c++ - Can we assume any pair of following floating point arithmetic statements always produce identical result? -

-

Looking at the variables of floating points with arbitrary value, in c / c ++ 

  float a, b, c, d;   
 In the following statements, can we assume any pair of them, produce similar results?  
  Float result_1 = a + b + c + d - c; Float result_2 = a + b + c + (d - c); Float result_3 = a + b + d; In addition, there is no guarantee of the following decisions:  
  a + b - b == a    
 
 
 No, you can not accept it. I broke all three of your examples:  
  #include & lt; Iostream & gt; Int main () {Double A = 1, B = 1 e 100, C = 1a 100, D = 1, C2 = 1, D2 = -1, B2 = 1; Std :: cout & lt; & Lt; (A + b2 + c2 + d2 - c2 == a + b2 + c2 + (d2 - c2)) & lt; & Lt; "\ N" & lt; & Lt; (A + b2 + c + d - c == a + b2 + d) & lt; & Lt; "\ N" & lt; & Lt; (A == A + B-B); }   
 Output:  
 
 0   
  ==  and ! =  Always unsafe on floating point types because they have rounding errors.

Comments

Post a Comment

Popular posts from this blog

ios - Adding an SKSpriteNode to SKScene from a child SKSpriteNode -

-
I have a SKScene where I am adding an SKSpriteNode I have subclassed the SKSpriteNode class to create this node. In the subclass I am defining some SKActions on Sprite. What do I want to do when the end of this phantom ends the SKAction sequence, then I add a new Prayer node to this scene. How is this possible. The following code is mine: The code for the sequence is that I'm running on the Scansprinitode subclass (TEMissileNode): - SKAction * moveDown = [SKAction moveToY: Self.position.y - 20 Duration: 0.2]; SKAction * animation = [SKAction animateWithTextures: textures timePerFrame: time / 7]; SKAction * moveMissileProjectile = [SKAction Moving: Pointoffscreen Term: Time]; SKAction * group = [SKAction group: @ [animation, movement projectile]]; SKAction * Sequence = [SKAction Sequence: @ [Hilldown, Group, [SKAction removalFromParent]]]; [Self run action: sequence]; From the main scene, I call those actions that execute these tasks TEMissileNode * missile = [tmissil...
Read more

Matlab transpose a table vector -

-
An embarrassing simple question seems to be, but how can I move a Matlab table vector? aTableT = aTable '; I tried a standard syntax for the simple interaction of a line vector to a line vector aTable : ATableT = reshape (aTable, 1, Height (aTable)); and aTableT = rot90 (aTable); According to the head, the last time table should work for table, see. However, I get this error code: Error type in using table / permit (line 396) Undefined function 'permute' for the input arguments. Error in rot 90 (line 29) b = magnitude (b, [2 1 3: ndims (a)]); NB: fliplr is not useful either pretty sure I have covered clear angles - any ideas? Thanks! Try changing your table into an array, move it, then back to a table In other words, try doing this: aTableArray = table2array (aTable); ATableT = array 2table (aTableArray. '); I have also read the document for rot90 , and it says that rot90 is definitely working for tables Do, and I find you...
Read more

c# - Textbox not clickable but editable -

-
I have a small form with 10 text boxes, I have set them in the correct tab order. I want them on my tab service I was wondering if there is a way to set the text box so that they can be selected for editing until they are tabbed. That is ... I do not want the end user to edit the text box to click on them, I just want to make them editable through tabu. this should do the trick public partial category poor text box: Text Box {Safe Override Zero WndProc (Ref: Message Message) {if (m.msg == (Int) WM.LBUTTONDOWN) {Return; // mount down events} base.WndProc (ref m); }} Window message enum can be found. How to do this without anherizing: text box : class EatMouseDown: netwindows {safe override zero WndProc (ref message message) {if (m.msg == (int) WM.LBUTTONDOWN) {return; } Base.WandProc (Ref M); }} Safe Override Zero Onload (EventEurge E) {base.OnLoad (e); How to do this without any part: left a clean part, whatever is important, this can be a buggy but it works R...
Read more