[ncl-talk] sparse_matrix_mult

[Mark.Collier at csiro.au]

Hi,

I've been testing out some features/applications of sparse_matrix_mult and curious why the example doesn't replicate documentation, it could be that the documentation is out of date.



If I run example 1 from https://www.ncl.ucar.edu/Document/Functions/Built-in/sparse_matrix_mult.shtml


I get:



     bash-4.1$ ncl test_sparse.ncl 
 Copyright (C) 1995-2017 - All Rights Reserved
 University Corporation for Atmospheric Research
 NCAR Command Language Version 6.4.0
 The use of this software is governed by a License Agreement.
 See http://www.ncl.ucar.edu/ for more details.
  
   3.   6.   9.
  16.  20.  24.
  91. 104. 117.
***************
 

Variable: y
Type: float
Total Size: 48 bytes
            12 values
Number of Dimensions: 2
Dimensions and sizes:	[4] x [3]
Coordinates: 
Number Of Attributes: 1
  _FillValue :	9.96921e+36
(0,0)	 3
(0,1)	 6
(0,2)	 9
(1,0)	16
(1,1)	20
(1,2)	24
(2,0)	91
(2,1)	104
(2,2)	117
(3,0)	9.96921e+36
(3,1)	9.96921e+36
(3,2)	9.96921e+36
bash-4.1$ ncl -V
6.4.0
bash-4.1$ uname -a
Linux raijin1 3.10.0-693.5.2.el6.x86_64 #1 SMP Tue Oct 24 10:37:43 AEDT 2017 x86_64 x86_64 x86_64 GNU/Linux​

I have been using this function in relation to ESMF regridding, the regridding seems to be working using this call but I am porting the weights application to a python based approach and need to understand exactly what the matrix multiplication is doing.

Thanks for any advice
Mark.