TimerEvent) { if (this.canUpdatePos) { this.setXY(); } this.updateAnimation(0, false); this.updateAnimation(this.starColor, false); } public function updateAnimation(color:Number, bright:Boolean) { var brightStr:String; if (bright) { brightStr="bright"; } else { brightStr="low"; } switch (color) { case 0 : this.gotoAndStop("none"); break; case 1 : this.gotoAndStop("N" + brightStr); break; case 2 : this.gotoAndStop("A" + brightStr); break; case 3 : this.gotoAndStop("F" + brightStr); break; case 4 : this.gotoAndStop("E" + brightStr); break; case 5 : this.gotoAndStop("S" + brightStr); break; } } public function hover(event:MouseEvent):void { this.updateAnimation(this.starColor, true); this.canUpdatePos=false; } public function drop(event:MouseEvent):void { this.stopDrag(); this.x=this.startingX; this.y=this.startingY; this.updateAnimation(0, false); this.canUpdatePos=true; } public function drag(event:MouseEvent):void { this.startDrag(false); this.canUpdatePos=false; } } }

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  • Factorising program not working. Help required.

    - by Ender
    I am working on a factorisation problem using Fermat's Factorization and for small numbers it is working well. I've been able to calculate the factors (getting the answers from Wolfram Alpha) for small numbers, like the one on the Wikipedia page (5959). Just when I thought I had the problem licked I soon realised that my program was not working when it came to larger numbers. The program follows through the examples from the Wikipedia page, printing out the values a, b, a2 and b2; the results printed for large numbers are not correct. I've followed the pseudocode provided on the Wikipedia page, but am struggling to understand where to go next. Along with the Wikipedia page I have been following this guide. Once again, as my Math knowledge is pretty poor I cannot follow what I need to do next. The code I am using so far is as follows: import java.math.BigInteger; /** * * @author AlexT */ public class Fermat { private BigInteger a, b; private BigInteger b2; private static final BigInteger TWO = BigInteger.valueOf(2); public void fermat(BigInteger N) { // floor(sqrt(N)) BigInteger tmp = getIntSqrt(N); // a <- ceil(sqrt(N)) a = tmp.add(BigInteger.ONE); // b2 <- a*a-N b2 = (a.multiply(a)).subtract(N); final int bitLength = N.bitLength(); BigInteger root = BigInteger.ONE.shiftLeft(bitLength / 2); root = root.add(b2.divide(root)).divide(TWO); // while b2 not square root while(!(isSqrt(b2, root))) { // a <- a + 1 a = a.add(BigInteger.ONE); // b2 <- (a * a) - N b2 = (a.multiply(a)).subtract(N); root = root.add(b2.divide(root)).divide(TWO); } b = getIntSqrt(b2); BigInteger a2 = a.pow(2); // Wrong BigInteger sum = (a.subtract(b)).multiply((a.add(b))); //if(sum.compareTo(N) == 0) { System.out.println("A: " + a + "\nB: " + b); System.out.println("A^2: " + a2 + "\nB^2: " + b2); //} } /** * Is the number provided a perfect Square Root? * @param n * @param root * @return */ private static boolean isSqrt(BigInteger n, BigInteger root) { final BigInteger lowerBound = root.pow(2); final BigInteger upperBound = root.add(BigInteger.ONE).pow(2); return lowerBound.compareTo(n) <= 0 && n.compareTo(upperBound) < 0; } public BigInteger getIntSqrt(BigInteger x) { // It returns s where s^2 < x < (s+1)^2 BigInteger s; // final result BigInteger currentRes = BigInteger.valueOf(0); // init value is 0 BigInteger currentSum = BigInteger.valueOf(0); // init value is 0 BigInteger sum = BigInteger.valueOf(0); String xS = x.toString(); // change input x to a string xS int lengthOfxS = xS.length(); int currentTwoBits; int i=0; // index if(lengthOfxS % 2 != 0) {// if odd length, add a dummy bit xS = "0".concat(xS); // add 0 to the front of string xS lengthOfxS++; } while(i < lengthOfxS){ // go through xS two by two, left to right currentTwoBits = Integer.valueOf(xS.substring(i,i+2)); i += 2; // sum = currentSum*100 + currentTwoBits sum = currentSum.multiply(BigInteger.valueOf(100)); sum = sum.add(BigInteger.valueOf(currentTwoBits)); // subtraction loop do { currentSum = sum; // remember the value before subtract // in next 3 lines, we work out // currentRes = sum - 2*currentRes - 1 sum = sum.subtract(currentRes); // currentRes++ currentRes = currentRes.add(BigInteger.valueOf(1)); sum = sum.subtract(currentRes); } while(sum.compareTo(BigInteger.valueOf(0)) >= 0); // the loop stops when sum < 0 // go one step back currentRes = currentRes.subtract(BigInteger.valueOf(1)); currentRes = currentRes.multiply(BigInteger.valueOf(10)); } s = currentRes.divide(BigInteger.valueOf(10)); // go one step back return s; } /** * @param args the command line arguments */ public static void main(String[] args) { Fermat fermat = new Fermat(); //Works //fermat.fermat(new BigInteger("5959")); // Doesn't Work fermat.fermat(new BigInteger("90283")); } } If anyone can help me out with this problem I'll be eternally grateful.

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  • Different results when applying function to equal values

    - by Johannes Stiehler
    I'm just digging a bit into Haskell and I started by trying to compute the Phi-Coefficient of two words in a text. However, I ran into some very strange behaviour that I cannot explain. After stripping everything down, I ended up with this code to reproduce the problem: let sumTup = (sumTuples°concat) frequencyLists let sumFixTup = (138, 136, 17, 204) putStrLn (show ((138, 136, 17, 204) == sumTup)) putStrLn (show (phi sumTup)) putStrLn (show (phi sumFixTup)) This outputs: True NaN 0.4574206676616167 So although the sumTupand sumFixTup show as equal, they behave differently when passed to phi. The definition of phi is: phi (a, b, c, d) = let dividend = fromIntegral(a * d - b * c) divisor = sqrt(fromIntegral((a + b) * (c + d) * (a + c) * (b + d))) in dividend / divisor

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  • Solving a math problem/expression, which is a string, in PHP

    - by Koning WWWWWWWWWWWWWWWWWWWWWWW
    The user can enter a math problem (expression) like 5 + 654, 6 ^ 24, 2!, sqrt(543), log(54), sin 5, sin(50). After some reformatting (e.g. change sin 5 into sin(5)), and doing an eval, PHP gives me the right result: $problem = "5 + 5324"; eval("$result = " . $problem); echo $problem . " = " . $result; However, this is quite unsafe: /* If you read this, please, plz don't be stupid and DO NOT EXECUTE this code!!!!! */ $problem = "shell_exec('rm -rf /')"; eval("$result = " . $problem); /* Nukes system */ echo $problem . " = " . $result; Can anyone point me in the right direction parsing and solving a math question like the examples above, which is safe? Thanks.

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  • MATLAB Heart Curve

    - by Arkapravo
    I am trying to get this in MATLAB, however I am not successful ! Any MATLAB gurus out there ? I guess simple commands should work, a program may not be needed. The error, I am getting is; >> t = -pi:0.1:pi; >> r = ((sin(t)*sqrt(cos(t)))*(sin(t) + (7/5))^(-1)) - 2*sin(t) + 2 ; ??? Error using ==> mtimes Inner matrix dimensions must agree.

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  • C#. Whats the fastest way to make an integer positive

    - by maxima120
    I asked wrong question previously and was swamped with negative votes... Let me try again... What is absolutely fastest way to make an int positive (given 50/50 distribution of pos/neg over time). To be nominated for an answer I will require MSIL analysis and not a guess or measuring of time with granny's watch... P.S. as one of variations I proposed i * i not because I wanted to do Sqrt(i * i) afterwards but because i will be used only once to be compared to a const. And if i * i will win competition I simply multiply the const.. Hence the following solution is valid: int trigger = realTrigger * realTrigger; i = SomeCalcs(); i = i * i; if(i < trigger) DoSomething(); P.P.S. pointless rant is not acceptable.. like: why do you need this, its BS! C# cannot tolerate developers like you!

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  • Find the closest vector

    - by Alexey Lebedev
    Hello! Recently I wrote the algorithm to quantize an RGB image. Every pixel is represented by an (R,G,B) vector, and quantization codebook is a couple of 3-dimensional vectors. Every pixel of the image needs to be mapped to (say, "replaced by") the codebook pixel closest in terms of euclidean distance (more exactly, squared euclidean). I did it as follows: class EuclideanMetric(DistanceMetric): def __call__(self, x, y): d = x - y return sqrt(sum(d * d, -1)) class Quantizer(object): def __init__(self, codebook, distanceMetric = EuclideanMetric()): self._codebook = codebook self._distMetric = distanceMetric def quantize(self, imageArray): quantizedRaster = zeros(imageArray.shape) X = quantizedRaster.shape[0] Y = quantizedRaster.shape[1] for i in xrange(0, X): print i for j in xrange(0, Y): dist = self._distMetric(imageArray[i,j], self._codebook) code = argmin(dist) quantizedRaster[i,j] = self._codebook[code] return quantizedRaster ...and it works awfully, almost 800 seconds on my Pentium Core Duo 2.2 GHz, 4 Gigs of memory and an image of 2600*2700 pixels:( Is there a way to somewhat optimize this? Maybe the other algorithm or some Python-specific optimizations.

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  • Solve equation from string to result in C

    - by Alexandre Cassagne
    Hi, I would like to know if anyone has info or experience on how to do something which sounds simple but doesn't look like it when trying to program it. The idea is : give a string containing an equation, such as : "2*x = 10" for example (this is simple, but it could get very complex, such as sqrt(54)*35=x^2; and so on....) and the program would return x = 5 and possibly give a log of how he got there. Is this doable ? If so, does anyone have a lead ? For info there is this site (http://www.numberempire.com/equationsolver.php) which does the same thing in PHP, but isn't open source. Thanks for any help !

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  • how to get output of a variable as float value

    - by jaskirat
    hi..i m having the follwing problem.. want to get the result in float suppose int a= convert.toint32(textbox1.text); int b= convert.toint32(textbox2.text); float ans= math.sqrt(a*b); label1.text= ans.tostring(); output.. a=7 b=3 ans should be= 4.582 but i get an error cannot implicitly convert type 'double' to 'float'. pls help..how can i get the float ans...

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  • Can bad stuff happen when dividing 1/a very small float?

    - by Jeremybub
    If I want to check that positive float A is less than the inverse square of another positive float B (in C99), could something go wrong if B is very small? I could imagine checking it like if(A<1/(B*B)) but if B is small enough, would this possibly result in infinity? If that were to happen, would the code still work correctly in all situations? in a similar vein, I might do if(1/A>B*B) Which might be slightly better because B*B might be zero if B is small (is this true?) Finally, a solution that I can't imagine being wrong is if(sqrt(1/A)>B) Which I don't think would ever result in zero division, but still might be problematic if A is close to zero. So basically, my questions are Can 1/X ever be infinity if X is greater than zero (but small)? Can X*X ever be zero if X is greater than zero? Will comparisons with infinity work the way I would expect them to?

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  • Interpolating 1D Gaussian into 2D Gaussian

    - by Drazick
    Let's say I have a 1D Gaussian function. Its length is 600 for that matter. I want to Interpolate it into 2D Gaussian of the size 600 X 600. This is the code I wrote (OTFx is the Gaussian Function, OTF - 2d Interpolated Function): [x, y] = meshgrid([-300:299], [-300:299]); r = sqrt((x .^ 2) + (y .^ 2)); OTF = interp1([-300:299], OTFx, r(:), 'spline'); OTF = reshape(OTF, [600, 600]); The problem is I get Overshoot at the end: How can I prevent it? Is there better Interpolating algorithm for Monotonic Descending Functions?

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  • Arrays- Square root of an Array and printing the result JAVA

    - by roger34
    Hello, The title says it all, really. I'm trying to get an array of (9) numbers squared then printed but I keep coming back with only one result - the number of numbers in the array squared- obviously not what I want. Thanks for any help. Ok, here is my terrible code so far. Trying to pass it to a method as well. public static void main ( String args[] ) { double[] nums = {126, 12.939, 795, 320.16, 110, 34.7676, 7773, 67, 567, 323}; System.out.println ("Square root is " +square); square(nums); } public static double square (double [] array) { double result; for( double i = 0; i < array.length ; i++ ) result = Math.sqrt(array[i]); return result; } }

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  • Fermat factorization method limit

    - by Fakrudeen
    I am trying to implement Fermat's factorization [Algorithm C in Art of computer programming Vol. 2]. Unfortunately in my edition [ISBN 81-7758-335-2], this algorithm is printed incorrectly. what should be the condition on factor-inner loop below? I am running the loop till y <= n [passed in as limit]. (if (< limit y) 0 (factor-inner x (+ y 2) (- r y) limit)) Is there anyway to avoid this condition altogether, as it will double the speed of loop? (define (factor n) (let ( ( square-root (inexact->exact (floor (sqrt n))) ) ) (factor-inner (+ (* 2 square-root) 1) 1 (- (* square-root square-root) n) n) ) ) (define (factor-inner x y r limit) (if (= r 0) (/ (- x y) 2) (begin (display x)(display " ")(display y)(display " ")(display r)(newline) ;(sleep-current-thread 1) (if (< r 0) (factor-inner (+ x 2) y (+ r x) limit) (if (< limit y) 0 (factor-inner x (+ y 2) (- r y) limit)) ) ) ) )

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  • iphone moving direction using accelerometer

    - by Ruchir Shah
    Hi, I want some help on UIAccelerometer class. I want to find some way to find out or distinguish when I wave iphone device from right-to-left and the left-to-right. I am getting x,y,z values as well as interval value. I am also getting velocity and distance calculated from normal physics rule. Distance = (prevDist + sqrt(pow((prevx - acceleration.x), 2) + pow((prevy - acceleration.y), 2) + pow((prevz - acceleration.z), 2))) Velocity = (Distance * timeintercal) { here distance means newdistance-prevdistance and timeinterval for that distance } When I am moving iphone device right-to-left then left-to-right I am getting total distance traveld in both direction and velocity at regular intervals. Can you help me how I can find out that I am moving iphone device left-to-right or right-to-left? Help would be appreciated. Thanks.

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  • Why might different computers calculate different arithmetic results in VB.NET?

    - by Eyal
    I have some software written in VB.NET that performs a lot of calculations, mostly extracting jpegs to bitmaps and computing calculations on the pixels like convolutions and matrix multiplication. Different computers are giving me different results despite having identical inputs. What might be the reason? Edit: I can't provide the algorithm because it's proprietary but I can provide all the relevant operations: ULong \ ULong (Turuncating division) Bitmap.Load("filename.bmp') (Load a bitmap into memory) Bitmap.GetPixel(Integer, Integer) (Get a pixel's brightness) Double + Double Double * Double Math.Sqrt(Double) Math.PI Math.Cos(Double) ULong - ULong ULong * ULong ULong << ULong List.OrderBy(Of Double)(Func) Hmm... Is it possible that OrderBy is using a non-stable QuickSort and that QuickSort is using a random pivot? Edit: Just tested, nope. The sort is stable.

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  • Gradient algororithm produces little white dots

    - by user146780
    I'm working on an algorithm to generate point to point linear gradients. I have a rough, proof of concept implementation done: GLuint OGLENGINEFUNCTIONS::CreateGradient( std::vector<ARGBCOLORF> &input,POINTFLOAT start, POINTFLOAT end, int width, int height,bool radial ) { std::vector<POINT> pol; std::vector<GLubyte> pdata(width * height * 4); std::vector<POINTFLOAT> linearpts; std::vector<float> lookup; float distance = GetDistance(start,end); RoundNumber(distance); POINTFLOAT temp; float incr = 1 / (distance + 1); for(int l = 0; l < 100; l ++) { POINTFLOAT outA; POINTFLOAT OutB; float dirlen; float perplen; POINTFLOAT dir; POINTFLOAT ndir; POINTFLOAT perp; POINTFLOAT nperp; POINTFLOAT perpoffset; POINTFLOAT diroffset; dir.x = end.x - start.x; dir.y = end.y - start.y; dirlen = sqrt((dir.x * dir.x) + (dir.y * dir.y)); ndir.x = static_cast<float>(dir.x * 1.0 / dirlen); ndir.y = static_cast<float>(dir.y * 1.0 / dirlen); perp.x = dir.y; perp.y = -dir.x; perplen = sqrt((perp.x * perp.x) + (perp.y * perp.y)); nperp.x = static_cast<float>(perp.x * 1.0 / perplen); nperp.y = static_cast<float>(perp.y * 1.0 / perplen); perpoffset.x = static_cast<float>(nperp.x * l * 0.5); perpoffset.y = static_cast<float>(nperp.y * l * 0.5); diroffset.x = static_cast<float>(ndir.x * 0 * 0.5); diroffset.y = static_cast<float>(ndir.y * 0 * 0.5); outA.x = end.x + perpoffset.x + diroffset.x; outA.y = end.y + perpoffset.y + diroffset.y; OutB.x = start.x + perpoffset.x - diroffset.x; OutB.y = start.y + perpoffset.y - diroffset.y; for (float i = 0; i < 1; i += incr) { temp = GetLinearBezier(i,outA,OutB); RoundNumber(temp.x); RoundNumber(temp.y); linearpts.push_back(temp); lookup.push_back(i); } for (unsigned int j = 0; j < linearpts.size(); j++) { if(linearpts[j].x < width && linearpts[j].x >= 0 && linearpts[j].y < height && linearpts[j].y >=0) { pdata[linearpts[j].x * 4 * width + linearpts[j].y * 4 + 0] = (GLubyte) j; pdata[linearpts[j].x * 4 * width + linearpts[j].y * 4 + 1] = (GLubyte) j; pdata[linearpts[j].x * 4 * width + linearpts[j].y * 4 + 2] = (GLubyte) j; pdata[linearpts[j].x * 4 * width + linearpts[j].y * 4 + 3] = (GLubyte) 255; } } lookup.clear(); linearpts.clear(); } return CreateTexture(pdata,width,height); } It works as I would expect most of the time, but at certain angles it produces little white dots. I can't figure out what does this. This is what it looks like at most angles (good) http://img9.imageshack.us/img9/5922/goodgradient.png But once in a while it looks like this (bad): http://img155.imageshack.us/img155/760/badgradient.png What could be causing the white dots? Is there maybe also a better way to generate my gradients if no solution is possible for this? Thanks

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  • python geometry help

    - by Enriquev
    Hello, I have the following problem, I am trying to find the following distances (F1 and F2): This is what I have as of now: def FindArrow(self, X1, Y1, X2, Y2, X3, Y3): self.X1 = float(X1) self.Y1 = float(Y1) self.X2 = float(X2) self.Y2 = float(Y2) self.X3 = float(X3) self.Y3 = float(Y3) #center coords of the circle self.Xc = None self.Yc = None #radius self.R = None #F1 and F2 self.FAB = None self.FBC = None #check if the coordinates are collinear invalide = self.X1 * (self.Y2 - self.Y3) + self.X2 * (self.Y3 - self.Y1) + self.X3 * (self.Y1 - self.Y2) if (invalide == 0): return #get the coords of the circle's center s = (0.5 * ((self.X2 - self.X3)*(self.X1 - self.X3) - (self.Y2 - self.Y3) * (self.Y3 - self.Y1))) / invalide self.Xc = 0.5 * (self.X1 + self.X2) + s * (self.Y2 - self.Y1) self.Yc = 0.5 * (self.Y1 + self.Y2) + s * (self.X1 - self.X2) #get the radius self.R = math.sqrt(math.pow(self.Xc - self.X1, 2) + math.pow(self.Yc - self.Y1, 2)) Until here everything seems to work, now what would be the next steps to get F1 and F2 ?

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  • Interesting AS3 hash situation. Is it really using strict equality as the documentation says?

    - by Triynko
    AS3 Code: import flash.utils.Dictionary; var num1:Number = Number.NaN; var num2:Number = Math.sqrt(-1); var dic:Dictionary = new Dictionary( true ); trace(num1); //NaN trace(num2); //NaN dic[num1] = "A"; trace( num1 == num2 ); //false trace( num1 === num2 ); //false trace( dic[num1] ); //A trace( dic[num2] ); //A Concerning the key comparison method... "The Dictionary class lets you create a dynamic collection of properties, which uses strict equality (===) for key comparison. When an object is used as a key, the object's identity is used to look up the object, and not the value returned from calling toString() on it." If Dictionary uses strict equality, as the documentation states, then how is it that num1 === num2 is false, and yet dic[num1] resolves to the same hash slot as dic[num2]?

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  • Constructor Type Coercion in C++

    - by Robert Mason
    Take the following class: class mytype { double num; public: mytype(int a) { num = sqrt(a); } void print() { cout << num; } } Say there is a method which takes a mytype: void foo(mytype a) { a.print(); } Is it legal c++ (or is there a way to implement this) to call foo(4), which would (in theory) output 2? From what I can glean you can overload type casts from a user defined class, but not to. Can constructor do this in a standards-compliant manner (assuming, of course, the constructor is not explicit). Hopefully there is a way to in the end have this legal: int a; cin >> a; foo(a); Note: this is quite obviously not the actual issue, but just an example for posting purposes. I can't just overload the function because of inheritance and other program-specific issues.

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  • What does the following FORTRAN code do?

    - by Jon Skeet
    C AREA OF A TRIANGLE WITH A STANDARD SQUARE ROOT FUNCTION C INPUT - CARD READER UNIT 5, INTEGER INPUT C OUTPUT - LINE PRINTER UNIT 6, REAL OUTPUT C INPUT ERROR DISPLAY ERROR OUTPUT CODE 1 IN JOB CONTROL LISTING READ (5, 501) IA, IB, IC 501 FORMAT (3I5) C IA, IB, AND IC MAY NOT BE NEGATIVE C FURTHERMORE, THE SUM OF TWO SIDES OF A TRIANGLE C IS GREATER THAN THE THIRD SIDE, SO WE CHECK FOR THAT, TOO IF (IA) 777, 777, 701 701 IF (IB) 777, 777, 702 702 IF (IC) 777, 777, 703 703 IF (IA+IB-IC) 777,777,704 704 IF (IA+IC-IB) 777,777,705 705 IF (IB+IC-IA) 777,777,799 777 STOP 1 C USING HERON'S FORMULA WE CALCULATE THE C AREA OF THE TRIANGLE 799 S = FLOATF (IA + IB + IC) / 2.0 AREA = SQRT( S * (S - FLOATF(IA)) * (S - FLOATF(IB)) * + (S - FLOATF(IC))) WRITE (6, 601) IA, IB, IC, AREA 601 FORMAT (4H A= ,I5,5H B= ,I5,5H C= ,I5,8H AREA= ,F10.2, + 13H SQUARE UNITS) STOP END plz i need to know soon!!!!!

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  • Efficient implementation of natural logarithm (ln) and exponentiation

    - by Donotalo
    Basically, I'm looking for implementation of log() and exp() functions provided in C library <math.h>. I'm working with 8 bit microcontrollers (OKI 411 and 431). I need to calculate Mean Kinetic Temperature. The requirement is that we should be able to calculate MKT as fast as possible and with as little code memory as possible. The compiler comes with log() and exp() functions in <math.h>. But calling either function and linking with the library causes the code size to increase by 5 Kilobytes, which will not fit in one of the micro we work with (OKI 411), because our code already consumed ~12K of available ~15K code memory. The implementation I'm looking for should not use any other C library functions (like pow(), sqrt() etc). This is because all library functions are packed in one library and even if one function is called, the linker will bring whole 5K library to code memory.

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  • Performance of: if (OBJECT_INSTANCE is TYPE)

    - by Axonn
    I am working both in C# and ActionScript 3. Both language are type-aware, so you can do verifications such as: if (some_object_instance is SomeClassName_ThatIs_SomeType) I'm doing these kind of verifications in a few places. Might be a dumb question, but I will ask it anyway, and I want answers from both camps, C# and ActionScript: What goes on behind the scenes? Is it Reflection? If is, isn't this a long verification which might degrade performance if done in thousands of loops? And by "degrade performance" I mean, is it more intensive than say if (Math.sqrt(8) > Math.sin(10))

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  • array, I/O file and standard deviation (c++)

    - by JohnWong
    double s_deviation(double data[],int cnt, double mean) { int i; double sum= 0; double sdeviation; double x; //x = mean(billy,a_size); for(i=0; i<cnt; i++) { sum += ((data[i]) - (mean)); } sdeviation = sqrt(sum/((double)cnt)); return sdeviation; } When I cout the result from this function, it gave me NaN. I tested the value of (mean) and data[i] using return data[i] and return mean they are valid. when i replaced mean with an actual number, the operation returned a finite number. but with mean as a variable, it produced NaH. I can't see anything wrong with my code at the moment. Again, I am sure mean, data are getting the right number based on those tests. Thank you

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