Guide to Madagascar programs

sfwindow: Window a portion of a dataset.

sfwindow < in.rsf > out.rsf verb=n squeeze=y j#=(1,...) d#=(d1,d2,...) f#=(0,...) min#=(o1,o2,,...) n#=(0,...) max#=(o1+(n1-1)*d1,o2+(n1-1)*d2,,...)

float	d#=(d1,d2,...)		sampling in #-th dimension
largeint	f#=(0,...)		window start in #-th dimension
int	j#=(1,...)		jump in #-th dimension
float	max#=(o1+(n1-1)*d1,o2+(n1-1)*d2,,...)		maximum in #-th dimension
float	min#=(o1,o2,,...)		minimum in #-th dimension
largeint	n#=(0,...)		window size in #-th dimension
bool	squeeze=y	[y/n]	if y, squeeze dimensions equal to 1 to the end
bool	verb=n	[y/n]	Verbosity flag

sfwindow is used to window a portion of the dataset. Here is a quick example: Start by creating some data.

bash$ sfmath n1=5 n2=3 o1=1 o2=1 output="x1*x2" > test.rsf
bash$ < test.rsf sfdisfil
   0:             1            2            3            4            5
   5:             2            4            6            8           10
  10:             3            6            9           12           15

Now window the first two rows:

bash$ < test.rsf sfwindow n2=2 | sfdisfil
   0:             1            2            3            4            5
   5:             2            4            6            8           10

Window the first three columns:

bash$ < test.rsf sfwindow n1=3 | sfdisfil
   0:             1            2            3            2            4
   5:             6            3            6            9

Window the middle row:

bash$ < test.rsf sfwindow f2=1 n2=1 | sfdisfil
   0:             2            4            6            8           10

You can interpret the f# and n# parameters as meaning "skip that many rows/columns" and "select that many rows/columns" correspondingly. Window the middle point in the dataset:

bash$ < test.rsf sfwindow f1=2 n1=1 f2=1 n2=1 | sfdisfil
   0:             6

Window every other column:

bash$ < test.rsf sfwindow j1=2 | sfdisfil
   0:             1            3            5            2            6
   5:            10            3            9           15

Window every third column:

bash$ < test.rsf sfwindow j1=3 | sfdisfil
   0:             1            4            2            8            3
   5:            12

Alternatively, sfwindow can use the minimum and maximum parameters to select a window. In the following example, we are creating a dataset with sfspike and then windowing a portion of it between 1 and 2 seconds in time and sampled at 8 miliseconds.

bash$ sfspike n1=1000 n2=10 > spike.rsf         
bash$ sfin spike.rsf
spike.rsf:
    in="/var/tmp/spike.rsf@"
    esize=4 type=float form=native 
    n1=1000        d1=0.004       o1=0          label1="Time" unit1="s" 
    n2=10          d2=0.1         o2=0          label2="Distance" unit2="km" 
        10000 elements 40000 bytes
bash$ < spike.rsf sfwindow min1=1 max1=2 d1=0.008 > window.rsf
bash$ sfin window.rsfwindow.rsf:
    in="/var/tmp/window.rsf@"
    esize=4 type=float form=native 
    n1=126         d1=0.008       o1=1          label1="Time" unit1="s" 
    n2=10          d2=0.1         o2=0          label2="Distance" unit2="km" 
        1260 elements 5040 bytes

By default, sfwindow ``squeezes'' the hypercube dimensions that are equal to one toward the end of the dataset. Here is an example of taking a time slice:

bash$ < spike.rsf sfwindow n1=1 min1=1 > slice.rsf
bash$ sfin slice.rsf 
slice.rsf:
    in="/var/tmp/slice.rsf@"
    esize=4 type=float form=native 
    n1=10          d1=0.1         o1=0          label1="Distance" unit1="km" 
    n2=1           d2=0.004       o2=1          label2="Time" unit2="s" 
        10 elements 40 bytes

You can change this behavior by specifying squeeze=n.

bash$ < spike.rsf sfwindow n1=1 min1=1 squeeze=n > slice.rsf
bash$ sfin slice.rsf slice.rsf:
    in="/var/tmp/slice.rsf@"
    esize=4 type=float form=native 
    n1=1           d1=0.004       o1=1          label1="Time" unit1="s" 
    n2=10          d2=0.1         o2=0          label2="Distance" unit2="km" 
        10 elements 40 bytes

Guide to Madagascar programs