Matlab functions that that I used

1. unique
2. intersect
3. load: load the mat file into the workspace.
4. ind2sub: Subscripts from linear index
5. matlab-remove-all-unwatned-elements-in
6. NaN: The IEEE floating point format used by most modern computers supports values that are "not a number". These values are called NaNs. "Not a number" values result from certain operations which have no meaningful numeric result, such as zero divided by zero or infinity divided by infinity.
7. cond: Condition number with respect to inversion
8. graythresh: Global image threshold using Otsu's method (In my experiment, otsu algorithm gave me the same image as produced by the manual trial and error. :))
9. bar: Plotting bar chart.
10. line: plotting a sequence of points by connecting two consecutive of them by a straight line.
11. floor: rounding the floating point number into an integer.
12. colfilt: Performing sliding neighborhood and distinct block operations columnwise, when possible, can reduce the execution time required to process an image.
13. nlfilter: Non-linear filter. Filter that uses mean, median, std. dev, non-max suppression etc.
14. bitwise OR or "|":   A | B performs a logical OR of arrays A and B and returns an array containing elements set to either logical 1 (TRUE) or logical 0 (FALSE). An element of the output array is set to 1 if either input array contains a non-zero element at that same array location. Otherwise, that element is set to 0. A and B must have the same dimensions unless one is a scalar. C = OR(A,B) is called for the syntax 'A | B' when A or B is an object. Application when did the A2 = W2' | W2; to construct the adjacency matrix of super-pixels.
15. genpath:  GENPATH Generate recursive toolbox path.
        P = GENPATH returns a new path string by adding all the subdirectories
        of MATLABROOT/toolbox, including empty subdirectories. restoredefaultpath;
    addpath(genpath('.')); 
16. csvread: reads comma separated data. Data in the input file needs to be separated by comma.
17. scatter: plots data in scattered manner.
18. patch: draws a polygonal shape specified by coordinate of some points. 
19. strfind: strfind(y,'xc') returns 1 if exist; and [] if doesn't. 
20. save:  save('/tmp/train.mat', 'B');
    Warning: Variable 'B' cannot be saved to a MAT-file whose version is older than 7.3. To save this variable, use the -v7.3 switch.
    >> save('/tmp/train.mat', 'B', '-v7.3');  // the variable is more than 2GB so -v7.3 options were required for that.
21. cat: cat(3,a,b,c) concatenate a,b,c along the third dimension. 
22. permute(imread(filename),[2 1]);  // transforming a WxH into HxW image
23.