FINDRFC Finds indices to rainflow cycles of a sequence of TP. CALL: RFC_ind = findrfc(TP,h); TP = vector of turningpoints (NB! Only values, not sampled times) RFC_ind = indices to the rainflow cycles of the original sequence TP. h = a threshold, must be larger than zero. if h>0, then all rainflow cycles with height smaller than h are removed. This function is not implemented as a matlab function; instead, a mex file (originally written in C) is utilized. Example: x = load('sea.dat'); tp = dat2tp(x); ind = findrfc(tp(:,2),0.3); waveplot(x,tp(ind,:),1,1) See also tp2rfc, dat2tp.

- error

Display message and abort function. |

- dat2tp

Extracts turning points from data, |

001 function ind=findrfc(tp,h) 002 %FINDRFC Finds indices to rainflow cycles of a sequence of TP. 003 % 004 % CALL: RFC_ind = findrfc(TP,h); 005 % 006 % TP = vector of turningpoints (NB! Only values, not sampled times) 007 % 008 % RFC_ind = indices to the rainflow cycles of the 009 % original sequence TP. 010 % 011 % h = a threshold, must be larger than zero. 012 % if h>0, then all rainflow cycles with height 013 % smaller than h are removed. 014 % 015 % This function is not implemented as a matlab function; instead, a 016 % mex file (originally written in C) is utilized. 017 % 018 % Example: 019 % x = load('sea.dat'); 020 % tp = dat2tp(x); 021 % ind = findrfc(tp(:,2),0.3); 022 % waveplot(x,tp(ind,:),1,1) 023 % 024 % See also tp2rfc, dat2tp. 025 026 % This is a modified version of rfcfilt (found in WAT), which is about 20 027 % to 30 times faster than rfcfilt (on a PentiumII 233 MHz 028 % with 32 MB ram and Matlab 5.0 under Linux). The reason is 029 % that this version does not save TP to disk. Instead it passes 030 % the arguments directly to the executeable file. 031 % However, this solution requires different input and returns 032 % indices to the rfc instead of the rfc itself. 033 % It also ignores the first turningpoint if that is a maximum and 034 % starts on the first minimum when finding the sequence of rfc. 035 036 % Tested on Matlab 6.1,6.0, 5.2 037 % History: 038 % revised pab 10.08.2003 039 % - fixed a bug in the example 040 % Revised by pab 24.07.1999 041 042 043 ind=[]; 044 disp('FINDRFC is not implemented as a m-function') 045 disp(' compile the mexfile findrfc.c before you try again.') 046 error('findrfc error') 047 return

Mathematical Statistics

Centre for Mathematical Sciences

Lund University with Lund Institute of Technology

Comments or corrections to the WAFO group

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