Can one define a one dimensional image inline? - dm-script

Question

I would like to describe a very simple image (really a vector) of length 2, like (1,2) for the purpose of some linear algebra.
The following creates a two dimensional image with a y axis of length 1:
image a := [2,1]: {
{1, 2}
}
MatrixPrint(a)
This outputs
{
{1, 2}
}
How would I in a similar fashion output this instead?
{123,45}
Additionally, if I had image of arbitrary shape (a, b), how can I slice it to extract a one dimensional image at a value n, either along the x or y axes? (Extracting a line profile along one of the image axes)

Answer 1

In your example you do define a 2D image, so you get a 2D output. If the image really would be 1D, your output would be 1D, i.e.
image a := [2]: {123, 45}
MatrixPrint(a)
So your second question actually is the answer to your first: You need to do a 1D slice of the data, which you can do with the command slice1() as follows:
image a := [2,1]: {
{123, 45}
}
MatrixPrint( a.slice1(0,0,0,0,2,1) )
Note some peculiarities of the command:
The command always assume the input is 3D, so the first 3 parameters are the start-index triplet x/y/z even if it is just 2D or 1D data.
the 2nd triplet specifies the sampling of the slice. First the dimensions index (0=x) then the number of sampling steps (2) and then the stepsize (1)
Similar slice commands exist for 2D slices, 3D slices and nD Slices from nD data.
The matrixPrint command only outputs to the results window. There is no way to reroute this to some string. However, you can easily make yourself a method that would do that (albeit not very fast for big data):
string VectorPrint( image img, string FormatStr, number maxNum )
{
if ( !img.ImageIsValid() ) return "{invalid}"
if ( 1 != img.ImageGetNumDimensions() ) return "{not 1D}"
string out = "{ "
number nx = img.ImageGetDimensionSize(0)
if (( nx <= maxNum ) || ( maxNum <= 2) )
{
for( number i=0; i<min(nx,maxNum); i++)
out += Format( sum(img[0,i]), FormatStr ) + ", "
out = out.left( out.len() - 2 )
}
else
{
for( number i=0; i<maxNum-1; i++)
out += Format( sum(img[0,i]), FormatStr ) + ", "
out = out.left( out.len() - 2 ) + ", ... , "
out += Format( sum(img[0,nx-1]), FormatStr )
}
out += " }"
return out
}
image a := [10,4]: {
{1,2,3,4,5,6,7,8,9,10},
{123, 45, 12.3, -12, 55, 1.2, 9999, 89.100, 1e-10, 0},
{0,0,0,0,0,0,0,0,0,0},
{1,2,3,4,5,6,7,8,9,10}
}
// Slice 2D image to 1D image at n'th line
number n = 1
image line := a.slice1(0,n,0,0,a.ImageGetDimensionSize(0),1)
// Printout with given number format and a maximum number of entries
string fStr = "%3.1f"
number maxN = 3
Result( "\n "+VectorPrint( line, fStr, maxN ) )