not a number double

679 512MB

why
distance+=Math.sqrt(Math.pow((double)wiersz_analiz owany[i],(double)2)-Math.pow((double)czyNajblizszySasiad[i],(double)2));

returns NaN

thank YOU

Jul 8 '07 #1

Subscribe Post Reply

3359

JosAH

11,448

Expert 8TB

why
distance+=Math.sqrt(Math.pow((double)wiersz_analiz owany[i],(double)2)-Math.pow((double)czyNajblizszySasiad[i],(double)2));

returns NaN

thank YOU

Remember the poor men's debugger System.out.println()? Apply it.
(hint: negative values don't go well for the Math.sqrt() method).

kind regards,

Jos

Jul 8 '07 #2

odefta

Correct.
make a loop and ...
System,out.println(czyNajblizszySasiad[i])

Remember the poor men's debugger System.out.println()? Apply it.
(hint: negative values don't go well for the Math.sqrt() method).

kind regards,

Jos

Jul 9 '07 #3

oll3i

679

512MB

i did system.out.printlns and the values are correct they are 0 ,1 ,2 or 3
because test data are rows consisted of 0 1 2 or 3 values

Jul 9 '07 #4

JosAH

11,448

Expert 8TB

i did system.out.printlns and the values are correct they are 0 ,1 ,2 or 3
because test data are rows consisted of 0 1 2 or 3 values

For all the operands of your expression print out all the operands and the
values of the evaluated (sub) expressions. a NaN (Not a Number) doesn't come
from nowhere.

kind regards,

Jos

Jul 9 '07 #5

oll3i

679

512MB

Expand|Select|Wrap|Line Numbers

 
public double liczDystans(Integer[] czyNajblizszySasiad){

    for(int i=0;i<liczbaColumn;i++){

    dystans+=Math.sqrt(Math.pow((double)wiersz_analizowany[i],(double)2)-Math.pow((double)czyNajblizszySasiad[i],(double)2));
 
    System.out.println("wiersz_analizowany[i]="+wiersz_analizowany[i]);

    System.out.println("Math.pow((double)wiersz_analizowany[i],(double)2)"+Math.pow((double)wiersz_analizowany[i],(double)2));
 
    System.out.println("czyNajblizszySasiad[i]="+czyNajblizszySasiad[i]);

    System.out.println("Math.pow((double)czyNajblizszySasiad[i],(double)2)"+Math.pow((double)czyNajblizszySasiad[i],(double)2));
 
    System.out.println("dystans="+dystans);

    }

    return dystans;

}

System.out.println("Math.pow((double)wiersz_analiz owany[i],(double)2)"+Math.pow((double)wiersz_analizowany[i],(double)2));

and
System.out.println("Math.pow((double)czyNajblizszy Sasiad[i],(double)2)"+Math.pow((double)czyNajblizszySasiad[i],(double)2));

return a double sqrt

Math.sqrt(Math.pow((double)wiersz_analizowany[i],(double)2)-Math.pow((double)czyNajblizszySasiad[i],(double)2));

returns nan ?

Jul 10 '07 #6

oll3i

679

512MB

it may happen that in my for loop dystans is equal to NaN but what happens if i add a double to NaN does it still return NaN ?

Jul 10 '07 #7

r035198x

13,262

8TB

Expand|Select|Wrap|Line Numbers

public double liczDystans(Integer[] czyNajblizszySasiad){

    for(int i=0;i<liczbaColumn;i++){

    dystans+=Math.sqrt(Math.pow((double)wiersz_analizowany[i],(double)2)-Math.pow((double)czyNajblizszySasiad[i],(double)2));

    System.out.println("wiersz_analizowany[i]="+wiersz_analizowany[i]);

    System.out.println("Math.pow((double)wiersz_analizowany[i],(double)2)"+Math.pow((double)wiersz_analizowany[i],(double)2));

    System.out.println("czyNajblizszySasiad[i]="+czyNajblizszySasiad[i]);

    System.out.println("Math.pow((double)czyNajblizszySasiad[i],(double)2)"+Math.pow((double)czyNajblizszySasiad[i],(double)2));

    System.out.println("dystans="+dystans);

    }

    return dystans;

}

System.out.println("Math.pow((double)wiersz_analiz owany[i],(double)2)"+Math.pow((double)wiersz_analizowany[i],(double)2));

and
System.out.println("Math.pow((double)czyNajblizszy Sasiad[i],(double)2)"+Math.pow((double)czyNajblizszySasiad[i],(double)2));

return a double sqrt

Math.sqrt(Math.pow((double)wiersz_analizowany[i],(double)2)-Math.pow((double)czyNajblizszySasiad[i],(double)2));

returns nan ?

Print the arguments you're passing to Math.pow as well.
I'm sure you have this open while doing this.

Jul 10 '07 #8

JosAH

11,448

Expert 8TB

it may happen that in my for loop dystans is equal to NaN but what happens if i add a double to NaN does it still return NaN ?

Yes, any operator yields NaN or false when at least one of the operands equals
Nan. Even NaN == NaN is false as well as NaN != NaN. It's Not a Number ;-)

kind regards,

Jos

Jul 10 '07 #9

oll3i

679

512MB

i changed it to

dystans=Math.sqrt(Math.pow((double)wiersz_analizow any[0],(double)2)-Math.pow((double)czyNajblizszySasiad[0],(double)2)+
Math.pow((double)wiersz_analizowany[1],(double)2)-Math.pow((double)czyNajblizszySasiad[1],(double)2) +
Math.pow((double)wiersz_analizowany[2],(double)2)-Math.pow((double)czyNajblizszySasiad[2],(double)2)+
Math.pow((double)wiersz_analizowany[3],(double)2)-Math.pow((double)czyNajblizszySasiad[3],(double)2)+
Math.pow((double)wiersz_analizowany[4],(double)2)-Math.pow((double)czyNajblizszySasiad[4],(double)2)+
Math.pow((double)wiersz_analizowany[5],(double)2)-Math.pow((double)czyNajblizszySasiad[5],(double)2)+
Math.pow((double)wiersz_analizowany[6],(double)2)-Math.pow((double)czyNajblizszySasiad[6],(double)2)+
Math.pow((double)wiersz_analizowany[7],(double)2)-Math.pow((double)czyNajblizszySasiad[7],(double)2)+
Math.pow((double)wiersz_analizowany[8],(double)2)-Math.pow((double)czyNajblizszySasiad[8],(double)2)+
Math.pow((double)wiersz_analizowany[9],(double)2)-Math.pow((double)czyNajblizszySasiad[9],(double)2)+
Math.pow((double)wiersz_analizowany[10],(double)2)-Math.pow((double)czyNajblizszySasiad[10],(double)2)+
Math.pow((double)wiersz_analizowany[11],(double)2)-Math.pow((double)czyNajblizszySasiad[11],(double)2)+
Math.pow((double)wiersz_analizowany[12],(double)2)-Math.pow((double)czyNajblizszySasiad[12],(double)2)+
Math.pow((double)wiersz_analizowany[13],(double)2)-Math.pow((double)czyNajblizszySasiad[13],(double)2)+
Math.pow((double)wiersz_analizowany[14],(double)2)-Math.pow((double)czyNajblizszySasiad[14],(double)2)+
Math.pow((double)wiersz_analizowany[15],(double)2)-Math.pow((double)czyNajblizszySasiad[15],(double)2)+
Math.pow((double)wiersz_analizowany[16],(double)2)-Math.pow((double)czyNajblizszySasiad[16],(double)2)+
Math.pow((double)wiersz_analizowany[17],(double)2)-Math.pow((double)czyNajblizszySasiad[17],(double)2)+
Math.pow((double)wiersz_analizowany[18],(double)2)-Math.pow((double)czyNajblizszySasiad[18],(double)2)+
Math.pow((double)wiersz_analizowany[19],(double)2)-Math.pow((double)czyNajblizszySasiad[19],(double)2)
);

but still distance is 0.0 or NaN Math.pow returns correct numbers i checked that it's sqrt that returns NaN or 0.0 where the result should be
eg 6.2 (first row of my test data)i counted

Jul 10 '07 #10

JosAH

11,448

Expert 8TB

i changed it to

dystans=Math.sqrt(Math.pow((double)wiersz_analizow any[0],(double)2)-Math.pow((double)czyNajblizszySasiad[0],(double)2)+
Math.pow((double)wiersz_analizowany[1],(double)2)-Math.pow((double)czyNajblizszySasiad[1],(double)2) +
Math.pow((double)wiersz_analizowany[2],(double)2)-Math.pow((double)czyNajblizszySasiad[2],(double)2)+
Math.pow((double)wiersz_analizowany[3],(double)2)-Math.pow((double)czyNajblizszySasiad[3],(double)2)+
Math.pow((double)wiersz_analizowany[4],(double)2)-Math.pow((double)czyNajblizszySasiad[4],(double)2)+
Math.pow((double)wiersz_analizowany[5],(double)2)-Math.pow((double)czyNajblizszySasiad[5],(double)2)+
Math.pow((double)wiersz_analizowany[6],(double)2)-Math.pow((double)czyNajblizszySasiad[6],(double)2)+
Math.pow((double)wiersz_analizowany[7],(double)2)-Math.pow((double)czyNajblizszySasiad[7],(double)2)+
Math.pow((double)wiersz_analizowany[8],(double)2)-Math.pow((double)czyNajblizszySasiad[8],(double)2)+
Math.pow((double)wiersz_analizowany[9],(double)2)-Math.pow((double)czyNajblizszySasiad[9],(double)2)+
Math.pow((double)wiersz_analizowany[10],(double)2)-Math.pow((double)czyNajblizszySasiad[10],(double)2)+
Math.pow((double)wiersz_analizowany[11],(double)2)-Math.pow((double)czyNajblizszySasiad[11],(double)2)+
Math.pow((double)wiersz_analizowany[12],(double)2)-Math.pow((double)czyNajblizszySasiad[12],(double)2)+
Math.pow((double)wiersz_analizowany[13],(double)2)-Math.pow((double)czyNajblizszySasiad[13],(double)2)+
Math.pow((double)wiersz_analizowany[14],(double)2)-Math.pow((double)czyNajblizszySasiad[14],(double)2)+
Math.pow((double)wiersz_analizowany[15],(double)2)-Math.pow((double)czyNajblizszySasiad[15],(double)2)+
Math.pow((double)wiersz_analizowany[16],(double)2)-Math.pow((double)czyNajblizszySasiad[16],(double)2)+
Math.pow((double)wiersz_analizowany[17],(double)2)-Math.pow((double)czyNajblizszySasiad[17],(double)2)+
Math.pow((double)wiersz_analizowany[18],(double)2)-Math.pow((double)czyNajblizszySasiad[18],(double)2)+
Math.pow((double)wiersz_analizowany[19],(double)2)-Math.pow((double)czyNajblizszySasiad[19],(double)2)
);

but still distance is 0.0 or NaN Math.pow returns correct numbers i checked that it's sqrt that returns NaN or 0.0 where the result should be
eg 6.2 (first row of my test data)i counted

Basically you're doing:

Expand|Select|Wrap|Line Numbers

Math.sqrt(Math.pow(x, 2)-Math.pow(y, 2))

(shouldn't that - be a +?)

Note that when |x| < |y| the square root doesn't exist.
Also note that the IEEE/459 floating point format knows about *two* zeros: +0
and -0; the square root of -0 is also a NaN if I'm not mistaken.

kind regards,

Jos

ps. no insult intended, but when you want your software to be maintained,
worked on etc. in an international environment, English variable names are to
be preferred. Really, I've been there, done that.

Jul 10 '07 #11

r035198x

13,262

8TB

Basically you're doing:

Expand|Select|Wrap|Line Numbers

Math.sqrt(Math.pow(x, 2)-Math.pow(y, 2))

(shouldn't that - be a +?)

Note that when |x| < |y| the square root doesn't exist.
Also note that the IEEE/459 floating point format knows about *two* zeros: +0
and -0; the square root of -0 is also a NaN if I'm not mistaken.

kind regards,

Jos

ps. no insult intended, but when you want your software to be maintained,
worked on etc. in an international environment, English variable names are to
be preferred. Really, I've been there, done that.

You've written software in (what's the Dutch language called) before?

Jul 10 '07 #12

oll3i

679

512MB

usually i use english names for variables but it's only college project so ...

Jul 10 '07 #13

oll3i

679

512MB

it's Euclidean Distance i'm counting should be -

Jul 10 '07 #14

JosAH

11,448

Expert 8TB

You've written software in (what's the Dutch language called) before?

Yep, and my instructor and professor kicked that habit out of me when I was a
youngster ;-)

The Dutch speak Dutch (who'd have thought it!) Afrikaans and Flemish and
Surinaams are all related. (the Flemish even claim that their language *is*
Dutch and the Dutch speak a dialect, which I think is true).

kind regards,

Jos

Jul 10 '07 #15

Similar topics

random number code

by: Jason | last post by:

Hi, I need a way to use random numbers in c++. In my c++ project, when using the mingw compiler I used a mersenne twister that is publicly available and this did its job well. Now I have...

C / C++

Newbye quetion: Why a double can store more number than a long ?

by: jose luis fernandez diaz | last post by:

Hi, My OS is: cronos:jdiaz:tmp>uname -a HP-UX cronos B.11.11 U 9000/800 820960681 unlimited-user license I compile in 64-bits mode the program below:

C / C++

RFC: clc-compliant pseudo-random number generator

by: Ben Pfaff | last post by:

One issue that comes up fairly often around here is the poor quality of the pseudo-random number generators supplied with many C implementations. As a result, we have to recommend things like...

C / C++

Trouble calculating 5th root of a given number using C

by: Kishor | last post by:

Hi Friends Please help me to write a C program to find the 5th (fifth) root of a given number. Ex:(1) Input : 32 Output : 5th root of 32 is 2 Ex:(1) Input : 243 Output : 5th root of 243 is...

C / C++

Floating Point Random Number Generator

by: Peteroid | last post by:

I know how to use rand() to generate random POSITIVE-INTEGER numbers. But, I'd like to generate a random DOUBLE number in the range of 0.0 to 1.0 with resolution of a double (i.e., every possible...

.NET Framework

Number type conversion

by: Pavils Jurjans | last post by:

Hello, I am somewhat lost in the implicit/expicit possible/impossible type casting in C#... I need to write a class, which among other things, must have wat to read a numeric value type, and...

C# / C Sharp

Variable of type DOUBLE converts number strangely.

by: John | last post by:

I'm new to C and I know this is probably one of those "most commonly mis-interpreted as a problem", newcomer type of question, but for this code: double x; printf("Enter number:");...

C / C++

How to use std::cout to output a char as a number?

by: Dancefire | last post by:

Hi, everyone It might be a simple question, but I really don't know the answer. char c = '1'; cout << c; The above code will only output a '1' rather than 0x31; If I use int cast, it can...

C / C++

Rounding a floating point number

by: jacob navia | last post by:

Hi "How can I round a number to x decimal places" ? This question keeps appearing. I would propose the following solution #include <float.h> #include <math.h>

C / C++

Check for whole number in template function.

by: Matthias | last post by:

Dear newsgroup. I want to write a template function which accepts either integer or floating point numbers. If a certain result is not a whole number and if the template parameter is an...

C / C++

Migrating Website to Cloud - Emmanuel Katto

by: emmanuelkatto | last post by:

Hi All, I am Emmanuel katto from Uganda. I want to ask what challenges you've faced while migrating a website to cloud. Please let me know. Thanks! Emmanuel

General

Looking to do Android software development, any suggestions? Is flutter better?

by: nemocccc | last post by:

hello, everyone, I want to develop a software for my android phone for daily needs, any suggestions?

General

Is that possible of reading the .csv file in column wise and the column have different lengths ?

by: Sonnysonu | last post by:

This is the data of csv file 1 2 3 1 2 3 1 2 3 1 2 3 2 3 2 3 3 the lengths should be different i have to store the data by column-wise with in the specific length. suppose the i have to...

C / C++

What is ONU?

by: marktang | last post by:

ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However,...

General

Changing the language in Windows 10

by: Hystou | last post by:

Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can...

Windows Server

Problem With Comparison Operator <=> in G++

by: Oralloy | last post by:

Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers,...

C / C++

Discussion: How does Zigbee compare with other wireless protocols in smart home applications?

by: tracyyun | last post by:

Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each...

General

AI Job Threat for Devs

by: agi2029 | last post by:

Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing,...

Career Advice

Access Europe - Using VBA to create a class based on a table - Wed 1 May

by: isladogs | last post by:

The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new...

Microsoft Access / VBA