TP2ARFC Calculates asymmetric rainflow cycles from turning points. CALL: [ARFC,ARFC1,res] = tp2arfc(tp,def,ARFC0,res0); ARFC = tp2arfc(tp); Output: ARFC = Asymetric RFC (residual included). [N,2]/[N,4] ARFC1 = Asymetric RFC (without resudual). [N1,2]/[N1,4] res = Residual. [nres,1]/[nres,2] Input: tp = Turning points. [T,1]/[T,2] def = Choice of definition of rainflow cycles [struct array] def.res = Treatment of residual. 'up': Count min-to-Max cycles, (default) gives correct number of upcrossings. 'down': Count Max-to-min cycles, gives correct number of downcrossings. 'CS': Cloormann/Seeger method, gives all closed hysterisis loops. This method is identical to the French AFNOR recommendation, and the ASTM standard (variant called simplified version). def.time = 0: Don't store time of max and min. (default) 1: Store the time when the maxima and minima occured. ARFC0 = Asymetric RFC (without resudual). [N0,2]/[N0,4] res0 = Residual. [nres0,1]/[nres0,2] Calculates the asymmetric rainflow cycles (ARFC) for the sequence of turning points, by using the so-called 4-point algorithm. It is possible to split the signal into smaller parts, and calculate ARFC part by part. It can be especially useful for long signals. We count the first part and for the second part we continue counting from previously counted 'ARFC0' with residual 'res0': [ARFC1,ARFC0,res0] = tp2arfc(tp(1:1000,:)); % Firts 1000 points [ARFC2] = tp2arfc(tp(1001:end,:),[],ARFC0,res0); % Point 1001 to end This shall give the same result as (i.e. ARFC=ARFC2) [ARFC] = tp2arfc(tp); % Calculate all at once sum(ARFC~=ARFC2) % Shall return [0 0] This routine doesn't use MEX, Fortran or C codes, only matlab code. Example: x = load('sea.dat'); tp=dat2tp(x); ARFC=tp2arfc(tp); % Default (min-to-Max cycles in residual) ccplot(ARFC) See also tp2arfc4p, findrfc, dtp2arfm, tp2rfc, tp2mm, dat2tp, rfcfilt

- res2arfc
- tp2arfc4p
- error
- ischar
- isfield
- isnumeric
- isstruct

Calculates asymmetric rainflow cycles for a residual. | |

Calculates asymmetric rainflow cycles from turning points (4-point). | |

Display message and abort function. | |

True for character array (string). | |

True if field is in structure array. | |

True for numeric arrays. | |

True for structures. |

- test_cycles
- tp2rfc

Quick test of the routines in module 'cycles' | |

Finds the rainflow cycles from the sequence of turning points. |

001 function [ARFC,ARFC1,res,def] = tp2arfc(x,def,ARFC0,res0) 002 %TP2ARFC Calculates asymmetric rainflow cycles from turning points. 003 % 004 % CALL: [ARFC,ARFC1,res] = tp2arfc(tp,def,ARFC0,res0); 005 % ARFC = tp2arfc(tp); 006 % 007 % Output: 008 % ARFC = Asymetric RFC (residual included). [N,2]/[N,4] 009 % ARFC1 = Asymetric RFC (without resudual). [N1,2]/[N1,4] 010 % res = Residual. [nres,1]/[nres,2] 011 % 012 % Input: 013 % tp = Turning points. [T,1]/[T,2] 014 % def = Choice of definition of rainflow cycles [struct array] 015 % def.res = Treatment of residual. 016 % 'up': Count min-to-Max cycles, (default) 017 % gives correct number of upcrossings. 018 % 'down': Count Max-to-min cycles, 019 % gives correct number of downcrossings. 020 % 'CS': Cloormann/Seeger method, 021 % gives all closed hysterisis loops. 022 % This method is identical to the French AFNOR recommendation, 023 % and the ASTM standard (variant called simplified version). 024 % def.time = 0: Don't store time of max and min. (default) 025 % 1: Store the time when the maxima and minima occured. 026 % ARFC0 = Asymetric RFC (without resudual). [N0,2]/[N0,4] 027 % res0 = Residual. [nres0,1]/[nres0,2] 028 % 029 % Calculates the asymmetric rainflow cycles (ARFC) for the sequence of 030 % turning points, by using the so-called 4-point algorithm. 031 % 032 % It is possible to split the signal into smaller parts, and calculate 033 % ARFC part by part. It can be especially useful for long signals. 034 % We count the first part and for the second part we continue counting 035 % from previously counted 'ARFC0' with residual 'res0': 036 % [ARFC1,ARFC0,res0] = tp2arfc(tp(1:1000,:)); % Firts 1000 points 037 % [ARFC2] = tp2arfc(tp(1001:end,:),[],ARFC0,res0); % Point 1001 to end 038 % This shall give the same result as (i.e. ARFC=ARFC2) 039 % [ARFC] = tp2arfc(tp); % Calculate all at once 040 % sum(ARFC~=ARFC2) % Shall return [0 0] 041 % 042 % This routine doesn't use MEX, Fortran or C codes, only matlab code. 043 % 044 % Example: 045 % x = load('sea.dat'); tp=dat2tp(x); 046 % ARFC=tp2arfc(tp); % Default (min-to-Max cycles in residual) 047 % ccplot(ARFC) 048 % 049 % See also tp2arfc4p, findrfc, dtp2arfm, tp2rfc, tp2mm, dat2tp, rfcfilt 050 051 % Tested on Matlab 5.3 052 % 053 % History: 054 % Revised by PJ 06-Jul-2005 055 % Fixed error with def & mod to avoid warning i R14SP2. 056 % Revised by PJ 26-Jul-2000 057 % New format of def. 058 % Revised by PJ 12-Jul-2000 059 % Now calls 'tp2arfc4p' to calculate ARFC0 and res. 060 % Input 'def_res'. 061 % Now supports AFNOR and ASTM standards for rainflow counting. 062 % Revised by PJ 18-May-2000 063 % updated help text. 064 % Revised by PJ 09-Jan-2000 065 % updated for WAFO 066 % Created by PJ (Pär Johannesson) 1999 067 068 % Check input arguments 069 ni = nargin; 070 no = nargout; 071 error(nargchk(1,4,ni)); 072 073 [T,nn] = size(x); 074 075 if ni<2, def = []; end 076 if ni<3, ARFC0 = []; end 077 if ni<4, res0 = []; end 078 079 def0=def; 080 if ~isempty(def) 081 if isnumeric(def) 082 def=[]; def.time = def0; 083 elseif ischar(def) 084 def=[]; def.res = def0; 085 elseif ~isstruct(def) 086 def=[]; 087 end 088 end 089 090 % Set default values 091 if ~isfield(def,'res') 092 def.res = 'up'; 093 end 094 if ~isfield(def,'time') 095 def.time = 0; 096 end 097 098 % Calculate ARFC0 and res 099 if def.time == 0 100 [ARFC,res] = tp2arfc4p(x(:,1:nn),res0,def.time); 101 else 102 if nn==1 103 [ARFC,res] = tp2arfc4p([(1:T)' x(:)],res0,def.time); 104 else 105 [ARFC,res] = tp2arfc4p(x,res0,def.time); 106 end 107 end 108 109 % Add previously counted cycles (if any) 110 if ~isempty(ARFC0) 111 ARFC = [ARFC0; ARFC]; 112 end 113 114 % Rainflow cycles without residual 115 if no>=2, ARFC1=ARFC; end 116 117 % Rainflow cycles plus cycles in residual 118 % ARFC = ARFC + 'cycles in res' 119 ARFC_res = res2arfc(res,def.res,def.time); % Treat residual 120 ARFC = [ARFC; ARFC_res]; 121 122 123

Mathematical Statistics

Centre for Mathematical Sciences

Lund University with Lund Institute of Technology

Comments or corrections to the WAFO group

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