Re: Some problems with numerical computation

[Liam Groener]

On Jan 22, 2012, at 10:16 PM, asha g wrote:

I have sorted the brackets and now get 2.2182e-11 which is far from 3.7746.

What could be the problem ?

Asha

 

 

On Sun, Jan 22, 2012 at 10:07 PM, asha g <address@hidden> wrote:

I did the following calculation by using a calculator . This is what I get with that :

A = 12/11 = 1.09

A1= 1.2

B = 3/11 = 0.272

h2 = 0.003523506

a = 3.083

b= -8.9696

c = 9.5909

d1 = -4.606

ee = 0.90151

f(1) = (-215.81 +627.872-671.363 +322.42-63.1057 ) / 0.0035235

= 0.0133/0.0035235 = 3.7746 

I hope you can sort this problem for me soon.

Thanks

Asha

 

You have some brackets in the wrong plave

f(1) = (a*V(1))+(b*V(2))+(c*V(3))+(d1*V(4))+(ee*V(5))/h2;

should be

f(1) = (a*V(1) +b*V(2) +c*V(3) +d1*V(4)+ee*V(5))/h2;

doug 

This is a precision problem in your calculator calculation. Octave uses double precission in it's internal calculations. By default, output is rounded to 5 significant figures. To output to full precision, enter the command: format long

Try repeating your calculator calculations using:

a =  3.08333333333333

b = -8.96969696969697

c =  9.59090909090909

d1 = -4.60606060606061

ee =  0.901515151515151

Liam G.