I just have of about 14 points as a data
I need to fiting them in a polynomial called Redlich- kister

in the form

y=x(1-x)∑(a0+a1(2x-1)+a2(2x-1)^2+a3(2x-1)^3)

I tried to solve it in FORTRAN with least square but i dint got a good answer for that

I got a program for solving the normal one as

a0+a1(2x-1)+a2(2x-1)^2+a3(2x-1)^3)

thankssssssss

2. Originally Posted by Abraham
I just have of about 14 points as a data
I need to fiting them in a polynomial called Redlich- kister

in the form

y=x(1-x)∑(a0+a1(2x-1)+a2(2x-1)^2+a3(2x-1)^3)

I tried to solve it in FORTRAN with least square but i dint got a good answer for that

I got a program for solving the normal one as

a0+a1(2x-1)+a2(2x-1)^2+a3(2x-1)^3)

thankssssssss
Why not post this data.

CB

3. Originally Posted by CaptainBlack
Why not post this data.

CB
Thanks for yr reply , I dont need to fit the only the data i have but i wana kindly to know how to solve that equation (kister eq.) by least square and find the concern cofficients
the data is as following

0.011 0.0218 0.037 0.0861 0.053 0.1654 0.061 0.2433 0.066 0.3101 0.069 0.374 0.072 0.4207 0.073 0.5003 0.07 0.5691 0.069 0.6326 0.067 0.7214 0.061 0.8072 0.049 0.86550.022 0.9573

4. Originally Posted by Abraham
Thanks for yr reply , I dont need to fit the only the data i have but i wana kindly to know how to solve that equation (kister eq.) by least square and find the concern cofficients
the data is as following

0.011 0.0218 0.037 0.0861 0.053 0.1654 0.061 0.2433 0.066 0.3101 0.069 0.374 0.072 0.4207 0.073 0.5003 0.07 0.5691 0.069 0.6326 0.067 0.7214 0.061 0.8072 0.049 0.86550.022 0.9573
that is fitting the data!

i recently implemented this myself (no you cannot have the code, sorry). wikipedia has the OLS equation:

Linear regression - Wikipedia, the free encyclopedia

5. THanks for yr help
I did answer the Qs and I found my mistake was on least square procedures ( just one iteration index missing ) not on the linear equations system solver

so thanks for yr help