Basic MATLAB

1
Basic MATLAB
2
Matlab

• Post-processer
• Graphics
• Analytical solution comparisons

3
Vectors

• gtgt a1 2 3 4
• a
• 1 2 3 4
• gtgt a'
• ans
• 1
• 2
• 3
• 4

4
Autofilling and addressing Vectors

• gt a10.23'
• a
• 1.0000
• 1.2000
• 1.4000
• 1.6000
• 1.8000
• 2.0000
• 2.2000
• 2.4000
• 2.6000
• 2.8000
• 3.0000
• gtgt a(23)
• ans

5
xy Plots

• gtgt x1 3 6 8 10
• gtgt y0 2 1 3 1
• gtgt plot(x,y)

6
Matrices

• gtgt b1 2 3 45 6 7 8
• b
• 1 2 3 4
• 5 6 7 8
• gtgt b'
• ans
• 1 5
• 2 6
• 3 7
• 4 8

7
Matrices

• gtgt b2.2ones(4,4)
• b
• 2.2000 2.2000 2.2000 2.2000
• 2.2000 2.2000 2.2000 2.2000
• 2.2000 2.2000 2.2000 2.2000
• 2.2000 2.2000 2.2000 2.2000

8
Reshape

• gtgt a19
• a
• 1 2 3 4 5 6 7 8
  9
• gtgt bsquarereshape(a,3,3)
• bsquare
• 1 4 7
• 2 5 8
• 3 6 9
• gtgt

9
Load and if

• a load(filename) (semicolon suppresses echo)
• if(1)
• else
• end

10
For

• for i 110
• end

11
Grad

• dhdx,dhdygradient(h)

12
BMP Output

• bsqrand(100,100)
• bmp1 output
• e(,,1)1-bsq r
• e(,,2)1-bsq g
• e(,,3)ones(100,100) b
• imwrite(e, 'junk.bmp','bmp')
• image(imread('junk.bmp'))
• axis('equal')

13
Contours

• h
• contour(h)
• C,Hcontour(h)
• Clabel(C,H)

14
Contours (load data, prepare matrix)

• rhoload('rho_frame0012_subs00.dat')
• p_vectorrho/3
• rows100
• columns20
• for j1columns
• j
• for i1rows
• p(i,j)p_vector(j(i-1)columns)
• Get rid of '0 pressure' solids that
  dominate pressure field
• if p(i,j)0
• p(i,j)NaN
• end
• end
• end

15
Contours

• C,Hcontour(p)
• clabel(C,H)
• axis equal

16
Quiver (vector plots)

• gtgt scale10
• gtgt drand(100,4)
• gtgt quiver(d(,1),d(,2),d(,3),d(,4),scale)

17
Quiver (and Quiver3)

• uv_vectorload('u_frame0012_subs00.dat')
• rows100
• columns20
• for j1columns
• j
• for i1rows
• u(i,j)uv_vector(j(i-1)20,1)
• v(i,j)uv_vector(j(i-1)20,2)
• end
• end
• hold on
• quiver(u,v)

18
Streamline

• Stream stream2(u,v,5,100)
• streamline(Stream)

19
Streamlines

• Stream stream2(u,v,120,100ones(20,1))
• streamline(Stream)
• (This is for streamlines starting at y 100 from
  x 1 to 20 along the x axis. Different
  geometries will require different starting
  points.)

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