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calculates the value of a Boltzmann function with parameters parlist at the position xdat
- Parameters
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xdat | position array |
parlist | parameter list The parameters are:
# parlist(0): background1
# parlist(1): background2
# parlist(2): central position
# parlist(3): width
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- Returns
- function value of a Boltzmann function that is y = (parlist(0) - parlist(1)) / (1+exp((x-parlist(2))/parlist(3))) + parlist(1)
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float | sinfo_new_boltz (float *xdat, float *parlist) |
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calculates the partial derivatives for a Boltzmann function with parameters parlist at position xdat
- Parameters
-
xdat | position array xdat |
parlist | parameter list The parameters are:
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parlist(0): background1
parlist(1): background2
parlist(2): central position
parlist(3): width
- Parameters
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dervs | derivative value of a Boltzmann function at\ position xdat: dervs dervs[0]: partial derivative by background1
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dervs[1]: partial derivative by background2
dervs[2]: partial derivative by central position
dervs[3]: partial derivative by the width
- Returns
- nothing, void
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void | sinfo_new_boltz_deriv (float *xdat, float *parlist, float *dervs) |
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makes a least-squares fit of a function to a set of data points.
- Parameters
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xdat | position, coordinates of data points. xdat is 2 dimensional: XDAT ( XDIM, NDAT ) |
xdim | dimension of fit |
ydat | data points |
wdat | weights for data points |
ndat | number of data points |
fpar | on input contains initial estimates of the parameters for non-linear fits, on output the fitted parameters. |
epar | contains estimates of the errors in fitted parameters |
mpar | logical mask telling which parameters are free (non-zero) and which parameters are fixed (0) |
npar | number of function parameters ( free + fixed ) |
tol | relative tolerance. sinfo_lsqfit stops when successive iterations fail to produce a decrement in reduced chi-squared less than tol. If tol is less than the minimum tolerance possible, tol will be set to this value. This means that maximum accuracy can be obtained by setting tol = 0.0. |
its | maximum number of iterations |
lab | mixing parameter, lab determines the initial weight of steepest descent method relative to the Taylor method lab should be a small value (i.e. 0.01). lab can only be zero when the partial derivatives are independent of the parameters. In fact in this case lab should be exactly equal to zero. |
- Returns
- number of iterations needed to achieve convergence according to tol. When this number is negative, the fitting was not continued because a fatal error occurred:
-1 too many free parameters, maximum is 32
-2 no free parameters
-3 not enough degrees of freedom
-4 maximum number of iterations too small to obtain
a solution which satisfies tol.
-5 diagonal of sinfo_matrix contains elements which
are zero
-6 determinant of the coefficient sinfo_matrix is zero
-7 square root of a negative number
this is a routine for making a least-squares fit of a function to a set of data points. The method used is described in: Marquardt, J.Soc.Ind.Appl.Math. 11. 431 (1963). This method is a mixture of the steepest descent method and the Taylor method.
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int | sinfo_new_lsqfit (float *xdat, int *xdim, float *ydat, float *wdat, int *ndat, float *fpar, float *epar, int *mpar, int *npar, float *tol, int *its, float *lab) |
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fits the beginning and end position of the slitlets by using non-linear least square fitting of a Boltzmann function fits a Boltzmann function to the slitlet edges exposed and indicated by the brightest emission lines.
- Parameters
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lineImage | emission line frame |
par | fit parameter data structure of fitted lines |
slit_pos | allocated dummy array for the slitlet positions [32][2] |
box_length | pixel length of the row box within the fit is done |
y_box | small box in spectral direction within the slitlet may lie. |
diff_tol | maximum tolerable difference of the resulting fit position with respect to the expected position. If difference is greater the expected position is taken. |
- Returns
- slit_pos: beginning and end position of the slitlets to sub-pixel accuracy
0 if it worked,
-1 if there was no line image given,
-2 if there were no line fit parameters given,
-3 if there was no dummy array for the slit positions
allocated
-4 if the given box length is impossible
-5 if the given y box length is impossible
-6 if the given difference tolerance is too small
-7 if there were no emission lines found in the first
image columns
-8 if not all slitlets could be found
fits the beginning and end position of the slitlets by using non-linear least square fitting of a Boltzmann function fits a Boltzmann function to the slitlet edges exposed and indicated by the brightest emission lines. To achieve this, the fit parameters are used to find the brightest emission line and to get its position for each column. The least squares fit is done by using a box smaller than the size of two slitlets
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int | sinfo_new_fit_slits_boltz (cpl_image *lineImage, FitParams **par, float **slit_pos, int box_length, float y_box, float diff_tol) |
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fits the beginning and end position of the slitlets by using non-linear least square fitting of a Boltzmann function
- Parameters
-
lineImage | emission line frame |
slit_pos | allocated dummy array for the slitlet positions [min32][2] |
box_length | pixel length of the row box within the fit is done |
y_box | small box in spectral direction within the slitlet may lie. |
low_pos | pixel positions in spectral direction between which the line should be located. |
high_pos | pixel positions in spectral direction between which the line should be located. |
- Returns
- slit_pos: beginning and end position of the slitlets to sub-pixel accuracy
0 if it worked,
-1 if it failed,
fits the beginning and end position of the slitlets by using non-linear least square fitting of a Boltzmann function fits a Boltzmann function to the slitlet edges exposed and indicated by the brightest emission lines. The slitlet is searched with user given positions. The least squares fit is done by using a box smaller than the size of two slitlets
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int | sinfo_new_fit_slits_boltz_single_line (cpl_image *lineImage, float **slit_pos, int box_length, float y_box, int low_pos, int high_pos) |
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its the beginning and end position of the slitlets by using non-linear least square fitting of a Boltzmann function
- Parameters
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lineImage | emission line frame |
slit_pos | estimation array for the slitlet positions [min32][2] |
box_length | pixel length of the row box within the fit is done |
y_box | small box in spectral direction within the slitlet may lie. |
diff_tol | tolerance on slitlets position |
low_pos | pixel positions in spectral direction between which the line should be located. |
high_pos | pixel positions in spectral direction between which the line should be located. |
- Returns
- slit_pos beginning and end position of the slitlets to sub-pixel accuracy
0 if it worked,
-1 if it failed,
- Note
- fits the beginning and end position of the slitlets by using non-linear least square fitting of a Boltzmann function fits a Boltzmann function to the slitlet edges exposed and indicated by the brightest emission lines. The slitlet is searched within user given positions. The least squares fit is done by using a box smaller than the size of two slitlets
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int | sinfo_new_fit_slits_boltz_with_estimate (cpl_image *lineImage, float **slit_pos, int box_length, float y_box, float diff_tol, int low_pos, int high_pos) |
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routines to determine the absolute positions of the slitlets out of an emission line frame