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NAME:
SEGMENT_TEST.PRO
PURPOSE:
Check a spinmodel segment structure to ensure that the model parameters
b and c are consistent with the start and end times and
spin counts
CATEGORY:
TDAS
CALLING SEQUENCE:
segment_test,probe,segment,result
INPUTS:
probe: A single character probe letter (only used in output messages).
segment: A spinmodel_segment structure.
OUTPUTS:
result: 0 for failure, 1 for success
KEYWORDS:
None.
PROCEDURE:
Calls segment_interp_t to get spin count and spin phase at
segment start/end times.
Calls segment_interp_n to get sun pulse times of segment
start/end counts.
Cross check results of segment_interp_t and segment_interp_n,
verifying that interp_t and interp_n results are consistent
within modest tolerances (100 usec for times, 0.1 deg for
phase angles).
Check maxgap field against 4-hour threshold; large gaps are
likely a result of missing data.
EXAMPLE:
mptr=spinmodel_get_ptr('a')
sptr=(*mptr).segs_ptr
segment_test,'a',(*sptr)[0],result
Written by: Jim Lewis (jwl@ssl.berkeley.edu)
Change Date: 2007-10-08
(See themis/spin/segment_test.pro)
NAME:
SPINMODEL_GET_PTR.PRO
PURPOSE:
Returns a pointer to the spin model, specified by a single
letter probe designation ('a' through 'f'). This is to avoid
having to define the spinmodel common block all over the place.
CATEGORY:
TDAS
CALLING SEQUENCE:
model_ptr=spinmodel_get_ptr('a')
INPUTS:
probe: A scalar character, one of 'a' through 'f', specifying which model
pointer to return.
OUTPUTS:
model_ptr: The return value is a pointer to the specified spin model,
suitable for passing to the other spinmodel manipulation routines.
KEYWORDS:
None.
PROCEDURE:
Test probe argument for validity; return appropriate value from
the spinmodel_common block.
EXAMPLE:
model_ptr=spinmodel_get_ptr('a')
spinmodel_test,model_ptr
Written by: Jim Lewis (jwl@ssl.berkeley.edu)
Change Date: 2007-10-08
(See themis/spin/spinmodel_get_ptr.pro)
NAME:
SPINMODEL_INTERP_N.PRO
PURPOSE:
Given a spin model and spin count (or array of counts), calculate
the sun pulse time and spin period at each input count.
CATEGORY:
TDAS
CALLING SEQUENCE:
spinmodel_interp_n,model=modelptr,count=input_counts,$
time=output_times, spinper=output_spinper
INPUTS:
Model: pointer to a spinmodel structure
Count: A long integer (or long integer array) specifying the spin
count to use. If the input is a scalar, all outputs
will be scalars; otherwise, all outputs are arrays having
the same size as the input counts.
OUTPUTS:
spinper: Optional keyword parameter to receive spin period values.
time: Optional keyword parameter to receive sun pulse time
of each input count.
KEYWORDS:
/MODEL: Required input keyword argument, specifying a pointer to a
spinmodel structure.
/COUNT: Required input keyword argument specifying a time or array of times.
/SPINPER: Optional keyword argument to receive spin period values.
/TIME: Optional keyword argument to receive sun pulse times.
PROCEDURE:
Find the spinmodel segment containing the input spin count.
Invert phi(t) function to find time corresponding to this count.
Use b and c segment parameters to determine the spin period
at the sunpulse time.
EXAMPLE:
; Retrieve first 100 sun pulse times included in model for THA:
modelptr=spinmodel_get_ptr('a')
spinmodel_interp_n,model=modelptr,count=lindgen(100),time=output_times
(See themis/spin/spinmodel_interp_n.pro)
NAME:
SPINMODEL_INTERP_T.PRO
PURPOSE:
Given a spin model and time (or array of times), calculate
the spin count, spin phase, spin period, and time of last sun pulse
for each input time.
CATEGORY:
TDAS
CALLING SEQUENCE:
spinmodel_interp_t,model=modelptr,time=input_times,$
spincount=output_spincount, spinper=output_spinper,$
t_last=output_sun_pulse_times
INPUTS:
Model: pointer to s spinmodel structure
Time: A double precision scalar or array specifying the input times.
If the input is a scalar, all outputs will be scalars; otherwise,
all outputs are arrays having the same size as the input times.
OUTPUTS:
spinper: Optional keyword parameter to receive spin period values.
tlast: Optional keyword parameter to receive sun pulse time
immediately preceding each input time.
spincount: Optional keyword parameter to receive count of spins
since the start of the model.
spinphase: Optional keyword parameter to receive the spin phase
(ranging from 0.0 to 360.0 degrees) at each input time.
KEYWORDS:
/MODEL: Required input keyword argument, specifying a pointer to a
spinmodel structure.
/TIME: Required input keyword argument specifying a time or array of times.
/SPINPER: Optional keyword argument to receive spin period values.
/T_LAST: Optional keyword argument to receive sun pulse times
/SPINCOUNT: Optional keyword argument to receive spin counts
/SPINPHASE: Optional keyword argument to receive spin phase
PROCEDURE:
Find the spinmodel segment containing the input time.
Use b and c segment parameters to determine the spin period,
spin phase, and spin count at each input time
Invert phi(t) function to find sun pulse time immediately preceding
each input time.
EXAMPLE:
; Assume 'input_times' and 'input_spinphase' already exist as a
; IDL variables -- perhaps obtained from thm_load_state.
;
; Get a pointer to the spin model for probe A
modelptr=spinmodel_get_ptr('a')
; Calculate spin phase at each time from spin model
spinmodel_interp_t,model=modelptr,time=input_times,spinphase=output_spinphase
; Calculate spinphase differences between spin model and state
phi_diff=output_spinphase-input_spinphase
; Fix wraparounds
i=where(phi_diff GT 180.0D)
i2=where(phi_diff LT -180.0D)
phi_diff[i] = phi_diff[i] - 360.0D
phi_diff[i2] = phi_diff[i2] + 360.0D
Plot results
plot,input_times,phi_diff
(See themis/spin/spinmodel_interp_t.pro)
NAME:
SPINMODEL_TEST.PRO
PURPOSE:
Perform consistency checks on a spin model.
CATEGORY:
TDAS
CALLING SEQUENCE:
spinmodel_test,model_ptr
INPUTS:
model_ptr: A pointer to a spinmodel structure, obtained from the
spinmodel_common block or the spinmodel_get_ptr() function.
This input must be a scalar.
OUTPUTS:
Prints "PASS"/"FAIL" messages depending on outcome of tests.
KEYWORDS:
None.
PROCEDURE:
Validate model_ptr input argument.
Compare spin model capacity to actual number of segments.
Validate pointer to model segments.
Call segment_test on each model segment, check for any failures.
Examine boundaries of adjacent segments, making sure time and
spin_number endpoints are identical across each pair.
Exercise spinmodel_interp_n by retrieving modeled sun pulse
times by spin number.
Exercise spinmodel_interp_t by recalculating the spin count
and spin phase at each modeled sun pulse time.
Cross check results of spinmodel_interp_n and spinmodel_interp_t
to verify that the expected values are produced within
modest tolerances (allowable phase error .01 deg at each
modeled sun pulse time).
EXAMPLE:
model_ptr=spinmodel_get_ptr('a')
spinmodel_test,model_ptr
Written by: Jim Lewis (jwl@ssl.berkeley.edu)
Change Date: 2007-10-08
(See themis/spin/spinmodel_test.pro)
Procedure: THM_LOAD_SPIN
Purpose: Loads THEMIS spin model parameters, performs some post-processing
of data loaded from the SPIN CDFs, and stashes the resulting spin model
in a common block.
keywords:
probe = Probe name. The default is 'all', i.e., load all available probes.
This can be an array of strings, e.g., ['a', 'b'] or a
single string delimited by spaces, e.g., 'a b'
Flatsat data (probe 'f') is not returned unless explicitly
mentioned.
datatype = The type of data to be loaded, can be an array of strings
or single string separate by spaces. The default is 'all'
TRANGE= (Optional) Time range of interest (2 element array), if
this is not set, the default is to prompt the user. Note
that if the input time range is not a full day, a full
day's data is loaded
level = the level of the data, the default is 'l1', or level-1
data. A string (e.g., 'l2') or an integer can be used. 'all'
can be passed in also, to get all levels.
CDF_DATA: named variable in which to return cdf data structure: only works
for a single spacecraft and datafile name.
VARNAMES: names of variables to load from cdf: default is all.
/GET_SUPPORT_DATA: load support_data variables as well as data variables
into tplot variables.
/DOWNLOADONLY: download file but don't read it.
/valid_names, if set, then this routine will return the valid probe, datatype
and/or level options in named variables supplied as
arguments to the corresponding keywords.
files named varible for output of pathnames of local files.
/VERBOSE set to output some useful info
Example:
thm_load_spin,probe=['a','b']
Written by: Jim Lewis (jwl@ssl.berkeley.edu)
Change Date: 2007-10-08
(See themis/spin/thm_load_spin.pro)