Matrix Indexing and manipulations

I have 4 points with point ID A, B, C & D which is a 4 by 3 matrix (A_matrix), I want to manipulate it such that the resultant B_matrix is 6 by 6 matrix. Note, the B-matrix most follow the definition of point ID " From To " to enable further applications. Can somebody assist me, please.

A_Matrix

x y z

A 593898.8877 -4856214.546 4078710.706

B 594576.9223 -4855007.836 4080036.446

C 593997.0267 -4854862.499 4080291.279

D 593319.2704 -4855416.031 4079738.306

B_Matrix

From To X Y Z X Y Z

A B 593898.8877 -4856214.546 4078711 594576.9 -4855008 4080036

B C 594576.9223 -4855007.836 4080036 593997 -4854862 4080291

A C 593898.8877 -4856214.546 4078711 593997 -4854862 4080291

D C 593319.2704 -4855416.031 4079738 593997 -4854862 4080291

A C 593898.8877 -4856214.546 4078711 593997 -4854862 4080291

B D 594576.9223 -4855007.836 4080036 593319.3 -4855416 4079738

Answer 1

[Matt J]

[A_matrix([1 2 1 4 1 2],:) , A_matrix([2 3 3 3 3 4],:)]

[Abel Francis]

Thank you very much Mr. Matt J, your suggestion works perfectly well. But supposing I am to transform a large A_matrix of size m by 3 to B_matrix of size n by 6 how do I go about it. I mean can there be a more generalized solution to this. Thank you once more.

[Matt J]

You would have to explain the general rule by which the pairs of rows are selected. Why, for example, in the m=4 case does the pair {A,C} occur twice?

[Abel Francis]

OK sir. The pairs of rows in the output matrix, B_matrix, are based on direction of the vectors; From To as given with the points data earlier on. The pair {A C} should appear only once. After getting B_matrix,l would like to do something like this; n=length(B_matrix); dX=zeros(n,1);dY=zeros(n,1);dZ=zeros(n,1); for i=1:n dX(i)=B_matrix(i,end-2)-B_matrix(i,1); dY(i)=B_matrix(i,end-1)-B_matrix(i,2); dZ(i)=B_matrix(i,end)-B_matrix(i,3); end

Blvector=[dX dY DZ]; Thank you for assistance.

[Matt J]

The pair {A C} should appear only once.

But in your original post it appears twice.

There are also pairs that do not appear in your 4x3 example, like From=B, To=A. How do you decide which pairs do not appear?

[Abel Francis]

Hi Mr. Matt J. Am sorry for not given you clear direction as to the composition of the baseline component definition, " From To ". After careful study, I got to know that the pair {A C} or any other combination can appear once or more depending on the direction of pair sought. In fact pairing patterrn is determine by the layout of points. So there is no fix pattern for " From To ". The pupose of the paring is to enable me subsract " From" from " To ", that is, 'C- A', 'E- A', etc. to get vectors dX, dY & dZ. The data format below which contains new dataset is important because there are other functions that make use of it. My concern is that I have a large dataset consisting of 32 points with about 171 baselines to handle. So generalizing the process is neccessary. Thank you for your consideration.

A 402.35087 -4652995.30109 4349760.77753

B 8086.03178 -4642712.84739 4360439.08326

C 12046.58080 -4649394.08240 4353160.06450

D -3081.58310 -4643107.36920 4359531.12340

E -4919.33880 -4649361.21990 4352934.45480

F 1518.80120 -4648399.14540 4354116.691

A C

A E

B C

B D

D C

D E

F A

F C

F E

F D

F B

B F

A F

A B

[Matt J]

You're quite welcome.

[Abel Francis]

Hello Master Matt. I was able to solved the problem I posted some Months ago. The implementation and data format is as shown below. Kindly verify if it is correct. I have attached the function file, gpsblvec.m.

% ECEF GPS COORDINATE GEODETIC EQUIVALENT % STN x y z lon lat h % A 593898.8877 -4856214.546 4078710.706 9 14 16 12 45 17 227.216 % B 594576.9223 -4855007.836 4080036.446 9 52 00 12 40 12 225.375 % C 593997.0267 -4854862.499 4080291.279 9 44 18 12 15 47 224.833 % D 593319.2704 -4855416.031 4079738.306 9 11 26 12 44 10 226.99 % A B % B C % A C % D C % A C % B D

x=[593898.8877;594576.9223;593997.0267;593319.2704];

y=[-4856214.546;-4855007.836;-4854862.499;-4855416.031];

z=[4078710.706;4080036.446;4080291.279;4079738.306];

fromto={'A' 'B';'B' 'C';'A' 'C';'D' 'C';'A' 'C';'B' 'D'}; m=4;

          [dX,dY,dZ] =gpsblvec(fromto,x,y,z,m)

Answer 2

[Abel Francis]

Attached is the file Master Matt.