1- '''
1+ """
22------------------------------------------------------------------------
33This module contains the functions for probability density functions of
44continuous PDF's.
88 GG_pdf()
99 GB2_pdf()
1010------------------------------------------------------------------------
11- '''
11+ """
1212# Import packages
1313import numpy as np
1414import scipy .special as spc
1515
1616
17- '''
17+ """
1818------------------------------------------------------------------------
1919 Functions
2020------------------------------------------------------------------------
21- '''
21+ """
2222
2323
2424def LN_pdf (xvals , mu , sigma ):
25- '''
25+ """
2626 --------------------------------------------------------------------
2727 This function gives the PDF of the lognormal distribution for xvals
2828 given mu and sigma
@@ -46,16 +46,19 @@ def LN_pdf(xvals, mu, sigma):
4646
4747 RETURNS: pdf_vals
4848 --------------------------------------------------------------------
49- '''
50- pdf_vals = np .float64 (((1 / (np .sqrt (2 * np .pi ) * sigma * xvals )) *
51- np .exp ((- 1.0 / 2.0 ) *
52- (((np .log (xvals ) - mu ) / sigma ) ** 2 ))))
49+ """
50+ pdf_vals = np .float64 (
51+ (
52+ (1 / (np .sqrt (2 * np .pi ) * sigma * xvals ))
53+ * np .exp ((- 1.0 / 2.0 ) * (((np .log (xvals ) - mu ) / sigma ) ** 2 ))
54+ )
55+ )
5356
5457 return pdf_vals
5558
5659
5760def GA_pdf (xvals , alpha , beta ):
58- '''
61+ """
5962 --------------------------------------------------------------------
6063 Returns the PDF values from the two-parameter gamma (GA)
6164 distribution. See McDonald and Xu (1995).
@@ -80,16 +83,18 @@ def GA_pdf(xvals, alpha, beta):
8083
8184 RETURNS: pdf_vals
8285 --------------------------------------------------------------------
83- '''
84- pdf_vals = \
85- np .float64 ((1 / ((beta ** alpha ) * spc .gamma (alpha ))) *
86- (xvals ** (alpha - 1 )) * np .exp (- xvals / beta ))
86+ """
87+ pdf_vals = np .float64 (
88+ (1 / ((beta ** alpha ) * spc .gamma (alpha )))
89+ * (xvals ** (alpha - 1 ))
90+ * np .exp (- xvals / beta )
91+ )
8792
8893 return pdf_vals
8994
9095
9196def GG_pdf (xvals , alpha , beta , mm ):
92- '''
97+ """
9398 --------------------------------------------------------------------
9499 Returns the PDF values from the three-parameter generalized gamma
95100 (GG) distribution. See McDonald and Xu (1995).
@@ -118,17 +123,18 @@ def GG_pdf(xvals, alpha, beta, mm):
118123
119124 RETURNS: pdf_vals
120125 --------------------------------------------------------------------
121- '''
122- pdf_vals = \
123- np .float64 ((mm / ((beta ** alpha ) * spc .gamma (alpha / mm ))) *
124- (xvals ** (alpha - 1 )) *
125- np .exp (- ((xvals / beta ) ** mm )))
126+ """
127+ pdf_vals = np .float64 (
128+ (mm / ((beta ** alpha ) * spc .gamma (alpha / mm )))
129+ * (xvals ** (alpha - 1 ))
130+ * np .exp (- ((xvals / beta ) ** mm ))
131+ )
126132
127133 return pdf_vals
128134
129135
130136def GB2_pdf (xvals , aa , bb , pp , qq ):
131- '''
137+ """
132138 --------------------------------------------------------------------
133139 Returns the PDF values from the four-parameter generalized beta 2
134140 (GB2) distribution. See McDonald and Xu (1995).
@@ -158,10 +164,14 @@ def GB2_pdf(xvals, aa, bb, pp, qq):
158164
159165 RETURNS: pdf_vals
160166 --------------------------------------------------------------------
161- '''
162- pdf_vals = \
163- np .float64 ((aa * (xvals ** (aa * pp - 1 ))) / ((bb ** (aa * pp )) *
164- spc .beta (pp , qq ) *
165- ((1 + ((xvals / bb ) ** aa )) ** (pp + qq ))))
167+ """
168+ pdf_vals = np .float64 (
169+ (aa * (xvals ** (aa * pp - 1 )))
170+ / (
171+ (bb ** (aa * pp ))
172+ * spc .beta (pp , qq )
173+ * ((1 + ((xvals / bb ) ** aa )) ** (pp + qq ))
174+ )
175+ )
166176
167177 return pdf_vals
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