[Octave-bug-tracker] [bug #30121] interpn.m & __interpn_lin__.m problem

[Philip Nienhuis]

URL:
  <http://savannah.gnu.org/bugs/?30121>

                 Summary: interpn.m & __interpn_lin__.m problem
                 Project: GNU Octave
            Submitted by: philipnienhuis
            Submitted on: Sat 12 Jun 2010 10:21:22 PM GMT
                Category: Libraries
                Severity: 3 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Philip Nienhuis
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.2.4
        Operating System: Microsoft Windows

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Details:

interpn.m (& __interpn_lin__.cc) fail to operate properly in octave-3.2.4
(MingW build / Windows). It also fails in a self-compiled octave-3.2.4 under
MandrivaLinux.
It worked properly in octave-3.0.3 (VC build / Windows).
FWIW, the examples below work OK in ML.

Attached .mat file contains some test data that help to show the error.

octave-3.2.4.exe:2> load interpn.mat
octave-3.2.4.exe:3> whos
Variables in the current scope:

  Attr Name         Size                     Bytes  Class
  ==== ====         ====                     =====  =====
       Phi         26x9x51                   95472  double
       ans          1x11                        92  cell
       dd2          9x26x5                    9360  double
       dirlist      1x6                         18  cell
       ii           1x1                          8  double
       rm           1x9                         72  double
       t            1x5                         40  double
       tnum         1x51                       408  double
       zm          26x1                        208  double

Total is 13213 elements using 105678 bytes

octave-3.2.4.exe:4> dd2 = interpn (rm, zm, tnum, Phi, rm, zm, t)
error: interpn: incompatible size of argument number 6
error: called from:
error:  
C:\Programs\Octave\3.2.4_gcc-4.4.0\share\octave\3.2.4\m\general\interpn.m at
line 141, column 8
octave-3.2.4.exe:4>


In addition, interpn.m has a typo in line 5 of the first demo test: "AI="
should read "yi=".
But even after fixing this, interpn.m fails a number of demo tests:
---------------------------------------------
# DEMO 1
octave-3.2.4.exe:4> A=[13,-1,12;5,4,3;1,6,2];
octave-3.2.4.exe:5> x=[0,1,4]; y=[10,11,12];
octave-3.2.4.exe:6> xi=linspace(min(x),max(x),17);
octave-3.2.4.exe:7> yi=linspace(min(y),max(y),26)';      # Here yi was
replaced by "AI"
octave-3.2.4.exe:8> mesh(xi,yi,interpn(x,y,A.',xi,yi,"linear").');
error: interpn: incompatible size of argument number 5
error: called from:
error:  
C:\Programs\Octave\3.2.4_gcc-4.4.0\share\octave\3.2.4\m\general\interpn.m at
line 141, colu
mn 8
error: evaluating argument list element number 3
error: evaluating argument list element number 1
octave-3.2.4.exe:8>

----------------------------------------
# DEMO 2
<all initialization commands (lines 1..4) are identical to DEMO 1 so only the
call to interpn is shown:)
# .. init lines ....
octave-3.2.4.exe:9> mesh(xi,yi,interpn(x,y,A.',xi,yi,"nearest").');
error: operator -: nonconformant arguments (op1 is 17x1, op2 is 1x17)
error: called from:
error:  
C:\Programs\Octave\3.2.4_gcc-4.4.0\share\octave\3.2.4\m\general\interpn.m at
line 152, colu
mn 15
error: evaluating argument list element number 3
error: evaluating argument list element number 1
octave-3.2.4.exe:9>

-----------------------------------------
# DEMO 3
# .. init lines ....
octave-3.2.4.exe:9> mesh(xi,yi,interpn(x,y,A.',xi,yi,"cubic").')
error: cubic interpolation not yet implemented
error: called from:
error:  
C:\Programs\Octave\3.2.4_gcc-4.4.0\share\octave\3.2.4\m\general\interpn.m at
line 190, colu
mn 5
error: evaluating argument list element number 3
error: evaluating argument list element number 1
octave-3.2.4.exe:9>
# Note: This one performs as expected! as "cubic" is not implemented indeed

--------------------------------------------
# DEMO 4
# .. init lines ....
octave-3.2.4.exe:8> mesh(xi,yi,interpn(x,y,A.',xi,yi,"spline").');
works OK and gives a nice 3D plot.

# DEMO 5
# .. works OK and gives plot similar to demo 4 

For smaller-size test cases below the demo stanzas interpn.m seems to work OK
(I haven tested them all)..




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File Attachments:


-------------------------------------------------------
Date: Sat 12 Jun 2010 10:21:22 PM GMT  Name: interpn.zip  Size: 114kB   By:
philipnienhuis

<http://savannah.gnu.org/bugs/download.php?file_id=20740>

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