ProgrameR

Outer product of two vectors in Fortran

emeryyi — Sat, 22 May 2010 05:49:03 +0000

Unfortunately, no outer product intrinsic function available in Fortran. Outer product return a matrix from two user-provided vector a and b,

where

we have to implement our own function by

spread(a(1:n),dim=2,ncopies=n)*spread(b(1:n),dim=1,ncopies= p))

Here is some more detail about spread() function

SPREAD(SOURCE, DIM, NCOPIES)
! A is the array (/ -4.7, 6.1, 0.3 /)
       RES = SPREAD( A, DIM = 1, NCOPIES = 3 )
! The result is   | -4.7 6.1 0.3 |
!                 | -4.7 6.1 0.3 |
!                 | -4.7 6.1 0.3 |
! DIM=1 extends each column.  Each element in RES(:,1)
! becomes a copy of A(1), each element in RES(:,2) becomes
! a copy of A(2), and so on.
       RES = SPREAD( A, DIM = 2, NCOPIES = 3 )
! The result is   | -4.7 -4.7 -4.7 |
!                 |  6.1  6.1  6.1 |
!                 |  0.3  0.3  0.3 |
! DIM=2 extends each row.  Each element in RES(1,:)
! becomes a copy of A(1), each element in RES(2,:)
! becomes a copy of A(2), and so on.

Fortran Intrinsic Function for Lasso thresholding rule

emeryyi — Sat, 22 May 2010 04:59:24 +0000

In Lasso solution, the thresholding rule is

Which can be achieved in Fortran by

sign(dim(abs(a),b),a)

as easy as original function.

DIM(X, Y)

If X > Y, the value of the result is X – Y.
If X <= Y, the value of the result is zero.

SIGN(A, B)

The result is sgn*|A|, where:

sgn = -1, if either of the following is true:
1. B < 0
2. B is a REAL(4) or REAL(8) number with a value of negative 0, and you have specified the -qxlf90=signedzero option
sgn = 1, otherwise.

Indenting lines in gedit under Linux 10.04 lucid-lynx

emeryyi — Fri, 21 May 2010 06:59:31 +0000

In Linux 10.04 gedit lines indent plugin no longer exists, indention shortcuts now are replace by shortcut “Tab” and “shift+Tab” instead. No extra plugin is needed anymore.

Enable Aero Snap effect under Metacity in Linux

emeryyi — Fri, 21 May 2010 02:57:46 +0000

Waffleshop’s blog http://www.thewaffleshop.net/2010/03/08/aero-snap-effect-for-metacity/ gives some terminal command which enables Linux to have Aero snap feature like windows 7. This is much faster and resource efficient than its counterpart run under Compiz. You must have Metacity and wmctrl installed. To use it shortcut is WIN+<- and WIN+->

Snap Left:

1. gconftool-2 −type string –set /apps/metacity/global_keybindings/run_command_1 “Left”

2. gconftool-2 –type string –set /apps/metacity/keybinding_commands/command_1 “wmctrl -r :ACTIVE: -e 0,0,0,`xwininfo -root | grep Width | awk ‘{ print (($2/2)-6)}’`,`xwininfo -root | grep Height | awk ‘{ print $2 }’`”

Snap right:

1. gconftool-2 –type string –set /apps/metacity/global_keybindings/run_command_2 “Right”

2. gconftool-2 –type string –set /apps/metacity/keybinding_commands/command_2 “wmctrl -r :ACTIVE: -e 0,`xwininfo -root | grep Width | awk ‘{ print (($2/2)+5) “,0,” (($2/2)-6) }’`,`xwininfo -root | grep Height | awk ‘{ print $2 }’`”

Maximize:

1. gconftool-2 –type string –set /apps/metacity/window_keybindings/toggle_maximized “Up”