computechi2¶
- class pydl.pydlutils.math.computechi2(bvec, sqivar, amatrix)[source]¶
Bases:
object
Solve the linear set of equations \(A x = b\) using SVD.
The attributes of this class are all read-only properties, implemented with
lazyproperty
.- Parameters
- bvec
numpy.ndarray
The \(b\) vector in \(A x = b\). This vector has length \(N\).
- sqivar
numpy.ndarray
The reciprocal of the errors in
bvec
. The name comes from the square root of the inverse variance, which is what this is.- amatrix
numpy.ndarray
The matrix \(A\) in \(A x = b\). The shape of this matrix is (\(N\), \(M\)).
- bvec
Initialize the object and perform initial computations.
Attributes Summary
(
ndarray
) The fit parameters, \(x\), in \(A x = b\).(
float
) The \(\chi^2\) value of the fit.(
ndarray
) The covariance matrix.(
int
) The degrees of freedom of the fit.(
ndarray
) The variances of the fit.(
ndarray
) The evaluated best-fit at each point.Attributes Documentation
- acoeff¶
(
ndarray
) The fit parameters, \(x\), in \(A x = b\). This vector has length \(M\).
- chi2¶
(
float
) The \(\chi^2\) value of the fit.
- covar¶
(
ndarray
) The covariance matrix. The shape of this matrix is (\(M\), \(M\)).
- dof¶
(
int
) The degrees of freedom of the fit. This is the number of values ofbvec
that havesqivar
> 0 minus the number of fit paramaters, which is equal to \(M\).
- var¶
(
ndarray
) The variances of the fit. This is identical to the diagonal of the covariance matrix. This vector has length \(M\).
- yfit¶
(
ndarray
) The evaluated best-fit at each point. This vector has length \(N\).