Hi Monks,

My script generates a tons of histograms like this: http://kepfeltoltes.hu/130518/pAKT-tAKT_www.kepfeltoltes.hu_.png

As you can see there are two lognormal distribution on top of each other and I need the parameters of those distribution. To get that, I was trying to use Algorithm::CurveFit function, but the the Math::Symbolic package falis to parse my equation. (That I got from the wikipedia page: http://en.wikipedia.org/wiki/Log-normal_distribution#Probability_density_function)

I think I am making some mistakes when I phrasing the equation (I was trying the single lognormal first).

my $equation = '(exp(-1 * (log(x) - m)**2 / (2 * r ** 2)))/(x * r * 2.
+5066)';
# x - independent variable
# m - mean
# r - standard dev.

[download]

Here is a sample dataset:

0.0643566964735115    1
0.078213413896854    2
0.0862233698701667    2
0.0950536377503222    5
0.104788226940961    12
0.115519750377919    35
0.127350305630187    52
0.140392446235774    116
0.154770252513572    160
0.17062051203871    187
0.188094021012202    250
0.207357018905863    240
0.228592770031414    258
0.252003307080518    252
0.277811353223423    251
0.306262441052688    246
0.337627248531191    197
0.372204174168167    182
0.410322175922981    184
0.4523439008454    167
0.498669135227145    130
0.549738608088756    159
0.606038184187406    130
0.668103486437085    102
0.736524991717946    123
0.811953648555319    118
0.895107070113873    114
0.986776361425825    111
1.0878336458061    111
1.19924036205923    102
1.32205641141595    76
1.4574502412217    98
1.60670996131109    81
1.7712555988274    84
1.95265260807701    68
2.15262676394876    47
2.37308058059129    42
2.61611141155243    45
2.88403140358156    29
3.17938949393169    33
3.50499566043902    19
3.86394765509039    19
4.25966047541651    10
4.69589885409594    8
5.17681307586923    7
5.70697846251846    3
6.29143890156414    6
7.64605614922042    2
8.42910051556786    1

[download]

Was there some error with the equation? Should I use other package to do it? What would be the best way to go? I really need wisdom here! :) Thanks for your help!

Daniel

In reply to fitting double lognormal distribution on a dataset by sdani

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