FFT

FFT in IDL vs Fortran

http://www.ssec.wisc.edu/~paulv/fft/fft_comparison.html

Misc find / ls / linux cmds

find path -type d -ls  : lists all directories in given path

Visit

Volume rendering :

Steps :

1. Open - > load variable
2. Add volume -> rho
3.  plotatts - > volume -> splatting
4. set Tranparency : plotatts -> 1D transfer function
The grey bar denotes colors that are plotted. Removing grey area means those colors WILL NOT be shown in the 3-d rendering
5. choose color scale. hot desaturated is good.
6. Raycasting (composting) 600 points look ok


Make 3D vector field stream lines:

First create a vector vtk file with 3 components. Use Write_vtk,qx,qy,qz IDl routine

> Load vecfield

> Pseudocolor-->operators-->IntegralCurve-->vecfield

Click on Integral Curve to open operator attributes. Adjust as per choice.
Common adjusts:
1. source type: circle
2. Choose circle radius etc
3. Integration direction: Both for up and downsteam both.
4. Tab: Appearance--> Data Value: absolute time for checking progress or speed for magnitude

Click on pseudocolor for plot attributes
1. --> Geometry --> Line type: Tubes