PsiLAB Help Manual Page

Section: Basic Matrix functions

Name: matrix_window

Extract a window from an already existing matrix.
This function extracts a window (sub range) of the matrix a and returns a new matrix b, but both matrices share the same data space. Therefore, changes in the window matrix b is visible to matrix a, and vice versa.

[ b:('a,'b,'c) Matrix.t ] = matrix_window
a:('a,'b,'c) Matrix.t
range: (int*int) list

The range list consists of int pair tuples for the window start and end indeces. With the (--) operator, the full dimension of the source matrix is preserved. All dimensions must be specified.
Warning:
Not all PsiLAB functions can handle matrix windows. Therefore, this function is intended for experts only.

Example: 
[] let f = fmatrix ~dim:[500;300] ~rand:[10.0] () ;; 
val f : (float, '_a, '_b) Matrix.t = <abstr> 
[] let fw = matrix_window f [(--);(10,20)] ;; 
val fw : (float, '_a, '_b) Matrix.t = <abstr> 
[] f.{1,10} 
- : float = 1.26877334984 
[] fw.{1,1} 
- : float = 1.26877334984

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