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#On the name of ALLAH and may the blessing and peace of Allah 
#be upon the Messenger of Allah Mohamed Salla Allahu Aliahi Wassalam.
#Author : Fouad Teniou
#Date : 10/07/10
#version :2.6

"""
maclaurin_ln is a function to compute ln(x) using maclaurin series
and the interval of convergence is -1 < x < +1
ln(y) = ln(1+x/1-x)= 2(x + x^3/3 + x^5/5 + x^7/7 ...........)
"""


def maclaurin_ln(value, k):
    """
    Compute maclaurin's series approximation for ln(value).
    """
    
    global first_value    
    first_value = 0.0
    
    #attempt to Approximate ln(x) for a given value    
    try:
        value_x = (value - 1)/float(value + 1)
        for item in xrange(1,k,2):
            next_value = value_x **item/item
            first_value += next_value
            
        return 2*(first_value)
    
    #Raise TypeError if input is not a number   
    except TypeError:
        print 'Please enter an integer or a float value'

if __name__ == "__main__":
    
    maclaurin_ln_1 = maclaurin_ln(2,100)
    print maclaurin_ln_1
    maclaurin_ln_2 = maclaurin_ln(5,100)
    print maclaurin_ln_2
    maclaurin_ln_3 = maclaurin_ln(777,10000)
    print maclaurin_ln_3
    print 
    for arg in xrange(7,28,10):
        print "ln(%s) = %s " %\
        (arg, maclaurin_ln(arg,10000))
###########################################################################

#"C: python \Maclaurin_ln
#0.69314718056
#1.60943791243
#6.65544035037

#ln(7) = 1.94591014906
#ln(17) = 2.83321334406
#ln(27) = 3.295836866

Diff to Previous Revision

--- revision 5 2010-07-15 10:59:15
+++ revision 6 2010-07-15 11:02:47
@@ -54,46 +54,3 @@
 #ln(7) = 1.94591014906
 #ln(17) = 2.83321334406
 #ln(27) = 3.295836866
-######################################################################################
-
-
-#On the name of ALLAH and may the blessing and peace of Allah 
-#be upon the Messenger of Allah Mohamed Salla Allahu Aliahi Wassalam.
-#Author : Fouad Teniou
-
-# ln(x) decimal version 
-
-
-from decimal import Decimal as D,Context, localcontext
-def maclaurin_ln(value, k):
-    """
-    Compute maclaurin's series approximation for ln(value).
-    """
-     
-    first_value = 0
-    
-    #attempt to Approximate ln(x) for a given value    
-    try:
-        value_x = (value - D("1.0"))/(value + D("1.0"))
-        for item in xrange(1,k,2):
-            next_value = value_x**item/item
-            first_value += next_value
-            
-        return 2*(first_value)
-    
-    #Raise TypeError if input is not a number   
-    except TypeError:
-        print 'Please enter an integer or a float value'
-
-if __name__ == "__main__":
-    with localcontext(Context(prec=67)):
-        for arg in xrange(7,28,10):
-            print "ln(%s) = %s " %\
-            (arg, maclaurin_ln(arg,D("10000")))
-    
-#######################################################################
-
-FT  "C:\Maclaurin_lndecimal1.py"
-ln(7) = 1.945910149055313305105352743443179729637084729581861188459390149937
-ln(17) = 2.833213344056216080249534617873126535588203012585744787297237737878
-ln(27) = 3.295836866004329074185735710767577113942471673468248355204083000896

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