@@ -10,38 +10,38 @@ Last updated |today|.
1010
1111Tool for unbiased peak extraction from atomic pair distribution functions.
1212
13- The diffpy.srmise package is an implementation of the `ParSCAPE algorithm
14- <https://dx.doi.org/10.1107/S2053273315005276> `_ for peak extraction from
15- atomic pair distribution functions (PDFs). It is designed to function even
16- when *a priori * knowledge of the physical sample is limited, utilizing the
17- Akaike Information Criterion (AIC) to estimate whether peaks are
18- statistically justified relative to alternate models. Three basic use cases
19- are anticipated for diffpy.srmise. The first is peak fitting a user-supplied
20- collections of peaks. The second is peak extraction from a PDF with no (or
21- only partial) user-supplied peaks. The third is an AIC-driven multimodeling
22- analysis where the output of multiple diffpy.srmise trials are ranked.
23-
24- The framework for peak extraction defines peak-like clusters within the data,
25- extracts a single peak within each cluster, and iteratively combines nearby
26- clusters while performing a recursive search on the residual to identify
27- occluded peaks. Eventually this results in a single global cluster
28- containing many peaks fit over all the data. Over- and underfitting are
29- discouraged by use of the AIC when adding or removing (during a pruning step)
30- peaks. Termination effects, which can lead to physically spurious peaks in
31- the PDF, are incorporated in the mathematical peak model and the pruning step
32- attempts to remove peaks which are fit better as termination ripples due to
33- another peak.
34-
35- Where possible, diffpy.srmise provides physically reasonable default values
36- for extraction parameters. However, the PDF baseline should be estimated by
37- the user before extraction, or by performing provisional peak extraction with
38- varying baseline parameters. The package defines a linear (crystalline)
39- baseline, arbitrary polynomial baseline, a spherical nanoparticle baseline,
40- and an arbitrary baseline interpolated from a list of user-supplied values.
41- In addition, PDFs with accurate experimentally-determined uncertainties are
42- necessary to provide the most reliable results, but historically such PDFs
43- are rare. In the absence of accurate uncertainties an ad hoc uncertainty
44- must be specified.
13+ The diffpy.srmise package is an implementation of the `ParSCAPE algorithm
14+ <https://dx.doi.org/10.1107/S2053273315005276> `_ for peak extraction from
15+ atomic pair distribution functions (PDFs). It is designed to function even
16+ when *a priori * knowledge of the physical sample is limited, utilizing the
17+ Akaike Information Criterion (AIC) to estimate whether peaks are
18+ statistically justified relative to alternate models. Three basic use cases
19+ are anticipated for diffpy.srmise. The first is peak fitting a user-supplied
20+ collections of peaks. The second is peak extraction from a PDF with no (or
21+ only partial) user-supplied peaks. The third is an AIC-driven multimodeling
22+ analysis where the output of multiple diffpy.srmise trials are ranked.
23+
24+ The framework for peak extraction defines peak-like clusters within the data,
25+ extracts a single peak within each cluster, and iteratively combines nearby
26+ clusters while performing a recursive search on the residual to identify
27+ occluded peaks. Eventually this results in a single global cluster
28+ containing many peaks fit over all the data. Over- and underfitting are
29+ discouraged by use of the AIC when adding or removing (during a pruning step)
30+ peaks. Termination effects, which can lead to physically spurious peaks in
31+ the PDF, are incorporated in the mathematical peak model and the pruning step
32+ attempts to remove peaks which are fit better as termination ripples due to
33+ another peak.
34+
35+ Where possible, diffpy.srmise provides physically reasonable default values
36+ for extraction parameters. However, the PDF baseline should be estimated by
37+ the user before extraction, or by performing provisional peak extraction with
38+ varying baseline parameters. The package defines a linear (crystalline)
39+ baseline, arbitrary polynomial baseline, a spherical nanoparticle baseline,
40+ and an arbitrary baseline interpolated from a list of user-supplied values.
41+ In addition, PDFs with accurate experimentally-determined uncertainties are
42+ necessary to provide the most reliable results, but historically such PDFs
43+ are rare. In the absence of accurate uncertainties an ad hoc uncertainty
44+ must be specified.
4545
4646
4747===================
@@ -81,7 +81,7 @@ Where next?
8181
8282 tutorial/index.rst
8383 extending.rst
84-
84+
8585======================================
8686API
8787======================================
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