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Groupvel #30

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Groupvel #30

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803946b
added .DS_Stote to .gitignore
alanfbaird Feb 5, 2016
d57a98d
added MS_groupvels (copied from MS_Phasevels with added function rayvel
alanfbaird Feb 5, 2016
cae5a84
MS_groupvels should now output group velocities
alanfbaird Feb 5, 2016
349301c
updated phasevels to output eigenvectors and prop vector, used it in …
alanfbaird Mar 4, 2016
6270c98
fixed some bugs in MS_groupvels
alanfbaird Mar 10, 2016
e289626
tidied up indentation
alanfbaird Mar 11, 2016
a1eada4
added ref for groupvels and updated phasevel documentation
alanfbaird Mar 11, 2016
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1 change: 1 addition & 0 deletions .gitignore
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215 changes: 215 additions & 0 deletions msat/MS_groupvels.m
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% MS_GROUPVELS - Wave velocities in anisotropic media.
%
% // Part of MSAT - The Matlab Seismic Anisotropy Toolkit //
%
% Calculate the group velocity details for an elsticity matrix.
%
% [ VGP, VGS1, VGS2, ...] = MS_groupvels( C, rh, inc, azi )
%
% Usage:
% [ VGP, VGS1, VGS2, ...] = MS_groupvels( C, rh, inc, azi )
% Calculate group velocity vectors from elasticity matrix C (in GPa) and
% density rh (in kg/m^3) corresponding to a phase angle defined by
% an inclination and azimuth (both in degrees). Output
% details are given below.
%
% [ VGP, VGS1, VGS2, PE, S1E, S2E ] = MS_groupvels( C, rh, inc, azi )
% Additionally output P, S1 and S2-wave polarisations in vector
% form.
%
% [ VGP, VGS1, VGS2, PE, S1E, S2E, SNP, SNS1, SNS2 ] = MS_groupvels( C, rh, inc, azi )
% Additionally output P, S1 and S2 Slowness vectors
%
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any reference to add?

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also add
% see also: MS_phasevels

%
% Notes:
% This code is based on EMATRIX6 by D. Mainprice, recoded in
% MATLAB by Alan Baird.
%
% Reference: Mainprice D. (1990). An efficient
% FORTRAN program to calculate seismic anisotropy from
% the lattice preferred orientation of minerals.
% Computers & Gesosciences, vol16, pp385-393.
%
% See also: MS_PHASEVELS

% Copyright (c) 2016, Alan Baird
% All rights reserved.
%
% Redistribution and use in source and binary forms,
% with or without modification, are permitted provided
% that the following conditions are met:
%
% * Redistributions of source code must retain the
% above copyright notice, this list of conditions
% and the following disclaimer.
% * Redistributions in binary form must reproduce
% the above copyright notice, this list of conditions
% and the following disclaimer in the documentation
% and/or other materials provided with the distribution.
% * Neither the name of the University of Bristol nor the names
% of its contributors may be used to endorse or promote
% products derived from this software without specific
% prior written permission.
%
% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
% AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
% WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
% WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
% PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
% THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
% DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
% PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
% USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
% CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
% OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
% SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

function [ varargout ] = MS_groupvels(C,rh,inc,azi)

[~,~,vs1,vs2,vp,~,~,PE,S1E,S2E,XIS] = MS_phasevels(C,rh,inc,azi);

SNP = zeros(length(azi),3) ;
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Could you tidy up the indentation?

SNS1 = zeros(length(azi),3) ;
SNS2 = zeros(length(azi),3) ;
VGP = zeros(length(azi),3) ;
VGS1 = zeros(length(azi),3) ;
VGS2 = zeros(length(azi),3) ;




% ** start looping
for ipair = 1:length(inc)

% ** slowness vectors
SNP(ipair,:) = XIS(ipair,:)./vp(ipair);
SNS1(ipair,:) = XIS(ipair,:)./vs1(ipair);
SNS2(ipair,:) = XIS(ipair,:)./vs2(ipair);

% ** Group velocity vectors

VGP(ipair,:) = rayvel(C,SNP(ipair,:),rh./1e3);
VGS1(ipair,:) = rayvel(C,SNS1(ipair,:),rh./1e3);
VGS2(ipair,:) = rayvel(C,SNS2(ipair,:),rh./1e3);

end

switch nargout
case 3
varargout{1} = VGP ;
varargout{2} = VGS1 ;
varargout{3} = VGS2 ;


case 6
varargout{1} = VGP ;
varargout{2} = VGS1 ;
varargout{3} = VGS2 ;
varargout{4} = PE ;
varargout{5} = S1E ;
varargout{6} = S2E ;


case 9
varargout{1} = VGP ;
varargout{2} = VGS1 ;
varargout{3} = VGS2 ;
varargout{4} = PE ;
varargout{5} = S1E ;
varargout{6} = S2E ;
varargout{7} = SNP ;
varargout{8} = SNS1 ;
varargout{9} = SNS2 ;

otherwise
error('MS:GROUPVELS:BadOutputArgs','Requires 3, 6, or 9 output arguments.')
end



return
%=======================================================================================






function VG =rayvel(C,SN,rho)
% TO CALCULATE THE RAY-VELOCITY VECTOR CORRESPONDING TO A SLOWNESS VECTOR.
% Original fortran by David Mainprice as part of the EMATRIX code.
% Converted to Python by Alan Baird
%
% C: Stiffness tensor in Voigt Notation (6X6).
% SN: Slowness vector (3).
% rho: Density
%
% returns VG: Group velocity vector (3)

ijkl = [1,6,5; ...
6,2,4; ...
5,4,3] ;


gamma = [SN(1) 0.0 0.0 0.0 SN(3) SN(2) ; ...
0.0 SN(2) 0.0 SN(3) 0.0 SN(1) ; ...
0.0 0.0 SN(3) SN(2) SN(1) 0.0 ];

F = gamma * C * gamma'-eye(3).*rho;


% Signed cofactors of F[i,k]
CF = zeros(3,3);

CF(1,1)=F(2,2)*F(3,3)-F(2,3)^2;
CF(2,2)=F(1,1)*F(3,3)-F(1,3)^2;
CF(3,3)=F(1,1)*F(2,2)-F(1,2)^2;
CF(1,2)=F(2,3)*F(3,1)-F(2,1)*F(3,3);
CF(2,1)=CF(1,2);
CF(2,3)=F(3,1)*F(1,2)-F(3,2)*F(1,1);
CF(3,2)=CF(2,3);
CF(3,1)=F(1,2)*F(2,3)-F(1,3)*F(2,2);
CF(1,3)=CF(3,1);


% Derivatives of determinant elements
DF = zeros(3,3,3);
for i=1:3
for j=1:3
for k=1:3
DF(i,j,k)=0.0;
for l=1:3
DF(i,j,k) = DF(i,j,k) + (C(ijkl(i,j),ijkl(k,l))+ C(ijkl(k,j),ijkl(i,l)) ) * SN(l);
end
end
end
end

% Components of Gradient
DFD = zeros(3,1);
for k=1:3
DFD(k) = 0.0;
for i=1:3
for j=1:3
DFD(k)=DFD(k)+DF(i,j,k)*CF(i,j);
end
end
end

% Normalize to obtain group velocity
denom = 0.0;
VG = zeros(3,1);
for i=1:3
denom = denom+SN(i)*DFD(i);
end
for i=1:3
VG(i) = DFD(i)./denom;
end

return % function




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