310 lines
9.5 KiB
Mathematica
310 lines
9.5 KiB
Mathematica
![]() |
% [lamb_all,lamb,lamb_err,unit,eps,ierr,h,xx,ambd]=Nonpar(t,M,iop,Mmin)
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%
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% BASED ON MAGNITUDE SAMPLE DATA M DETERMINES THE ROUND-OFF INTERVAL LENGTH
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% OF THE MAGNITUDE DATA - eps, THE SMOOTHING FACTOR - h, CONSTRUCTS
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% THE BACKGROUND SAMPLE - xx AND CALCULATES THE WEIGHTING FACTORS - ambd
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% FOR A USE OF THE NONPARAMETRIC ADAPTATIVE KERNEL ESTIMATORS OF MAGNITUDE
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% DISTRIBUTION.
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%
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% !! THIS FUNCTION MUST BE EXECUTED AT START-UP OF THE UNBOUNDED
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% NON-PARAMETRIC HAZARD ESTIMATION MODE !!
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%
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% AUTHOR: S. Lasocki ver 2 01/2015 within IS-EPOS project.
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%
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% DESCRIPTION: The kernel estimator approach is a model-free alternative
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% to estimating the magnitude distribution functions. The smoothing factor
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% h, is estimated using the least-squares cross-validation for the Gaussian
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% kernel function. The final form of the kernel is the adaptive kernel.
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% In order to avoid repetitions, which cannot appear in a sample when the
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% kernel estimators are used, the magnitude sample data are randomized
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% within the magnitude round-off interval. The round-off interval length -
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% eps is the least non-zero difference between sample data or 0.1 is the
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% least difference if greater than 0.1. The randomization is done
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% assuming exponential distribution of m in [m0-eps/2, m0+eps/2], where m0
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% is the sample data point and eps is the length of roud-off inteval. The
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% shape parameter of the exponential distribution is estimated from the whole
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% data sample assuming the exponential distribution. The background sample
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% - xx comprises the randomized values of magnitude doubled symmetrically
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% with respect to the value Mmin-eps/2: length(xx)=2*length(M). Weigthing
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% factors row vector for the adaptive kernel is of the same size as xx.
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% See: the references below for a more comprehensive description.
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%
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% This is a beta version of the program. Further developments are foreseen.
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%
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% REFERENCES:
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%Silverman B.W. (1986) Density Estimation for Statistics and Data Analysis,
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% Chapman and Hall, London
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%Kijko A., Lasocki S., Graham G. (2001) Pure appl. geophys. 158, 1655-1665
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%Lasocki S., Orlecka-Sikora B. (2008) Tectonophysics 456, 28-37
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%
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% INPUT:
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% t - vector of earthquake occurrence times
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% M - vector of earthquake magnitudes (sample data)
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% iop - determines the used unit of time. iop=0 - 'day', iop=1 - 'month',
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% iop=2 - 'year'
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% Mmin - lower bound of the distribution - catalog completeness level
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%
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% OUTPUT
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% lamb_all - mean activity rate for all events
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% lamb - mean activity rate for events >= Mmin
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% lamb_err - error paramter on the number of events >=Mmin. lamb_err=0
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% for 50 or more events >=Mmin and the parameter estimation is
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% continued, lamb_err=1 otherwise, all output paramters except
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% lamb_all and lamb are set to zero and the function execution is
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% terminated.
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% unit - string with name of time unit used ('year' or 'month' or 'day').
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% eps - length of round-off interval of magnitudes.
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% ierr - h-convergence indicator. ierr=0 if the estimation procedure of
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% the optimal smoothing factor has converged (the zero of the h functional
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% has been found, ierr=1 when multiple zeros of h functional were
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% encountered - the largest h is accepted, ierr = 2 when h functional did
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% not zeroe - the approximate h value is taken.
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% h - kernel smoothing factor.
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% xx - the background sample for the nonparametric estimators of magnitude
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% distribution
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% ambd - the weigthing factors for the adaptive kernel
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%
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% LICENSE
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% This file is a part of the IS-EPOS e-PLATFORM.
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%
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% This is free software: you can redistribute it and/or modify it under
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% the terms of the GNU General Public License as published by the Free
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% Software Foundation, either version 3 of the License, or
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% (at your option) any later version.
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%
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% This program is distributed in the hope that it will be useful,
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% but WITHOUT ANY WARRANTY; without even the implied warranty of
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% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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% GNU General Public License for more details.
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%
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function [lamb_all,lamb,lamb_err,unit,eps,ierr,h,xx,ambd]=...
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Nonpar_O(t,M,iop,Mmin)
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if isempty(t) || numel(t)<3 isempty(M(M>=Mmin)) %K03OCT
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t=[1 2];M=[1 2]; end %K30SEP
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lamb_err=0;
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%%% %%%%%%%%%%%%%MICHAL
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xx=NaN;
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ambd=NaN;
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%%% %%%%%%%%%%%%%MICHAL
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n=length(M);
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t1=t(1);
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for i=1:n
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if M(i)>=Mmin; break; end
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t1=t(i+1);
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end
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t2=t(n);
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for i=n:1
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if M(i)>=Mmin; break; end
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t2=t(i-1);
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end
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nn=0;
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for i=1:n
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if M(i)>=Mmin
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nn=nn+1;
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end
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end
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% SL 03MAR2015 ----------------------------------
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[NM,unit]=time_diff(t(1),t(n),iop);
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lamb_all=n/NM;
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[NM,unit]=time_diff(t1,t2,iop);
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lamb=nn/NM;
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% SL 03MAR2015 ----------------------------------
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if nn<50
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eps=0;ierr=0;h=0;
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lamb_err=1;
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return;
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end
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eps=magn_accur(M);
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n=0;
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for i=1:length(M)
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if M(i)>=Mmin;
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n=n+1;
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x(n)=M(i);
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end
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end
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x=sort(x)';
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beta=1/(mean(x)-Mmin+eps/2);
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[xx]=korekta(x,Mmin,eps,beta);
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xx=sort(xx);
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clear x;
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xx = podwajanie(xx,Mmin-eps/2);
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[h,ierr]=hopt(xx);
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[ambd]=scaling(xx,h);
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% enai=dlmread('para.txt'); %for fixed xx,ambd to test in different platforms
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% [ambd]=enai(:,1);
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% xx=enai(:,2)';
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% [h,ierr]=hopt(xx);
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end
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function [NM,unit]=time_diff(t1,t2,iop) % SL 03MAR2015
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% TIME DIFFERENCE BETWEEEN t1,t2 EXPRESSED IN DAY, MONTH OR YEAR UNIT
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%
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% t1 - start time (in MATLAB numerical format)
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% t2 - end time (in MATLAB numerical format) t2>=t1
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% iop - determines the used unit of time. iop=0 - 'day', iop=1 - 'month',
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% iop=2 - 'year'
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%
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% NM - number of time units from t1 to t2
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% unit - string with name of time unit used ('year' or 'month' or 'day').
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if iop==0
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NM=(t2-t1);
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unit='day';
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elseif iop==1
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V1=datevec(t1);
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V2=datevec(t2);
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NM=V2(3)/eomday(V2(1),V2(2))+V2(2)+12-V1(2)-V1(3)/eomday(V1(1),V1(2))...
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+(V2(1)-V1(1)-1)*12;
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unit='month';
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else
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V1=datevec(t1);
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V2=datevec(t2);
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NM2=V2(3);
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if V2(2)>1
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for k=1:V2(2)-1
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NM2=NM2+eomday(V2(1),k);
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end
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end
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day2=365; if eomday(V2(1),2)==29; day2=366; end;
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NM2=NM2/day2;
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NM1=V1(3);
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if V1(2)>1
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for k=1:V1(2)-1
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NM1=NM1+eomday(V1(1),k);
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end
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end
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day1=365; if eomday(V1(1),2)==29; day1=366; end;
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NM1=(day1-NM1)/day1;
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NM=NM2+NM1+V2(1)-V1(1)-1;
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unit='year';
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end
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end
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function [m_corr]=korekta(m,Mmin,eps,beta)
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% RANDOMIZATION OF MAGNITUDE WITHIN THE ACCURACY INTERVAL
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%
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% m - input vector of magnitudes
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% Mmin - catalog completeness level
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% eps - accuracy of magnitude
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% beta - the parameter of the unbounded exponential distribution
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%
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% m_corr - vector of randomized magnitudes
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%
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F1=1-exp(-beta*(m-Mmin-0.5*eps));
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F2=1-exp(-beta*(m-Mmin+0.5*eps));
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u=rand(size(m));
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w=u.*(F2-F1)+F1;
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m_corr=Mmin-log(1-w)./beta;
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end
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function x2 = podwajanie(x,x0)
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% DOUBLES THE SAMPLE
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% If the sample x(i) is is truncated from the left hand side and belongs
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% to the interval [x0,inf) or it is truncated from the right hand side and
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% belongs to the interval (-inf,x0]
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% then the doubled sample is [-x(i)+2x0,x(i)]
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% x - is the column data vector
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% x2 - is the column vector of data doubled and sorted in the ascending
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% order
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x2=[-x+2*x0
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x];
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x2=sort(x2);
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end
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function [h,ierr]=hopt(x)
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%Estimation of the optimal smoothing factor by means of the least squares
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%method
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% x - column data vector
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% The result is an optimal smoothing factor
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% ierr=0 - convergence, ierr=1 - multiple h, ierr=2 - approximate h is used
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% The function calls the procedure FZERO for the function 'funct'
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% NEW VERSION 2 - without a square matrix. Also equipped with extra zeros
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% search
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% MODIFIED JUNE 2014
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ierr=0;
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n=length(x);
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x=sort(x);
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interval=[0.000001 2*std(x)/n^0.2];
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x1=funct(interval(1),x);
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x2=funct(interval(2),x);
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if x1*x2<0
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fun = @(t) funct(t,x); % FOR OCTAVE
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x0 =interval; % FOR OCTAVE
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[hh(1),fval,exitflag] = fzero(fun,x0); % FOR OCTAVE
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% Extra zeros search
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jj=1;
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for kk=2:7
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interval(1)=1.1*hh(jj);
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interval(2)=interval(1)+(kk-1)*hh(jj);
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x1=funct(interval(1),x);
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x2=funct(interval(2),x);
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if x1*x2<0
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jj=jj+1;
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fun = @(t) funct(t,x); % FOR OCTAVE
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x0 =interval; % FOR OCTAVE
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[hh(jj),fval,exitflag] = fzero(fun,x0); % FOR OCTAVE
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end
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end
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if jj>1;ierr=1;end
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h=max(hh);
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if exitflag==1;return;end
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end
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h=0.891836*(mean(x)-x(1))/(n^0.2);
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ierr=2;
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end
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function [fct]=funct(t,x)
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p2=1.41421356;
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n=length(x);
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yy=zeros(size(x));
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for i=1:n,
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xij=(x-x(i)).^2/t^2;
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y=exp(-xij/4).*((xij/2-1)/p2)-2*exp(-xij/2).*(xij-1);
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yy(i)=sum(y);
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end;
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fct=sum(yy)-2*n;
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clear xij y yy;
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end
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function [ambd]=scaling(x,h)
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% EVALUATES A VECTOR OF SCALING FACTORS FOR THE NONPARAMETRIC ADAPTATIVE
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% ESTIMATION
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% x - the n dimensional column vector of data values sorted in the ascending
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% order
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% h - the optimal smoothing factor
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% ambd - the resultant n dimensional row vector of local scaling factors
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n=length(x);
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c=sqrt(2*pi);
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gau=zeros(1,n);
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for i=1:n,
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gau(i)=sum(exp(-0.5*((x(i)-x)/h).^2))/c/n/h;
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end
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g=exp(mean(log(gau)));
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ambd=sqrt(g./gau);
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end
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function [eps]=magn_accur(M)
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x=sort(M);
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d=x(2:length(x))-x(1:length(x)-1);
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eps=min(d(d>0));
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if eps>0.1; eps=0.1;end
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end
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