Guide to Madagascar programs

sfspike: Generate simple data: spikes, boxes, planes, constants.

sfspike < in.rsf > spike.rsf mag= nsp=1 k#=[0,...] l#=[k1,k2,...] p#=[0,...] n#= o#=[0,0,...] d#=[0.004,0.1,0.1,...] label#=[Time,Distance,Distance,...] unit#=[s,km,km,...] title=

Spike positioning is given in samples and starts with 1.

float	d#=[0.004,0.1,0.1,...]		sampling on #-th axis
ints	k#=[0,...]		spike starting position [nsp]
ints	l#=[k1,k2,...]		spike ending position [nsp]
string	label#=[Time,Distance,Distance,...]		label on #-th axis
floats	mag=		spike magnitudes [nsp]
int	n#=		size of #-th axis
int	nsp=1		Number of spikes
float	o#=[0,0,...]		origin on #-th axis
floats	p#=[0,...]		spike inclination (in samples) [nsp]
string	title=		title for plots
string	unit#=[s,km,km,...]		unit on #-th axis

sfspike takes no input and generates an output with ``spikes''. It is an easy way to create data. Here is an example:

bash$ sfspike n1=5 n2=3 k1=4 k2=1 | sfdisfil
   0:             0            0            0            1            0
   5:             0            0            0            0            0
  10:             0            0            0            0            0

The spike location is specified by parameters k1=4 and k2=1. Note that the locations are numbered starting from 1. If one of the parameters is omitted or given the value of zero, the spike in the corresponding direction becomes a plane:

bash$ sfspike n1=5 n2=3 k1=4 | sfdisfil   
   0:             0            0            0            1            0
   5:             0            0            0            1            0
  10:             0            0            0            1            0

If no spike parameters are given, the whole dataset is filled with ones:

bash$ sfspike n1=5 n2=3 | sfdisfil
   0:             1            1            1            1            1
   5:             1            1            1            1            1
  10:             1            1            1            1            1

To create several spikes, use the nsp= parameter and give a comma-separated list of values to k#= arguments:

bash$ sfspike n1=5 n2=3 nsp=3 k1=1,3,4 k2=1,2,3 | sfdisfil
   0:             1            0            0            0            0
   5:             0            0            1            0            0
  10:             0            0            0            1            0

If the number of values in the list is smaller than nsp, the last value gets repeated, and the spikes add on top of each other, creating larger amplitudes:

bash$ sfspike n1=5 n2=3 nsp=3 k1=1,3 k2=1,2 | sfdisfil
   0:             1            0            0            0            0
   5:             0            0            2            0            0
  10:             0            0            0            0            0

The magnitude of the spikes can be controlled explicitly with the mag= parameter:

bash$ sfspike n1=5 n2=3 nsp=3 k1=1,3,4 k2=1,2,3 mag=1,4,2 | sfdisfil
   0:             1            0            0            0            0
   5:             0            0            4            0            0
  10:             0            0            0            2            0

You can create boxes instead of spikes by using l#= parameters:

bash$ sfspike n1=5 n2=3 k1=2 l1=4 k2=2 mag=8 | sfdisfil
   0:             0            0            0            0            0
   5:             0            8            8            8            0
  10:             0            0            0            0            0

In this case, k1=2 specifies the box start, and l1=4 specifies the box end.

Finally, multi-dimensional planes can be given an inclination by using p#= parameters:

bash$ sfspike n1=5 n2=3 k1=2 p2=1 | sfdisfil
   0:             0            1            0            0            0
   5:             0            0            1            0            0
  10:             0            0            0            1            0

When the inclination value is not integer, simple linear interpolation is used:

bash$ sfspike n1=5 n2=3 k1=2 p2=0.7 | sfdisfil
   0:             0            1            0            0            0
   5:             0          0.3          0.7            0            0
  10:             0            0          0.6          0.4            0

sfspike supplies default dimensions and labels to all axis:

bash$ sfspike n1=5 n2=3 n3=4 > spike.rsf
bash$ sfin spike.rsf
spike.rsf:
    in="/var/tmp/spike.rsf@"
    esize=4 type=float form=native 
    n1=5           d1=0.004       o1=0          label1="Time" unit1="s" 
    n2=3           d2=0.1         o2=0          label2="Distance" unit2="km" 
    n3=4           d3=0.1         o3=0          label3="Distance" unit3="km" 
	60 elements 240 bytes

As you can see, the first axis is assumed to be time, with sampling of $0.004$ seconds. All other axes are assumed to be distance, with sampling of $0.1$ kilometers. All these parameters can be changed on the command line.

bash$ sfspike n1=5 n2=3 n3=4 label3=Offset unit3=ft d3=20 > spike.rsf
bash$ sfin spike.rsf
spike.rsf:
    in="/var/tmp/spike.rsf@"
    esize=4 type=float form=native 
    n1=5           d1=0.004       o1=0          label1="Time" unit1="s" 
    n2=3           d2=0.1         o2=0          label2="Distance" unit2="km" 
    n3=4           d3=20          o3=0          label3="Offset" unit3="ft" 
	60 elements 240 bytes

Guide to Madagascar programs