// replace every x in tree by (x - vx) // i.e. replace fVar with (fvar - vx) private void translateX(ExpressionNode en, double vx, int varNo) { ExpressionValue left = en.getLeft(); ExpressionValue right = en.getRight(); // left tree if (left == fVars[varNo]) { try { // is there a constant number to the right? MyDouble num = (MyDouble) right; double temp; switch (en.getOperation()) { case ExpressionNode.PLUS: temp = num.getDouble() - vx; if (Kernel.isZero(temp)) { expression = expression.replaceAndWrap(en, fVars[varNo]); } else if (temp < 0) { en.setOperation(ExpressionNode.MINUS); num.set(-temp); } else { num.set(temp); } return; case ExpressionNode.MINUS: temp = num.getDouble() + vx; if (Kernel.isZero(temp)) { expression = expression.replaceAndWrap(en, fVars[varNo]); } else if (temp < 0) { en.setOperation(ExpressionNode.PLUS); num.set(-temp); } else { num.set(temp); } return; default: en.setLeft(shiftXnode(vx, varNo)); } } catch (Exception e) { en.setLeft(shiftXnode(vx, varNo)); } } else if (left instanceof ExpressionNode) { translateX((ExpressionNode) left, vx, varNo); } // right tree if (right == fVars[varNo]) { en.setRight(shiftXnode(vx, varNo)); } else if (right instanceof ExpressionNode) { translateX((ExpressionNode) right, vx, varNo); } }