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I'm calculating software development cost.

I don't know what do to with given formula so I need explanation. 

  C=aLb

Where    
    C = Costs  
    L= size  (Line of code in thousand lines of code e.g 400)
    a and b are constants

Constants are as follows at link:

Constants

            E = 2.4 * (400)1.05 = 1295.31 PM
            D = 2.5 * (1295.31)0.38=38.07 PM

How the value of E = 1295.31 is came?
Also how to use C=aLb formula?

epimorphic
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Hemlata
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  • As you have written the formula the constants $a$ and $b$ are redundant. They could be multiplied to make a single constant. That is a clue that you are not reading the formula correctly. – Ross Millikan Mar 21 '20 at 21:37

1 Answers1

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I think the formula should be $C=aL^b$, not $C=aLb$. If you look at your first example, where $L=400$, $a=2.4$ and $b=1.05$, you have

$400^{1.05} = 539.7131$

$C = 2.4 \times (400)^{1.05} = 2.4 \times 539.7131 = 1295.3114$

which matches the value in the example.

To use the formula, take the number of lines of code, divide this by $1,000$ to get $L$, raise this to the power of the constant $b$ to get $L^b$, then multiply this by the constant $a$ to get $aL^b$.

gandalf61
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  • Thank you so much. So may I know that I must divide lines of code by 1,000? So if I've 200 (two hundred) lines of code – Hemlata Mar 21 '20 at 14:16
  • @Hemlata The explanation you quoted below the formula in your post says that $L$ is measured in thousands of lines of code. So if you have $200$ lines of codes than your value for $L$ will be $\frac{200}{1000} = 0.2$. If you want to know why $L$ is measured in thousands of lines of code or why the formula takes the form it does, then you will have to go back to the source of the formula - I am only interpreting the information that you provided. – gandalf61 Mar 21 '20 at 14:58
  • Thank you so much. have a nice day :-) – Hemlata Mar 21 '20 at 15:03
  • @Hemlata: in essence $a$ represents the cost to write $1000$ lines of code. The exponent $b$ reflects the fact that as a project becomes bigger the cost goes up faster than the number of lines of code. This can be because it is harder for one person to keep track of all the pieces of the program, or because it takes more than one person to do the job and they spend time coordinating their efforts, or the requirements for a larger program are more complex and take more time to understand, or whatever. It is somebody's model for the cost of a job, which may match your experience or not. – Ross Millikan Mar 21 '20 at 21:40
  • @RossMillikan project wise there are different constants so we can estimate duration and efforts to accomplish the project. I've doubt that how to determine lines of code. Should I consider physical lines or only logical lines of code? – Hemlata Mar 22 '20 at 15:29
  • @RossMillikan And yes I'm working alone so I've doubt I mentioned above in comment, also when I convert cost USD to INR I'm getting too much higher or lower cost. – Hemlata Mar 22 '20 at 15:38