Fisher matrix calculation

 Posts: 25
 Joined: April 17 2007
 Affiliation: APC, Paris 7 / OBSPM
Fisher matrix calculation
Does the iCosmo web interface Fisher matrix calculation use a 2point or 4point derivative by default?

 Posts: 24
 Joined: October 20 2004
 Affiliation: LASTRO (EPFL)
 Contact:
Fisher matrix calculation
Hi Ivan,
The calculation on the web interface uses the 2point derivative.
The source code has the option to do both the 2point or 4point derivative, and you can download the source code here: http://www.icosmo.org/Initiative_Web/Tools.html
By default the source code does the calculation using the 2pointderivative, but this can be made more accurate by using a fiducial structure with:
fid = set_fiducial(calc_in={speed:0})
Cheers, Anais.
The calculation on the web interface uses the 2point derivative.
The source code has the option to do both the 2point or 4point derivative, and you can download the source code here: http://www.icosmo.org/Initiative_Web/Tools.html
By default the source code does the calculation using the 2pointderivative, but this can be made more accurate by using a fiducial structure with:
fid = set_fiducial(calc_in={speed:0})
Cheers, Anais.

 Posts: 1
 Joined: March 29 2010
 Affiliation: Med Univ Graz
Fisher matrix calculation
Dear Member,
I have studied the source to obtain the math schema how the fisher matrix is calculated. I discoverd that there are 2 methods. sne and boa. Do I assume correctly that the fisher matrix is calculated so?:
fisher = TRANSPOSE[DeriveMatrix] * INVERSE[covarianceMAtrix] * DeriveMatrix
Sorry for my stupid question: But what is the covariancematrix there? In teh source at boa the cov = INVERSE[fisher]. I am completely confused. Teh reson for my question are: in a book [Excel for chemists] there is written the attached picture (
and
).
CAN I SAY, that this P[i,j] is also the fisher matrix? But there I miss the covariance matrix. How is the covariacne matrix calculated? Thanks a lot for getting understand the fundamentals of the fisher calculation.
I have studied the source to obtain the math schema how the fisher matrix is calculated. I discoverd that there are 2 methods. sne and boa. Do I assume correctly that the fisher matrix is calculated so?:
fisher = TRANSPOSE[DeriveMatrix] * INVERSE[covarianceMAtrix] * DeriveMatrix
Sorry for my stupid question: But what is the covariancematrix there? In teh source at boa the cov = INVERSE[fisher]. I am completely confused. Teh reson for my question are: in a book [Excel for chemists] there is written the attached picture (
and
).
CAN I SAY, that this P[i,j] is also the fisher matrix? But there I miss the covariance matrix. How is the covariacne matrix calculated? Thanks a lot for getting understand the fundamentals of the fisher calculation.